Single Stage vs. 2 Stage T-stat

[mrbee]

Hello, all. I am a newbie here, but I have been reading posts for a year or so. Excellent site, very helpful. I just installed a Bryant Evolution Plus furnace
(80%, 2 stage, VS fan), a Bryant single stage A/C condenser, and a W-R single stage touchscreen t-stat. I'm very happy with the install, good installer (Factory Certified, NATE, etc.). I read on here that a 2 stage furnace should always have a 2 stage t-stat. I spec'd a 2 stage t-stat for this job, but the installer vehemently insisted on a single stage t-stat. He said that the Evolution has its own board that controls the 2 stage logic/algorithms, etc. so there is no need for the t-stat to do that with a 2 stage t-stat, and that if I had a cheaper unit without the board, only then would I need a 2 stage t-stat the run the logic/algorithms, etc. He also mentioned that the condenser was only a single stage. Is the installer correct? If not, was he trying to keep the job within budget (is a 2 stage t-stat much more $ than a single stage t-stat?), or was he trying to avoid pulling new wires (the wire path in my house to the t-stat is a bit convoluted, perhaps the installer recognized this and was trying to avoid more labor cost on the budget? Does a 2 stage t-stat require more wires than what was on the 1960's vintage system that was replaced?) I'm trying to decide if I should go back to the installer now, while the system is very new, and request a swap-out to a 2 stage t-stat. The posts here say that you get better "comfort" with a 2 stage t-stat. My system seems very comfortable so far. "Comfort" is a bit vague. What specifically am I missing without a 2 stage t-stat? Your thoughts, input, and opinions would be most appreciated and thanks for reading!

[lra]

I am not familiar with that particular furnace. As a rule though, yes a 2 stage stat would be your better bet. The furnace is manufactured to provide multiple installation variables. It (the furnace board) doesn't know if you have a multiple zoned system, air flow characteristics of the stat location, etc. Unless the literature with the furnace specifically requires a single stage stat, I'd use one. And yes, there needs to be another wire for the 2 stages of heat.

[mrbee]

Hi, Ira, thanks for the response. Since the condenser is still only single stage, and if I usually run heating on "Auto" rather than on the "Fan On" setting, would a 2 stage t-stat really be cost-effective in terms of the cost to upgrade to the new t-stat, and the labor cost for pulling the new wire? Or am I really running a "tweener" system that is functioning more like a single stage system, so that a single stage t-stat isn't so bad? Thanks! mrbee

[indytech]

A 2 stage t-stat will help with heating will call for 2nd stage quicker than the control board on furnace. you need 2 stage heat 1 stage cool you will save money.

[beenthere]

The 2 stage stat will still provide better comfort then the boards logic.

As far as pulling more wires, he can use the Honeywell IAQ, it only needs 3 wires to the stat. It is more expensive, but saves teh labor of pulling new stat wires.


The furnace board will force second stage after the furnace runs for so long.
The stat will keep it in first stage as long as the temp is not dropping.
If it really didn't work better with a 2 stage stat, why would it have terminals for a 2 stage heat stat.

[mayguy]

I usually run heating on "Auto" rather than on the "Fan On" setting, would a 2 stage t-stat really be cost-effective in terms of the cost to upgrade to the new t-stat, and the labor cost for pulling the new wire?

Since you got a nice variable speed system, I'd suggest turning on the fan in the winter to move the air. It'll make the house more even in temps.

I'd go and put in the IAQ t-stat, they only need 3 wires, where most other two stage t-stat will need 5 or 6 wires.

[mrbee]

Hello, all, and thank you for all of the helpful and informative responses. You are all true professionals. I will study the IAQ unit and post how this issue turns out and resolves itself. A great weekend to all! mrbee

[Cmore]

This subject turns up in this group every few days. Why? Do the HVAC professionals have something against the manufacturers who design and build 2 stage furnaces. For me, as a consumer, if the manufacturer recommends a 2 stage thermostat, it should be installed. I had a Trane XV90 installed last month and frankly had to argue with the installer to have a 2 stage T installed. He thinks I'm crazy, spending extra monies for the 2 stage T. For 2 weeks before he installed the 2 stage T, the furnace ran on the timer and it ran often. Ten minutes on low then on high. Since installing the 2 stage thermostat, I find the furnace runs on low the majority of time and the temperature on the 'stat never varies. Simply put, would all you HVAC experts install what the manufacturers call for. I'm sure that most consumers who order a 2 stage furnace, would absorb the extra cost for the 2 stage stat.

[mrbee]

Cmore, I went around and around the horn with the installer on this issue while the install was in progress. It started to get a bit ugly and I backed off to the 1 stage t-stat. I couldn't figure out why there was an issue here, I thought maybe it was me being picky or something, it's been bothering me ever since the install, so I decided to post it up here. It looks like I have only 3 wires, previous posts indicated the IAQ only needs 3 wires. I have a W-R now, it's fine (except for 1 stage), does W-R make a 2 stage 3 wire t-stat like the IAQ? Again, thanks to all who responded.

[mrbee]

Hello all, again. I've been doing some homework (nothing else to do- home ill for 1 week!!). The current single stage t-stat is a W-R 90 Series #1F97-1271.
The 2 stage W-R t-stat I could switch to (it might be easier for the installer to swap me out to another W-R unit instead of a different brand i.e. Honeywell IAQ) is a W-R 90 Series #1F95-1277. Does this 2 stage W-R require more wire(s) to be pulled, or can it use the same amount of wires as the single stage W-R?? I tried to figure this out on the manufacturer's pdf wiring diagrams, but this is way beyond my expertise, the diagrams look like a foreign language to me and it's not just because I am ill! Your input and thoughts would be most appreciated once again, and many thanks

[beenthere]

It will need more wires then the IAQ.
Currently, teh IAQ is the only stat that only needs 3 wires to the wall stat and can still control 2 stage equipment.

[mayguy]

White Rodger is going to need 5 or 7 wires.

Power
Heat 1
Heat 2
Cool
Fan
Common (If not used, then battery must be used)
Dehumid (I am not sure if this t-stat has it or not)

IAQ

COM 1
COM 2
COM 3


3 wires goes down to an Equipment Interface Module, then it ties to the furnace.


http://yourhome.honeywell.com/NR/rdonlyres/5D84BA94-F3F7-464E-B290-ADB1AC64C197/1845/VisionPRO.jpg

[mrbee]

Thanks for the wiring info, this answers many questions I had!

[oloenneker]

has no one ever heard of a "add a wire" kit?

If you have four wires already to your stat, you can use the add a wire" kit to do the function of that fifth wire.

http://www.thermostatsusa.com/images/add.jpg

[beenthere]

Heard of it, never used one.

Wondering if the cost of the add a wire, and a good programable digital stat, isn't about the same as a IAQ stat.

[mrbee]

Good morning, all. While we are on the subject of wiring, add-a-wire, etc., I did some more homework. The Bryant Evolution furnace manual says that this unit has an Adaptive Mode where you can run a single stage t-stat with this 2stage furnace, by setting a DIP switch. I believe I am running in this mode right now with my single stage t-stat. The installer also mentioned this mode during installation. The Adaptive Mode sequences are start in low, switch to high, or start in high. Once in high, Adaptive Mode can't ever bump back down from high to low. The manual also states that with a 2 stage t-stat, the sequences are the same, except that the unit can bump back to low from high. How important is the bump-back capability in terms of gas savings and comfort? How often will the bump back to low sequence typically run? I'm still on the fence with going back to the installer for the IAQ. Knowing now that Adaptive Mode exists, should I just "live with" it as is, or should I still try to go for the IAQ? Again, many many thanks for all of your helpful advice. Regards, mrbee

[mayguy]

Heard of it, never used one.

Wondering if the cost of the add a wire, and a good programable digital stat, isn't about the same as a IAQ stat.

I am not a dealer so I have no clue, I am guessing they are going to come out close?



Good morning, all.

The Adaptive Mode sequences are start in low, switch to high, or start in high. Once in high, Adaptive Mode can't ever bump back down from high to low. The manual also states that with a 2 stage t-stat, the sequences are the same, except that the unit can bump back to low from high. How important is the bump-back capability in terms of gas savings and comfort? How often will the bump back to low sequence typically run? I'm still on the fence with going back to the installer for the IAQ. Knowing now that Adaptive Mode exists, should I just "live with" it as is, or should I still try to go for the IAQ? Again, many many thanks for all of your helpful advice. Regards, mrbee

I used to work with a dealer who did Carrier,(Bryant is owned by Carrier). You are right about the Adaptive Mode. I am trying to recall it, and don't hold me to it.. I am sure the other Carrier guys can jump in and correct me.

-The board will see how long it runs till it shuts down. So let's say the furnace ran 20 minutes, and the shuts down. On the next call of heat, the board will keep the furnace in low, and if it runs longer than 20 min, it will then fire off in high fire till it shuts down. I honestly don't recall when it "rests itself" to the shorter run time.. I think it if the furnace ran 10 min and shuts down, it reset itself.???

So you will never see it go back into low stage. It's for pure COMFORT, not savings. For an example, last Feb, we had a cold snap of -15 to -20 below zero, my furnace pretty much fan non-stop for few days, and it cycled in and out of 2nd stage as needed. Everyroom in the house was warm and comfortable! neighbor behind me got the same floor plans is ours, and they have a single stage, and one room was warmer, others was colder... cuz the furance was cycling on and off.

[BaldLoonie]

To me, the idea of 2 stage is long run periods on low in bitter weather. That can't happen with any timer. The longest Carrier allows is 16 minutes then it times to high and as you said, stays there until the stat satisfies.

Look at May's post about his 2 stage experience during a cold snap. I bet he was more comfy that way than a timer, adaptive or otherwise, that wouldn't allow long low cycles. Seems to me, shortly after timing to high, it could satisfy the stat. Shortly after the sequence would repeat. Many cycles instead of just purring along on low.

[beenthere]

With a 2 stage sat. If you set the temp back at night, you can have a quick recovery in the morning if you want. Or can have adaptive recovery turned on, and not use second stage it it isn't needed. Can't do that with the furnace board.

If you bought a 2 stage furnace to save money on the heating bill, you won't.

Its for comfort.

[mayguy]

With a 2 stage sat. If you set the temp back at night, you can have a quick recovery in the morning if you want...

Been made a good point there about morning recovery.. I set ours back to 62, and back up to 68, it fires off on 2nd stage right away, then throttle back to 1st stage to slowly warm up the home to comfort.

[Airmechanical]

you wont live any longer, but you will experience a higher comfort level with 2 stage control via 2 stage t-stat!



.

[tpa-fl]

This subject turns up in this group every few days. Why? Do the HVAC professionals have something against the manufacturers who design and build 2 stage furnaces. For me, as a consumer, if the manufacturer recommends a 2 stage thermostat, it should be installed.
<snip>
He thinks I'm crazy, spending extra monies for the 2 stage T. For 2 weeks before he installed the 2 stage T, the furnace ran on the timer and it ran often. Ten minutes on low then on high. Since installing the 2 stage thermostat, I find the furnace runs on low the majority of time and the temperature on the 'stat never varies.

Let's be honest. There's a lot of people who "do HVAC". There's very few who understand HVAC. Most of the professionals who post here are probably the ones who go the extra mile -- they're reading up and learning more about their trade after-hours, so these comments aren't aimed at them. Then there's the "old school" people who've been doing HVAC work forever and don't like change. They'd prefer to do things the same way they've done them for the past 30 years and don't see any reason to change.

I recently encountered an HVAC tech who's been doing HVAC work for more years than I've been alive. He couldn't understand why anyone would want a variable speed, multi-stage heat pump system in Florida. He also still installs mechanical thermostats and doesn't understand why anyone would want to use a set-back thermostat. Honeywell VisionPro or Honeywell IAQ with humidity control? Never. Not surprisingly, he didn't believe in Manual J, S, or D. "1 ton per 500 sqft is good enough" was his thoughts on sizing. I don't doubt that he does get a lot of business, as his prices are pretty low, but at the same time I question if he's able to truly provide home comfort for his customers.

[Cmore]

Let's be honest. There's a lot of people who "do HVAC". There's very few who understand HVAC. Most of the professionals who post here are probably the ones who go the extra mile -- they're reading up and learning more about their trade after-hours, so these comments aren't aimed at them. Then there's the "old school" people who've been doing HVAC work forever and don't like change. They'd prefer to do things the same way they've done them for the past 30 years and don't see any reason to change.



Tpa-Fl: Agreed. My experience in purchasing a new system, is that a lot of the installers and owners of HVAC just don't care. They seemed interested in the sale, but not the installation or service. On this site, the pro's talk about installation, surveys etc., but in practice how do you find a good HVAC tech?? I called five dealers, got two quotes over the phone, two came to the house and one never showed at all. Of the two that came to the house, only one provided a written quote. How's that for professionals? Really, I'm not bitter, but as a consumer making a fairly large purchase I expected more professionalism. However.........

[mrbee]

Hello, all. The plot thickens! I popped the Honeywell IAQ issue on my installer today. He was very nice about it, he's a good guy, he was very honest as always and said he wasn't familiar with the product and would have to study it. He made one significant "counter argument" to the IAQ, for discussion purposes. He said that most of his customers prefer to use the Adaptive Mode with a single stage t-stat, because those with 2 stage t-stats tend to experience a certain "lock up" condition unique to 2 stage t-stats. This is where, he says, the furnace bumps up to high, and then bumps back down to low (the Adaptive Mode is totally incapable of bumping back to low) and then it stays in low for extended periods of time, never cycling off. He says these customers don't like the furnace running for so long, and that this drives up gas consumption, too. I seem to remember a post here some time ago that also mentioned this argument. Is there any validity to this "lock up" argument? My experience so far in Adaptive Mode has been that after high shuts off and no low kicks in, and with the fan set to "Fan On", the register air became so cool before the furnace hit the next on cycle that I had to reset the fan to "Auto". My household members thought I had the A/C on and questioned why I shelled out for a new system! Again, thanks to all of you who have responded. I will keep you posted on where this goes. Regards, mrbee

[mayguy]

He said that most of his customers prefer to use the Adaptive Mode with a single stage t-stat, because those with 2 stage t-stats tend to experience a certain "lock up" condition unique to 2 stage t-stats. This is where, he says, the furnace bumps up to high, and then bumps back down to low (the Adaptive Mode is totally incapable of bumping back to low) and then it stays in low for extended periods of time, never cycling off. He says these customers don't like the furnace running for so long, and that this drives up gas consumption

"Lock Up".. Is he saying that furnace stays on 1st stage too long?

The ideal behind the two stage t-stat is longer run time for COMFORT, I don't think there will be that much increase of gas usage. With the burners running in low stage will use less gas, but over all i think it should be the same amount if the furnace was running on high fire for a shorter time.

I don't know where you are out of if you get the extream temps like we do here in Minnesota. But, I only saw my furnace run steady in low stage when the temps started to drop below -5 to -10 with out 2nd stage, then 2nd stage start to cycle on and off when it got about -20.

[mrbee]

mayguy, he's saying it stays in 1st/low stage for too long after high brings the temp up to the set point. I'm in Northern Ohio, gets pretty cold here. Thanks, mr bee

[mayguy]

If he's talking about recovery, yes, the t-stat will cycle back into 1st stage to get the things slowly warmed up in the home. I'd rather see that than get the object's temp warmer than the air temp higher.

[beenthere]

The "lock up" as he's calling it, is easy to prevent. Both first and second stage have their own CPH settings.
By adjusting these you can prevent that from happening.

[mrbee]

Hello again all. On Monday, my installer said he was not familiar with the Honeywell IAQ, and he would have to study it. He also said that he might come out to make some adjustments to Adaptive Mode, so that pehaps I wouldn't need IAQ at all. I haven't heard back from him. Is there anything different/unusual/complicated about an IAQ install that requires extensive "studying"? What "adjustments" to "Adaptive Mode" could he possibly make that would give the same comfort as a true 2 stage t-stat? I just want a true 2 stage stat, not some work-around because I have only 4 wires and the pull path is very convoluted up to the stat. As far as cost goes, the IAQ is more $ than the W-R, I would be willing to pay the difference if the installer would credit me with the W-R cost I already paid for and take the W-R back; is this fair? (btw, the contract called for "t-stat compatible with 2 stage furnace", I thought I paid for and was getting a true 2 stage stat until the job was underway and then I got stuck with the 1 stage stat, probably when the wires path issue was first discovered). As far as his labor cost to put in the IAQ, I'd be willing to split that with him, but I don't know if this task is like a 2 hour job or a 6 hour job for installation, programming, test mode, etc., my "educated guess" is it's closer to 2 hours. And if it is like 2 hours, why is it such a big deal for the installer to make this right? Don't "study" it, just set up the swap out appointment and do it, yes? Am I missing something? Your thoughts and input would be most appreciated, and a great Holiday to all! mrbee

[tpa-fl]

I don't see what the installer's objection to running in single stage is. Having lived with multi-stage air conditioning for 6+ years, I can't imagine going back to running an all-or-nothing system. Both my mutant Lennox/Copeland custom system (installed 2001) and my new Carrier Infinity system at my newest residence (installed 2 weeks ago) run most of the day, in low stage, providing a near perfect climate inside. The "adaptive mode" he's talking about is when the thermostat is the recovery mode, when it's trying to come back from a set-back, like when it's been off during the day and trying to heat/cool the home to the desired temperature by the time you get home. The Honeywell stats do cycle between high and low stage as needed when running normally. Having seen the mathematical algorithms of the IAQ, I can assure you that it does everything it can do operate in low stage as much as possible in recovery, but on those coldest/hottest days of the week, low stage won't be enough to cut it and it'll jump up to high to get the building up to the proper temperature, then switch back to low to maintain temperature. THIS is the way 2-stage equipment is SUPPOSED to run! I don't think you mentioned the exact model #'s on your furnace, but just a page from my 2-stage heat pump:

1st stage: 14,000 BTUs @ 1.07 kW = 13,084 BTU per kW
2nd stage: 23,050 BTUs @ 1.98 kW = 11,641 BTU per kW

So, it's actually more economical for me to run on the low stage as much as possible. Not that 2,000 BTUs is a huge difference, BUT still, if I'm paying for that killowatt, I'd like to get the most bang for my buck.

Just get someone who is willing to put in the IAQ. I've not run the IAQ at any of my homes, but I have run it's older sibling, the 2-stage VisionPro stat, for the past 3 or so years without incident. Even on absolute junk equipment, it was able to make a comfortable environment. Any good competent tech should be able to install an IAQ in a matter of minutes, probably 15-30 at most. MAYBE 1 hour at most if you've never installed any of the recent Honeywell thermostats. If anything, it's one of the simplest installs out there.

Unlike "normal" thermostats, the IAQ stat has 2 separate pieces, the "control" and the "equipment interface module." The control itself is what hangs on your wall. It does all of the measuring, thinking, etc. It then sends signals DIGITALLY to the equipment interface module. THIS IS DIFFERENT from just about every thermostat out there, but no big deal from an installer's aspect. The digital signalling is how the stat is able to use 3 wires instead of 10+ that it would normally take to control everything the IAQ is capable of. The equipment module gets mounted near the furnace and is wired to the furnace like an ordinary thermostat would.

The contract wording is very unclear. In theory, anything is compatible with 2-stage operation... but it doesn't specifically say "2-stage thermostat." From a legal perspective, "compatible" does not equal "2-stage", only that the thermostat would be able to turn the system on & off.

Personally...if you're paying for the stat, I don't think you should be required to pay for the labor, since this is something which should have been done properly the first time. If he was throwing in the difference between the IAQ and the WR stat, then I'd absolutely pay for labor. Not sure how extensive the work was at your place, but I always insist that there are extra wires pulled because you never known when a wire is going to break or get damaged. Likewise, most of the contractors I work with will do the same unless it's totally impossible to pull new wire without doing major damage to the existing structure. Even then, they'll try to find an alternative location for the new thermostat to avoid future problems.

[mrbee]

tpa-fl, you make a very astute observation regarding the contract language, it is very vague and ambiguous. I would have changed that language, but I didn't know about the 1 vs. 2 stage t-stat issue until the job was well underway, and then the decision was made mutually with the installer, in the "heat" of installation, to just go with a 1 stage. Afterwards, I researched the issue on here and realized that I had a problem. Since I am partially "at fault" here, that's why I am willing to pay towards the t-stat swap-out and the labor to do so. Plus, the IAQ upgrade cost is very small in comparison to the overall job cost. I told the installer that I was open to working out a parts/labor figure that's fair to both of us, so he has to know I'm willing to contribute. That's why I am puzzled that I haven't heard from him. I'm a businessman, if it were me with a slightly unhappy customer, I 'd sleep on it, make my playcall on how to handle the situation, call the customer the next day and tell the customer I can swap you out for $xxx and if that's OK my guys will be there next Tuesday at 9am. The installer offered to first trouble shoot the system, maybe he would play with the CPH, but the fact remains that the furnace board can't bump back to low from high while the IAQ can. Regards, mrbee

[lra]

Something maybe hasn't been mentioned. If the furnace board sends the call for high and the ambient temp is moderate, won't the furnace overshoot the stats intended temperature ? With the fan delay on break inherent in all modern furnaces, I would think the call for heat when high is not truely needed, would overshoot desired temp by several degrees.

[tpa-fl]

Something maybe hasn't been mentioned. If the furnace board sends the call for high and the ambient temp is moderate, won't the furnace overshoot the stats intended temperature ? With the fan delay on break inherent in all modern furnaces, I would think the call for heat when high is not truely needed, would overshoot desired temp by several degrees.

It won't overshoot, but will short-cycle. The original poster has a W-R stat... very basic logic (well, a simple algebraic formula) in them. Once you get above the set-point, it's going to cut power to the W terminal. It's just going to race to get to the very close finish line then have to slam on the brakes.

[lra]

My thought was, rather than cycle back to low to finish the heat call, it stays on high until satisfied... on a moderate day, the residual heat from the unnecessary "high" call will infuse the heat exchanger and duct work and then on a "w" break, the IFM time delay will put that heat in the conditioned space, probably more heat than the anticipator can compensate for. No ?:confused:

[tpa-fl]

My thought was, rather than cycle back to low to finish the heat call, it stays on high until satisfied... on a moderate day, the residual heat from the unnecessary "high" call will infuse the heat exchanger and duct work and then on a "w" break, the IFM time delay will put that heat in the conditioned space, probably more heat than the anticipator can compensate for. No ?:confused:

Indeed, there would be residual heat left in the heat exchanger... not sure on a gas furnace how much heat that would be. Obviously, it'd be more than if the hx only has low-fire heat on it. If the hx was large & heavy enough, that could be a decent amount of heat. We do know that the delayed-off on air cons is good for almost a whole 0.5 SEER, so heating wouldn't be all that different. Never played with a gas furnace, don't have 'em down here in gas-less Florida.

[mrbee]

tpa-fl and ira:

from the Bryant manual:

Two Stage Heating (Adaptive Mode) with Single stage Thermostat:
g. Switching from High to Low Heat- the furnace control CPU will not switch from high-heat to low-heat while the thermostat R-to-W circuit is closed when using a single stage thermostat


Two Stage Thermostat and Two stage Heating:
b. Switching from High to Low Heat- if the thermostat R-to-W2 circuit opens, and the R-to-W1 circuit remains closed, the furnace control CPU will switch the inducer motor IDM speed from high to low. The high heat pressure switch relay HPSR is energized to open the NC contact and de-energize the high heat gas valve solenoid GV-H1. When the inducer motor IDM reduces pressure sufficiently, the high heat pressure switch HPS will open. The gas valve solenoid GV-M will remain energized as long as the low heat pressure switch LPS remains closed. The blower motor BLMW will transition to low heat airflow five seconds after the R-to-W2 circuit opens.

Does this help your discussion posted above? Regards, mrbee

[beenthere]

It wouldn't over shoot like you think.
His current stat should should be able to preventhat from happening by its CPH setting.

The IAQ module can be intimidating when someone first looks at it.
Might be why he wants to study it.
Or he just doesn't want to do it.

[lra]

How will the cycles per hour prevent overshoot ? I was thinking coming home, stat is @ 60, he truns it to 70, it's 60 outside so no real load, the furnace goes to high fire, building residual btu's in the furnace and duct that will have to go somewhere.

[beenthere]

I wasn't thnking of just recovery.

It might over shoot by a degree, but I doubt it.

Since there is not much of a load, doubtfull it would go to second stage.

And it would be no different then a single stage furnace of the same size, coming out of recovery.

[tpa-fl]

The Honeywell IAQ (and many of their other high-end stats) use calculus algorithms to determine when it should turn on & off the equipment. It isn't a simple matter of "If it's below/above the setpoint, turn on/off." The Honeywell algorithms take into account a) how far from the setpoint is the current temperature, b) how long has the room been above/below the setpoint, c) the rate of rise/fall of temperature, d) cycles per hour as specified by the installer. Based on all of that, is how it determines what it needs to do. This is why there is often a delay on the Honeywell stats when you've adjusted them. They've reduced the delay on the newer ones with faster processors and also a "bypass" algorithm which will just start the equipment up based on the manual override and then figure out what needs to happen once the equipment's up and running.

Using all of this, it can "see" when it's getting close to the setpoint and will back off. If you've ever had one of the higher-end stats in your home/office and had a noisy enough AC to notice, you would indeed find that if you've told it to only run cooling for 3 cycles per hour, it'll probably cycle the system 2-3 times per hour if the demand isn't so high that it needs to stay on during the whole hour.

[mrbee]

Hello again, all. It's been a while. My Installer finally scheduled the job to swap out my single stage W-R t-stat for a Honeywell VisionPro IAQ t-stat. He had some personal issues which prevented him from dealing with this sooner. I'm fine with that. Installers need to be cut some slack just like anyone else, they are not robots. My Installer told me that this is the first time he is installing an IAQ. His crew is awesome, they did a fine job with the initial furnace/AC install, but I'm still a bit "nervous". So I decided to familiarize myself a bit with the Honeywell installation manual while I'm waiting for the install. I have 3 quick questions based on the manual, the Installer may not know the answers if this is his first IAQ install. They are:

1. I have a 2 stage furnace with a VS fan. Is the IAQ compatible with a VS fan?; the manual talks only about 2 stages, not VS fan at all

2. In a related vein, the "Fan Control-Heating" installer setting #0180 in the IAQ manual gives 3 applicable choices- equipment controls heating fan, or equipment controls Stage 1, thermostat controls Stage 2+, or auto discover/detect. What's the best choice, or what can I tell the Installer to help him make this choice?

3. The IAQ manual is ambiguous about where to mount the EIM (Equipment Interface Module), it just states "mount it on the equipment"!! I don't think it should be drilled into the side of the furnace or the coil box (LOL). If it's mounted on the plenum, there are hot/cold temperatures through the plenum that might bork the EIM circuit board, correct? That leaves the return air metal duct run that goes down to the filter box. The humidistat control is already mounted there, there's still room over the humidistat on the metal duct for the EIM to be mounted. Is this a good location? Any other suggestions? What do you guys usually do with this location issue?

Once again, I thank all of you in advance for your professional, courteous and intelligent responses and assistance. Regards, mrbee

[mayguy]

1. I have a 2 stage furnace with a VS fan. Is the IAQ compatible with a VS fan?; the manual talks only about 2 stages, not VS fan at all

Most two stage are variable speed.. The t-stat don't need to know what the fan is.



2. In a related vein, the "Fan Control-Heating" installer setting #0180 in the IAQ manual gives 3 applicable choices- equipment controls heating fan, or equipment controls Stage 1, thermostat controls Stage 2+, or auto discover/detect. What's the best choice, or what can I tell the Installer to help him make this choice?

#180 at 0 you want the equipment control control fan.



3. The IAQ manual is ambiguous about where to mount the EIM (Equipment Interface Module), it just states "mount it on the equipment"!! I don't think it should be drilled into the side of the furnace or the coil box (LOL). If it's mounted on the plenum, there are hot/cold temperatures through the plenum that might bork the EIM circuit board, correct? That leaves the return air metal duct run that goes down to the filter box.

I have mine mounted on the return duct.. You can have it mount on the wall near by if you want.



The humidistat control is already mounted there,

You can have them remove the humidistat, and use the EIM board to control it, and also use it for slowing the blower down in dehumid mode (cooling).

[mrbee]

Mayguy, thank you for the quick and informative response! I'm not so "nervous" now! Happy 4th (yes, it's soon) to you and all here. Regards, mrbee

[beenthere]

What mayguy said.

The first one is the hardest to install.

Your installer will learn to love the IAQ stat, once he becomes familair with it.

[mrbee]

Hello, all. Mayguy, "upon further review" (and after viewing a related post), I have a follow-up question on your last post regarding dehumidification on the Honeywell IAQ. I have an Aprilair Model 700 Automatic Humidifier with an "Automatic Mode" humidistat. This was put in with the initial install in May, I haven't even used it yet. For this reason, on my upcoming Honeywell IAQ swap-out, I would prefer not to have the Installer disconnect/remove the Aprilaire humidistat and use the IAQ to control dehumidification instead, as you suggest in your post. Do you have any suggestions, ideas etc. that I can pass along to the Installer in terms of keeping the humidistat but still using the IAQ to control dehumidification? I don't understand how this works or the interplay, if any, between a humidistat (used in winter with the furnace) and dehumidification (used in summer with the condenser). And what should I tell the Installer (reminder: this is his first IAQ install) in terms of dealing with the IAQ set up #0379 in the install manual (Dehumidification Control); the options are "no dehumidification control" or "dehumidify with air conditioning". The furnace has a VS fan, the condenser is single stage. Thanks so much! mrbee

[mayguy]

I would prefer not to have the Installer disconnect/remove the Aprilaire humidistat and use the IAQ to control dehumidification instead, as you suggest in your post.

You can keep the Aprilaire if you want, they are good controls.. What I like about the IAQ, I can tell it to "force fan on", only with fan or heat.. ect.. I have mine set to "Force fan on".. That way it can keep up with the humidity in the home, and not wait till the next cycle of heat.



using the IAQ to control dehumidification? I don't understand how this works or the interplay, if any, between a humidistat (used in winter with the furnace) and dehumidification (used in summer with the condenser). And what should I tell the Installer (reminder: this is his first IAQ install) in terms of dealing with the IAQ set up #0379 in the install manual (Dehumidification Control); the options are "no dehumidification control" or "dehumidify with air conditioning". The furnace has a VS fan, the condenser is single stage. Thanks so much! mrbee

There is two ports on the EIM, one is for the humidifier, and another for dehumid control on your furnace's board. Basically it's a mini relay, make sure he reads the install manual on how to wire this up to the furnace.

#379 set to 1.

What happens here if the home is above setpoint, say 45%, the blower on the furnace will stay running at a slower speed till the humidity is below set point, then it tells the board to bring the blower up to it's full speed.

The "Over-cool" will take place if the humidity in the home is 5% above set point.. say house becomes 51% humidity, the t-stat will turn on the a/c and tries to dry it out.. it may drop the house temp 1, 2, or 3˚ below set point.

This should only be used on coils that has TXV on it.

[dash]

It will need more wires then the IAQ.
Currently, teh IAQ is the only stat that only needs 3 wires to the wall stat and can still control 2 stage equipment.


Carrier's new Edge stat ,can do that and dehum with two wires from stat to indoor unit.

[tbox8098]

Why wiouldn't you use this for your stat. Wh yon earth are we talking about the IAQ. IT can't hold a candle to what the Evolution can do. I know that the ysay it can do a lot of functions and I agree withg that but Bryant/Carrier holds 20+ patents on the way the evolution communicates. I think we all did this homeowner a disservice by directing him to a standard 2 stage stat.

[beenthere]

Carrier's new Edge stat ,can do that and dehum with two wires from stat to indoor unit.

LOL.. Then I was still right, the IAQ is still the only stat that only needs 3 wires. :)


Thanks for the heads up.

[mrbee]

Mayguy, thanks for the quick and informative post. Now it all makes sense. IAQ install is scheduled for the week after next week, I will post results of install, comments, observations, etc. when install is finished. Again, a great Holiday week to you and all here. Regards, mrbee

[mayguy]

Glad we are able to help you understand how the IAQ works. Keep us posted on your results.

Tbox did make a good point, about the Evolution control.. Guess I didn't catch that up front. but the IAQ will work just as well. Hasn't the dealer even brought this control up?

[tbox8098]

The IAQ will not work as well as the evolution control. The evolution control was designedand tested specifically for the Bryant furnace, butthe Honeywell has been designed for a broad spectrum of manufacturers. Thus what I said about the evolutioon being able to offer more features than the IAQ

[AcDOCnTRAINING]

Any,Carrier/Bryant/Payne unit with a variable speed motor, along with any dehum control will dehum the air. All u need is to run a wire to the DEHUM on the fan control board and remove the J1 jumper. The Evo/Infi controls are the best, it has real time cfm & static pressure checks, VS motors for the blower & condenser. My unit here at home is runing at 20.6 seer rating my bill droped $93.66 the first month.

[mrbee]

The Installer has never mentioned the Bryant controls. Regards, mrbee

[tpa-fl]

MrBee: What's the model # on your furnace? An Evolution control might be the best option for your system. Having the Carrier Infinity control myself (same as the Bryant Evolution other than name sticker), I can say that it, when paired with an Infinity/Evolution air handler/furnace, offers more control and better management of airflow than any 3rd party control/thermostat can.

[mrbee]

Hi Tpa-Fl, the Model Number on the Bryant furnace is #315AAVO48090, Evolution Plus 80v Series. Regards, mrbee

[tbox8098]

Install the Evolution control, it is easier to wire than the IAQ and again it is designed specifically for the furnace.

[mrbee]

tbox, the Installer probably didn't mention Evolution because 1. I wanted a touch-screen (have kids here, touch is easier to use), and 2. I only have 4 wires to the stat and pulling new wires was too costly/impractical based on stat location (how many wires are needed for Evolution?) Regards, mrbee

[beenthere]

I think you'll find the Evolution control only nees 4 wires

[AcDOCnTRAINING]

[QUOTE=mrbee;1537056]Hi Tpa-Fl, the Model Number on the Bryant furnace is #315AAVO48090, Evolution Plus 80v Series. Regards, mrbee[/QUOT

Thats a nice furnace 90,000 BTU, 1500 cfm Variable speed blower w/Evo board. Don't think of it twice a get yourself the Evo control interface. Easy four wire set-up u will luv it!

WHEN INSTALLING A FLOAT SWITCH ON EVO/INFI SYSTEM DO NOT INTERUPT POWER ON ANY OF THE FOUR WIRES (A,,B,C,D)! DO IT ON FEED COMING FROM TRANSFORMER TO BOARD!

[tpa-fl]

tbox, the Installer probably didn't mention Evolution because 1. I wanted a touch-screen (have kids here, touch is easier to use), and 2. I only have 4 wires to the stat and pulling new wires was too costly/impractical based on stat location (how many wires are needed for Evolution?) Regards, mrbee

Screw the touch-screen. I had a Honeywell VisionPro 8321 stat on my old system, but decided to retire it when my Carrier Infinity system was installed. The difference in performance between the IAQ and the Evolution control on your system will be substantial. The Evolution control was made for that system, the IAQ is a 3rd party product which tries to do the best it can, but wasn't designed specifically for your unit. For example, the Infinity control switches between 14 different fan speed on cooling, based on indoor temperature & humidity conditions. It even handles how long the blower should run after shutting down the compressor based on humidity conditions. The IAQ will only be able to access 2-4 fan speeds at best and only has crude controls to determine how long the blower runs after the compressor shuts off (0 seconds or 90 seconds, no regard for humidity.)

I agree that the VisionPro looked better on the wall than the Infinity/Evolution control I have on there now, BUT, the performance is well-worth it. It's looks weren't real attractive to me initially, but the gentle white glow of the screen when it's on standby has grown on me.

And yes, it only uses 4 wires: 24v (hot), 24v (common), Data +, Data -.

[tbox8098]

the evolution needs only 4 wires and although it is not touch screen ut is easier to operate than the IAQ and it moniters the system operation for any troubles.

do yourself a favor and get the stat that is designed to operate your furnace

[mrbee]

Hello all, I will check out the Evolution t-stat, although my Installer already ordered the Honeywell IAQ last week and he has agreed to credit me with the cost of the W-R single stage t-stat that will be removed. Setting this swap-out up took some time, as the Installer is very busy right now. If I call him now about the Evolution (a 3rd t-stat in the mix), he might punch me out. Thanks again for all of your concern and professional input. Regards, mrbee

[tpa-fl]

Call him about the Evolution control anyway -- it'll greatly shorten his install time at your home. The Evolution stat literally "looks" to see what equipment is installed and automatically configures itself. It takes longer to screw the stat to the wall than it does to set it up.

[mrbee]

Tpa-fl........will do, appreciate the advice. Regards, mrbee

[mayguy]

MrBee, any update for us?

[mrbee]

Hello again mayguy and all! Yes, I have an update for you, and I am very FRUSTRATED! IAQ installation day was supposed to be a week ago Monday (I decided to go with the IAQ over the Evolution based on cost factors). Anyway, no one showed up at the designated install time, and I took off of work to be there. I called the Installer, they forgot to call me to tell me that the Supplier (a major, factory-authorized Honeywell distributor with like 15 locations) had ordered in error just the t-stat and not the module (EIM), and that the module was back-ordered! I was under the impression that the t-stat and the EIM were sold together as a kit, since you need both to run the system. I also thought that, assuming they could be ordered seperately (as perhaps a replacement part) that a major Honeywell distributor would KNOW how to order it as a combined kit, and that it HAS TO be ordered as such! The Installer told me he was up to his neck with the situation, and told me to call the distributor directly. I lit up the distributor a bit, and he managed to produce the EIM at my Installer's door this past Tuesday. However, the distributor would absolutely not address the Version 2 firmware issue, he ignored a FAX and 2 calls on this! I figured the payoff would be no Version 2 delivery when all was said and done. When the Installer called to reschedule the install, I begged the Secretary (who I've talked to before, this is my second install with these folks) to check for the "sideways 2" on the back of the t-stat (thanks to you guys on here, I knew how to identify the firmware!!!!). The Secretary acted like I was absolutely NUTS to ask about "firmware versions", but reluctantly agreed to open the box and check, after I told her that if it wasn't a 2 version, we are back to square one and would have to re-order from the Honeywell distributor. She told me there was a "2" on it, and I scheduled the Install for this Friday. Another update will follow. I'm absolutely puzzled that all of the folks in this chain of command know so little about the IAQ, which is very widely distributed, and is even sold on eBay! I'm keeping my fingers crossed at this point, and trying to keep my cool. Thanks for all of your help and concern, especially mayguy, and also thanks for providing in other posts the important firmware identification method. Regards, mrbee.

[mayguy]

Thanks for the update, sorry that you had a hassel on it.

I've gotten 3 IAQ, and they all were in one box.... I am sure they do make them apart like you said as replacements.

[beenthere]

You have to order a YTH9421 to get the stat and eim.

A TH9421 is just the stat.

[mrbee]

beenthere- I think that was part of the problem here. I saw the item listed at different web sites as either "YTH" or just "TH" with no explanation for the difference between them. I probably gave the Installer the "TH" number, as that's how the Honeywell site itself shows it. That's probably what was ordered. I don't expect the Installer to be aware of this subtle nuance, especially since this is his first IAQ install. But you would think that the Honeywell distributor would know the proper coding (and remember, this is the same distributor who also ignored my requests to address the Version 2 firmware issue). I felt like I was ordering space shuttle parts or something like that here! Will (hopefully) update over the weekend. Regards, mrbee

[beenthere]

I found that out the hard way myself. :)

[mrbee]

Hell again, all. Here's the UPDATE on yesterday's IAQ install. Everything went great! The IAQ is awesome! The dehum function is incredible, it's taken out much of the musty smell and dampness in the house. I like the continuously lit backlight, too. It seems like the IAQ logic has lengthened the cycles a bit so there is less swing between cycles, and the temp is much more even. A great BIG THANK YOU to all on here for helping me with this project! Regards, mrbee

[mrbee]

Ooops, I meant "hello" again all! It was "hell" for a while, but now all is well. I may have a few more observations in a day or too, but sometimes when I finish composing the message here, it asks me to log in again and then the message doesn't post and disappears. That's what happened to the first one, and in my haste to re-post because I then had a honey-do chore to do, I typo's the greeting!! Anyway, thanks again all. Regards, mrbee

[mayguy]

Glad to hear that you like it alot. I am a proud owner of it, and has done well for us last week when it was pretty humid outside.

I was at a few diffrent friends yesterday, and they got a standard system. man I sure can tell that their home isn't as dry and comfortable as mine!

[mrbee]

Hi mayguy and all, here are some more in-depth observations on the IAQ, now that I have some quiet time. None of this is earth shattering, but if I help 1 person like I was helped here, I will feel like I have returned the good deed.
1. The IAQ installation went smoothly. The only issue was that the A+ installer had some wiring confusion between dehum with the AC versus dehum with a whole house dehum unit (I am using the AC option). He eventually figured this out.
2. I have a half basement which is finished, the other half is a conditioned crawl space (it has two supply registers) with a concrete floor. It has always been damp and musty in that cave. The dampness infiltrated the finished part of the basement and often came upstairs either through the walls, the supply lines or both. Both the old and the new HVAC system had this issue. When the IAQ booted up, the humidity was 59% in the house (it's been very humid here lately, even though temps have only been 80-ish, Northern Ohio area). I set the dehum for 45% and it's been hummin', the system holds 45% easily, and the damp and musty smell is gone. What a pleasure. I can also run a degree or two higher on the temp setpoint as it feels cooler now with the humidity down.
3. When the dehum bumps the fan down, it's almost like having a 2 stage condenser, even though it's only a 1 stage. The bump down has smoothed out and evened out the cooling. It used the blast real cold, and then get stuffy between cycles. Now it is much more even. The IAQ logic seems to sense things better and runs the condenser a bit longer than the W-R t-stat did, I always felt like the W-R bumped the condenser off too quickly even at the identical CPH setting.
4. There was a ton of plenum sweat above the coil box. There were some open joints where new sheet metal was installed and not sealed well, the Installer aluminum taped those for me after the IAQ project, I appreciated this. The tape plus the IAQ dehum has reduced the sweat by 90%.
5. Lastly, I never mentioned this so as to not complicate issues, but I have a "true" 2 zone system, 2 furnaces in the basement, each with their own supplies/returns. One feeds the basement and 1st floor, the other feeds the 2nd floor. Both condensers are outside. So I actually installed 2 IAQ's (double the fun, LOL!!). Anyway, the IAQ somehow seems to better sense that there are 2 zones, and as a result, there is more even cooling on both zones now. It just feels more even and comfortable. Seriously. I don't think I am imagining this.
Well, that's it. I'll just read for a while unless something new pops up. I'm sure this system will be nice and cozy on the heating side when the old Lake Erie snow squalls begin. Have a great summer all. Thanks again! Regards, mrbee

[snoopygis]

mrbee:

I'm glad to here everything went well with your IAQ installation. I haven't been around for awhile now, but I'm checking out posts because I need to purchase a new furnace. I'm looking at the Carrier Infinity, high eff., 2-stage VS. Now, I'm in the same boat you were in; I have a 1 stage t-stat and will want to get a 2 stage instead and I may have to get the IAQ to accomplish this. I plan to get the humidifier at the same time (we use a lot of heat here in the winter and the house gets dry, I live north of Toronto). I have some questions that based on your recent experience, you may be able to answer (or anyone else for that matter).

You mention that you had a damp basement and I have the same issue. In your last post you said "I set the dehum for 45% and it's been hummin', the system holds 45% easily, and the damp and musty smell is gone."

1) How does the dehum function work on the IAQ system?
2) Is the Evolution t-stat the same as the Carrier Infinity Control?
3) You mention you have a true 2-zone system. Is it possible to have a 2-zone system with only 1 furnace? I have the same problem that I'm sure other people have in that when the AC is on, the basement is too cold, the main floor is comfortable and the upstairs is too warm and in the winter the basement is cold, the main floor is comfortable and the upstairs is not warm enough.
4) Is there any way to fix #3?

Thanks for letting me post these questions. I wanted to send you a PM, but the admin has disabled that function, anyone else have this problem?

[mayguy]

mrbee:
1) How does the dehum function work on the IAQ system?
If it's wiered up right, the IAQ will slow down the blower and with a slower blower, the air has time to go over the coil to dehumidify the air. And say if you have ti set at 45%, and the home humidity goes over 5% of set point, the t-stat will turn on the A/C to dry out the home, that will "Over cool" up to 3˚ below set point.


2) Is the Evolution t-stat the same as the Carrier Infinity Control?
Same thing.. Just a diffrent name stuck on the cover.


4) Is there any way to fix #3?
Making sure the ductwork are sized right, dampers in the duct work to balance out the air flow, returns in the right area.. As cold basement in winter, any return in the basement near the floor? Heating system cycle on and off often, or long run time?

[dash]

Basement ,first and second floors.Two or three zone zoning system ,each with it's own temp. control is the way to go .

Existing duct system may be difficult or near impossible to modify for zoning.Ideally eachfloor would already have it's own "trunk duct" that zoning dampers for each zone could be installed in.

[snoopygis]

If it's wiered up right, the IAQ will slow down the blower and with a slower blower, the air has time to go over the coil to dehumidify the air. And say if you have ti set at 45%, and the home humidity goes over 5% of set point, the t-stat will turn on the A/C to dry out the home, that will "Over cool" up to 3˚ below set point.


Thanks.




Same thing.. Just a diffrent name stuck on the cover.


That's what I thought




Making sure the ductwork are sized right, dampers in the duct work to balance out the air flow, returns in the right area.. As cold basement in winter, any return in the basement near the floor? Heating system cycle on and off often, or long run time?

My house was built in 1986, so I have no idea if the ductwork is sized correctly or if there are dampers in the ductwork. No return in the basement near the floor (I'll check tonight for sure). Heating system DOES cycle on and off often.

[snoopygis]

Basement ,first and second floors.Two or three zone zoning system ,each with it's own temp. control is the way to go .


Do you mean that If I want a 2 zone system, I'd have to have two t-stats?



Ideally each floor would already have it's own "trunk duct" that zoning dampers for each zone could be installed in.

I have no idea if each floor has it's own "trunk duct". How can you find out if each floor has one? Thanks.

[dash]

Zoning by "equipment" you could a system and stat for each floor.

Zoning by "a zoning system" you would have one system,plus a zone damper to regulate air flow ,and one stat per zone.

If the basement is unfinished you may be able to tell a lot about the duct system by just looking at how it runs there,in relation to where your supply grilles are on each floor.If the ducts are all enclosed,it would be difficult to tell .

[mrbee]

Snoopy- the IAQ and the Evolution t-stat are both excellent, I went with the IAQ's because: 1. I like a touch screen and 2. the IAQ's were more expensive than the W-R's I swapped out, but less expensive than the Evolution, it was a price compromise, and remember that I have 2 systems so the cost doubles with each item. I think in retrospect (hindsight is always 20/20) that the Evolution furnace board is a bit complex and "fussy", and that perhaps an Evolution would have made more sense if dollars were not an issue. I say this because my Installer (who is very sharp/experienced) had a real tough time wiring the Evolution furnace board to the IAQ dehum function. I'm still studying/reviewing this, but the IAQ dehum user menu shows an "Auto/Off" option on my IAQ t-stats. The Honeywell manual says this option only appears when using a whole house dehum system (which I'm not using, I doing dehum off the AC, which is the second IAQ option where it trims off the fan speed). If you are not using a whole house dehum system, the IAQ manual shows the screen as blank where "Auto/Off would appear. This is either a Honeywell manual glitch (doubtful but possible), or somehow the Evolution board's logic and the way I was wired is making the Evolution board think it's running a whole house dehum system even though it really isn't. It may be that the Evolution's board's built in logic somehow overrides the IAQ. In any event, the dehum is working fine on my IAQ's so maybe it's a moot point, just a bit strange and made me curious. As mayguy (who helped me with the IAQ's) correctly pointed out, the IAQ can trim the blower speed to cut humidity, and it can also bump the AC on if the humidity goes over the humidity setpoint on the IAQ. It seems like I get more instances of the latter (especially late at night/early morning when heat is not up as much as humidity is) but I can't always tell when the blower speed is cut back as they are very quiet to begin with, and it only cuts it back 40%, so it's hard to tell a difference, to me at least. Plus, most of the time the AC cycle cuts the humidity on its own and doesn't need a blower trim off at the end of the cycle. Bottom line: IAQ dehum works great, house no longer smells damp, cooling is more even, and I have raised my temp setpoints 2 degrees due to lower humidity (although I have always run the upstairs zone setpoint about 3degrees above the downstairs zone, but that's a whole other discussion). Regards, mrbee

[mrbee]

Hello all again. I know I said that I'd ride off quietly into the sunset following the successful Honeywell IAQ install, but I just figured out how to upload photos. So attached are photos of the old Bryant equipment, circa 1968, the new Bryant equipment, and the recently added Honeywell IAQ interface module. Regards, mrbee

[mayguy]

Very clean job that they did.. Looks like you found a good dealer there.

I take it they didn't tie the humidifier onto the IAQ?

[mrbee]

Hi, mayguy, thanks for the approval on the job, good to hear this. You made a sharp observation (as always) that the humidifiers are not tied to the IAQ. This was the Insaller's first IAQ (he's a "believer" now) and I didn't want to complicate things more with a humidifier tie in (he had a tough time with the dehum function wiring (see earlier post). Also, the humidifiers have some kind of outdoor sensor and run automatically at where you set them on the Aprilaire control, so I figured that would be enough. In retrospect, I probably should have done the tie in, but I figured I could do it later if I really wanted it, now that everything is hooked up and there are extra non-used wires from the EIM to do so with. Thanks again for your help/input. Regards, mrbee

[dash]

Does the IAQ read the static,if not did they test it?

[mayguy]

Does the IAQ read the static,?

No, it does not read the static.

[mrbee]

dash- I know for sure that a load calc was done, I don't know if SP was tested or not, but I think it was, because there was a lot of duct measuring and counting/viewing of supply runs, registers, and returns. The plenums still sweat a bit, especially when the condenser runs frequently (the sweat is confined to the new metal connector box just above the coil box in the photo above). It's not the filters. I had the metal connector box joints taped and caulked to eliminate air leakage as a possible cause. The dehum in the basement zone is set at 45% and is holding there. Would an SP issue be related to the sweat issue? Or, what was your reasoning for asking if SP was tested? Regards, mrbee.

[dash]

If the static was extremely high it could reduce the air flow,and cause sweating,not saying it is.

Looked like they may have added pleated filters,is why I asked.Adding more restrictive filters often requires some duct remediation,like larger return drops,grilles ,etc.,varies with each job.

Plus I was curious about the IAQ control and how it compares to the Carrier/Bryant contols.

[beenthere]

Plus I was curious about the IAQ control and how it compares to the Carrier/Bryant contols.

It can't at this time read the static of the system.
Its air filter change indicator is based on time.
It can slow the blower down, and cool to dehumidify.
It can control a humidifier, has option to humidify only during heat calls, or bring on fan when RH drops.
Can control erv's/hrv's, fresh air damper.
Its Duel fuel capable.
4 stages heat, 2 cool.
Can display OD temp, RH.
Can use multiple remote sensors.
Has fan recirc ability.
Selectable non program, 5-2, or 7 day.
2 or 4 event program

May not do everything the Infinity control can, but for ver 2.3 ECM systems, its the next best thing. IMO

[mrbee]

dash- you are correct that there are pleated filters on the new system, and I know that there was no duct remediation. The old system on the same duct system used to have blower motor howl unless I used a very thin type of fiberglass filter made by Purolator. To try to reduce the possibly high SP-caused sweating on the new system, what type of filter can/should I try to experiment with to see if this helps, what's in there now is labeled as a "Filter Cartridge", any suggestions/thoughts? Thanks! mrbee

[nina]

mayguy wrote:
> set at 45%, and the home humidity goes over 5% of set point, the t-stat will turn on the A/C to dry out the home, that will "Over cool" up to 3˚ below set point.


just got my hands on a new 2-stage control which has an even tighter control program in that once humidity% setpoint +2% is reached it runs 1st stage at ultra-low speeds and stops running at -2%, with 0˚ change in temperature

will install it tomorrow

[mayguy]

mayguy wrote:
> set at 45%, and the home humidity goes over 5% of set point, the t-stat will turn on the A/C to dry out the home, that will "Over cool" up to 3˚ below set point.


just got my hands on a new 2-stage control which has an even tighter control program in that once humidity% setpoint +2% is reached it runs 1st stage at ultra-low speeds and stops running at -2%, with 0˚ change in temperature

will install it tomorrow

Ultra low? You mean 1st stage? If I or Mrbee had two stage, the system would run in 1st stage, and slow the blower down to dehumidify the house. I don't think I have seen mine overcool down to 3˚...

[nina]

mayguy wrote:
>Ultra low? You mean 1st stage?

as I wrote, it runs 1st stage at ultra low speed, airflow is reduced to 50% below normal 1st stage variable blower speeds. this has the added benefit of causing no change to temperature while maintaining the tightest control of desired humidity.

[mayguy]

mayguy wrote:
>Ultra low? You mean 1st stage?

as I wrote, it runs 1st stage at ultra low speed, airflow is reduced to 50% below normal 1st stage variable blower speeds. this has the added benefit of causing no change to temperature while maintaining the tightest control of desired humidity.

How is the blower slowed down 50%?

Link us to the t-stat, and what brand of furnace do you have?