XL20i - Fluster Cluck

[JNo]

I inquired with a reputable local contractor about adding a zone for my upstairs. They instead suggested a zoned system saying it would provide comfort for the whole house. The cost was not quite double, but I was willing to pay it for the comfort.

Around Memorial day I had a 2-zone Trane xl 20i/xv95 system installed and since then we've had a hard time getting the humidity down. It tends to stay above 60% RH.

These guys have been responsive, but not necessarily helpful, and as we come upon shoulder season, I don't have a lot of confidence in this system and I need some guidance on how to proceed in a way that's fair to them and me.

The system as installed:
XL 20i 5-ton unit
XV95 95000 btu furnace
(2) TH8321 Honeywell stats
HZ432 zone controller.
All new return ducts and new supply ducts upstairs (downstairs ducts are in the concrete slab)

The proposal:
XL 20i 5-ton unit
XV95 95000 btu furnace
(1) XL900 Trane stats
(1) Honeywell remote stat
HZ432 zone controller.

As you can see they didn't install the XL900 stat. I was told I would get a fully communicating system that would be capable of getting the humidity down to 45%. Needless to say I didn't and it doesn't. And I've discovered some mold in my house as a bonus.

Here are some of the things they have tried to address the humidity in the house.

They checked and changed the stat/zone controller wiring - 3 to 4 times.
I asked them to set the dip switches for the Comfort-R ramp - it hadn't been set so they did.
They added two relays to control which stages are fired.
They added a jumper from R to O on the control board on the furnace.
They removed one relay - leaving one in place.
They finally increased superheat from 8 to 12 degrees,
lowered the air flow from 400 to 350 CFM/ton,
and removed the remaining relay.

Last night they said they modified the HZ432 control which may achieve what they were trying to do with the relays, and we did get down to 53% RH, but it was back up to 60% by bedtime and was ~60% this morning.

When the system runs continuously it seems to be able to remove moisture from the air. But when it doesn't run a lot, the RH goes up.

Since it was installed the indoor humidity has been in the high 60's per the Honeywell stat although it seems increasing the subcooling and reducing the airflow helped quite a bit. Now the upstairs RH is close to 50% but downstairs struggles and rarely breaks 60%.

What concerns me is that it seemed like the airflow and subcooling were finally starting to help until it cooled off a bit - the temperatures only got to the low 90's. At these lower temps and reduced run-time, the downstairs RH went back to the mid to upper 60's.

So here I am in August looking at the shoulder season in a month or so and I have no confidence whatsoever that I'll be able to keep my home below 60% RH when things cool a bit, much less next spring when it gets sticky. I'm already at 350 CFM/ton in the heat of the summer and I can't imagine it gets any easier to dehumidify than it is now.

My question:
1. How much more am I paying to cool at 350 cfm/ton vs. 400 cfm/ton?
Like most of you reading this I've suspected this system is oversized and they're using the reduced airflow to compensate for this.

2. Same with the increased subcooling. It sounds like this increases pressure and therefore work the compressor needs to do, increasing wear and energy costs. With the Trane Charge-Assist, I would assume they unit was properly charged to start with. Is 8 degrees standard, or did they miss this too? Or is it a "fix" to compensate for an oversized unit?

3. How do I salvage this - these guys are 2(+) months into this and haven't been paid - which makes me very uncomfortable. I don't see anything close to what I was promised in terms of comfort and can't imagine paying what this system costs when I receive only part of its functionality and comfort.

But at the same time, its not like these guys can take their system back and put my old system back in.

I want to be fair to these guys, but at some point you've got to cut bait.

What do you guys think?

JNo

[BaldLoonie]

How was 5 tons determined?

What are the relays for? The 432 should be set to determine staging based on % of zones calling. I don't think the XV95 can use the communicating stat, only the XC95. If 350 CFM/ton doesn't do it, nothing the communicating control could do anyway.

Don't run the blower constantly, be sure both stats are on auto for lowest humidity. How cool are you keeping the house? How tight is the house?

[beenthere]

They should have used thermostats that can slow the blower. The TH8321 can only over cool to dehumidify.

What size was your old system.

Did they do a load calc, or just guess what size new system to put in.
may be oversized.

Just curious, what size sq ft is your house.

[dan sw fl]

Around Memorial day I had a 2-zone Trane xl 20i/xv95 system installed and since then we've had a hard time getting the humidity down. It tends to stay above 60% RH.

These guys have been responsive, but not necessarily helpful, and as we come upon shoulder season, I don't have a lot of confidence in this system and I need some guidance on how to proceed in a way that's fair to them and me.

All new return ducts and new supply ducts upstairs (downstairs ducts are in
Here are some of the things they have tried to address the humidity in the house.

They checked and changed the stat/zone controller wiring - 3 to 4 times.
I asked them to set the dip switches for the Comfort-R ramp - it hadn't been set so they did.

When the system runs continuously it seems to be able to remove moisture from the air. But when it doesn't run a lot, the RH goes up.

Since it was installed the indoor humidity has been in the high 60's per the Honeywell stat although it seems increasing the subcooling and reducing the airflow helped quite a bit. Now the upstairs RH is close to 50% but downstairs struggles and rarely breaks 60%.


What concerns me is that it seemed like the airflow and subcooling were finally starting to help until it cooled off a bit - the temperatures only got to the low 90's. At these lower temps and reduced run-time, the downstairs RH went back to the mid to upper 60's.

I'm already at 350 CFM/ton in the heat of the summer and I can't imagine it gets any easier to dehumidify than it is now.

My question:
1. How much more am I paying to cool at 350 cfm/ton vs. 400 cfm/ton?
Like most of you reading this I've suspected this system is oversized and they're using the reduced airflow to compensate for this.

3. How do I salvage this - these guys are 2(+) months into this and haven't been paid - which makes me very uncomfortable. I don't see anything close to what I was promised in terms of comfort

and can't imagine paying what this system costs when I receive only part of its functionality and comfort.

But at the same time, its not like these guys can take their system back and put my old system back in.

JNo

What's your indoor temperature?

[JNo]

Thanks BaldLoonie, BeenThere, and Dan for the quick responses.

I never saw a Manual J worksheet, but they did a survey of the house, noted the construction and insulation, inspected all the rooms, looked at all the supply and return vents, and we talked about which rooms had comfort issues. I believe, but can't say for certain that a computer program was mentioned. If they didn't do one they certainly had all the information for one.

The house is a 2400 sq. ft 1-1/2 story. Downstairs is 1600 sq.ft. and up is 800 sq. ft. Both floors are full 8' height. We are planning to add on a room upstairs so I had them size it with approximately 300 extra sq ft. - but the upstairs is not the problem.

The size of the old unit may not help much. We bought this house from an older couple who occupied either the upstairs or downstairs but not both at the same time. As such they had a single 3-ton unit that would be diverted via a manual damper to either the upstairs or downstairs ducts. We ran this system last summer -constantly adjusting the damper - and it never kept up.

Relays - The relays were to keep the compressor from going to 2nd stage with only one zone calling. I believe they were mis-wired too and ended up calling both zones with any cooling call.

We set the stats at 78, but with the humidity suppression, the stats call for cooling 3 degrees below that.

The house was built in 1974. I haven't had a blower door put on it, but most of the houses in this neighborhood are regarded as well-built. I have asked each HVAC contractor that I've had out, and I've been told the house is not as tight as the homes built today, but its still pretty tight for a house built back then.

Thanks,
JNo

[2old2rock]

5 tons seems high. Ask the installing company to show you how they came up with that number.

[Mike8189]

I got the same unit in South Florida and have no confidence as of yet. I have no humidity problem just usage of power. I have my thermostat set at 76 it is 81 out side. My unit will kick between 1st and second stage on average of every 10 min with a minute in between stages. This killing the power consumption on my house..I have mt second visit tomorrow to fight this issue.

[dash]

Could have bought the brand that has a manufacturers, Satisfaction or your Money Back!

Did you consider that?


It makes everyone more careful, and you have some recourse!


Have you called Trane yet?

[Mike8189]

what brand is that?

[dash]

what brand is that?

Carrier, check their website for CFAD Dealers.

[hidalgo1301]

Does this t-stat come with precision dehumidification? I am only familiar with lennox (comfort sense 7000) What is the opinion of re-heat dehumidification (humiditrol)? I have only installed one on residential, worked very well.

[Daltex]

Is it cycling on/off even in 90+ OD temps? Just wondering if it's capable of locking out the 2nd stage. Leave all zones open. See if it holds the 78* setpoint. Just a thought as it may show if it is sized wrong??? Just thinking out loud I guess.

Is this an attic install or do the returns run though the attic? May be a gross leak that is drawing in humid attic air.

I'd be po'd if they didn't offer the XC furnace if it's true that that's the one that communicates.

Many newer systems are made to reduce sensible heat at the cost of the latent heat. Oversized coils enable the manufacturer to produce the high SEER #'s that sell these premium systems. It may be that a better evap. coil selection may provide better latent heat removal.

Post the evap coil model # and we'll see where it is on the latent to sensible range.

One final thought is the condensate line. If it's on the negative pressure side of the blower, post a pic of the p trap. I still think it's staging up to 2nd stage when not necessary but just trying to add some things to think about.

[JNo]

Is it cycling on/off even in 90+ OD temps? Just wondering if it's capable of locking out the 2nd stage. Leave all zones open. See if it holds the 78* setpoint. Just a thought as it may show if it is sized wrong??? Just thinking out loud I guess.

It does cycle off and on and it seems to be running first stage unless both zones are calling.

I'll try continuous running with both zones open this weekend with the single stage test function on the honeywell controller and let you know what I get.



Is this an attic install or do the returns run though the attic? May be a gross leak that is drawing in humid attic air.

The returns come through the attic to my garage installed unit. I don't think its a leak issue because the upstairs humidity is quite a bit lower - low to mid 50's. Since I have common returns, a leak should affect both zones.


I'd be po'd if they didn't offer the XC furnace if it's true that that's the one that communicates.

Many newer systems are made to reduce sensible heat at the cost of the latent heat. Oversized coils enable the manufacturer to produce the high SEER #'s that sell these premium systems. It may be that a better evap. coil selection may provide better latent heat removal.

Post the evap coil model # and we'll see where it is on the latent to sensible range.

4txcd010cc3hcaa


One final thought is the condensate line. If it's on the negative pressure side of the blower, post a pic of the p trap. I still think it's staging up to 2nd stage when not necessary but just trying to add some things to think about.

Its on the positive side - below the coil on a downdraft unit.

Thanks for looking into this.

JNo

[mark beiser]

They didn't install the XL900 thermostat because there isn't any way it could work with the zone control.
Unfortunately Trane doesn't have a zone system out for the Comfortlink II communicating equipment yet.
Until such time as they do, I won't be putting any zoned systems using the Trane communicating equipment.

Sounds like you have a mess there, and a contractor possibly in over their head. :(

[Airmechanical]

They didn't install the XL900 thermostat because there isn't any way it could work with the zone control.
Unfortunately Trane doesn't have a zone system out for the Comfortlink II communicating equipment yet.
Until such time as they do, I won't be putting any zoned systems using the Trane communicating equipment.

Sounds like you have a mess there, and a contractor possibly in over their head. :(

more specifically;

you can't properly zone a communicating system with the "communicating control"

the communicating system's can be set-up as a zone system using the analog 24volt control option

in general, a properly set-up zone system is not as easy as some may think



.

[BaldLoonie]

Still trying to figure out the relays when the 432 will stage based on % of zones calling.

Big unit, keeping house warm so the unit doesn't run a lot, would be harder to keep humidity down.

Mark, does the XV95 work with the 900?

[mark beiser]

Mark, does the XV95 work with the 900?

No, the XV95 is not the communicating furnace, the communicating version is the XC95. The XV95 is a 2 stage furnace, and the XC95 is a 3 stage.

I'm confused about the relays too, lol.

[JNo]

To add some clarity - the relays came out when they changing parameters in the Honeywell control - my best guess is they were trying to replicate the %-zone stage control.

And I looked in the installers manual - the XV does not have a wiring diagram for the XL900 - only the standard 24V inputs.

Speaking of which - one of the changes they made was to jumper from R to 0. I didn't see that in the manual. What does that do?

JNo

[wraujr]

"And I looked in the installers manual - the XV does not have a wiring diagram for the XL900 - only the standard 24V inputs"

That is because the XC95 is the communicating model for use with XL900.

Summary:
xL20i / XC95 / XL900 - Fully communicating, but NOT zoning capable.

xL20i / XV95 / plus zoning equip/tstats - NOT communicating, but zoning capable.

[crmont]

Where are the return air ducts? Is there a door dividing the upstairs? Check to see if the main area of the downstairs is being depressurized when only one zone is calling.

Jumping R to O-- If it was done on a heat pump then the heat pump would be locked into the cooling mode forever. If it were done on an A/C only unit, then they were trying to keep the zone panel or the air handler operating in the cooling logic only. (No heating stages or heating fan speeds)

[JNo]

Where are the return air ducts? Is there a door dividing the upstairs? Check to see if the main area of the downstairs is being depressurized when only one zone is calling.

all return air ducts are in the attic. And their is an open stairway between zones.

JNo

[crmont]

It's still worth checking. BTW Check my previous post on the O to R jumper.

[crmont]

Have they made sure that the outdoor unit is actually staging?

[wraujr]

"all return air ducts are in the attic. And their is an open stairway between zones."

Are you saying there is no first floor return???

Also did you say unit was on 1st floor or in garage??

[crmont]

No downstairs return? I am in a dry climate so I could get away with that but in Alabama I bet it could make a difference if it had a downstairs return. Returns on both levels is a good idea if possible for heating and cooling comfort and efficiency

Leaky ducts or air leaks around the Furnace (if the furnace or ducts are outside of the living space) will still depressurize the whole house and the downstairs is historically more leaky because of the exterior doors and such.

[JNo]

Jumping R to O-- If it was done on a heat pump then the heat pump would be locked into the cooling mode forever. If it were done on an A/C only unit, then they were trying to keep the zone panel or the air handler operating in the cooling logic only. (No heating stages or heating fan speeds)

Any idea why this would be done? What happens when heating season comes?

Also:
The returns for the downstairs are ceiling mounts that feed ducts in the attic

The indoor unit is in the garage

The outdoor unit appears to be staging: I can see the stage calls on the Honeywell controller and can hear a difference in fan speed and compressor noise.

JNo

[wraujr]

Are the return ducts for the 2nd flloor much shorter or longer than the 1st floor returns.

What I'm wondering is that zoning controls supply but where you pull from is controlled by size/length of returns. In other words, due to duct differences, could you be pulling mostly from downstairs, when most of call is zoned to upstairs, or vice versa.

Is it possible that if your zoning call is for upstairs and you're supplying upstairs, but due to return duct sizing most return air is coming from 1st floor. This could results in a depressurization of the 1st floor and more infiltration of outside humid air, hence raising 1st floor humidity. Since 2nd flloor usually has higher heat load due to attic, one might consider that majority of time is spent cooling upstairs zone.... Just something to ponder.

Also, if you're not getting good return from upstairs the supply will be reduced resulting in longer run times....

Could you give a rundown on each RETURN duct (location, size, and approximate length)??

[crmont]

Any idea why this would be done? What happens when heating season comes?

Also:
The returns for the downstairs are ceiling mounts that feed ducts in the attic

The indoor unit is in the garage

The outdoor unit appears to be staging: I can see the stage calls on the Honeywell controller and can hear a difference in fan speed and compressor noise.

JNo

I'm not sure why the jumper. Possibly a troubleshooting deal. Where exactly is r&o jumpered? What other wires are under the jumpered lugs?

Post a pic of the zone panel with the cover off.

The two stage HP's are in whole sizes so the next smaller HP is a 4 ton and is just over 3 tons on low stage. I wan't ignore the gorrilla in the room but it might be nice to see the load calc. Also you posted that you like 78 deg I think? It's a little high of a cooling setting for long enough cooling cycles to dehumidify. Also the cycles per hour could be adjusted to allow for longer run times. Many ECM blower systems have dehumidification jumper settings. This allows a dehumidification fan speed for a few minutes at the beginning of each cooling cycle.

Also that zone panel could be changed so 2nd stage is on a "timer" as opposed to ""percent of zones" calling. Changing that will force low stage to run longer. I suggest 30 to 40 min timer. It's in the zone panel setup. I would rather a pro did the change. Hope this helps. I'd personally like to see the man get paid so I hope all this is necessary:)

[Daltex]

=The two stage HP's are in whole sizes so the next smaller HP is a 4 ton and is just over 3 tons on low stage. I wan't ignore the gorrilla in the room but it might be nice to see the load calc.

Also that zone panel could be changed so 2nd stage is on a "timer" as opposed to ""percent of zones" calling. Changing that will force low stage to run longer. I suggest 30 to 40 min timer. It's in the zone panel setup. I would rather a pro did the change. Hope this helps. I'd personally like to see the man get paid so I hope all this is necessary:)

Wow, I didn't know that the first stage was over 75 percent of second. I was assuming closer to 60. That could be the problem if the load calc. wasn't done or not done right.

I haven't had a chance to look up the evap. coil yet but hope it's a sensible heat monster that could be swapped for something with greater latent removal.

The older, lower seer units really did a better job with the humidity. Marketing and the government makes the manufacturers go for the big seer numbers without regard to latent heat load.

Regarding the ducting, try a smoke test to see what the upper zone is doing to the down stairs pressure. Run the upper zone on 2nd stage without the downstairs running and crack an outside door. Hold a match along the cracked door opening and see if the flame,smoke if being pulled into the house or out. If neutral than no pressure change from ducting. Don't do this while windy outside or the results may be off.

I'm still upset that you spent a ton of cash on a system that doesn't communicate while zoning.

[beenthere]

On that 20i, first stage should be closer to 60%. Unlike unloading scroll systems.

[JNo]

I'm not sure why the jumper. Possibly a troubleshooting deal. Where exactly is r&o jumpered? What other wires are under the jumpered lugs?

Post a pic of the zone panel with the cover off.

The two stage HP's are in whole sizes so the next smaller HP is a 4 ton and is just over 3 tons on low stage. I wan't ignore the gorrilla in the room but it might be nice to see the load calc. Also you posted that you like 78 deg I think? It's a little high of a cooling setting for long enough cooling cycles to dehumidify. Also the cycles per hour could be adjusted to allow for longer run times. Many ECM blower systems have dehumidification jumper settings. This allows a dehumidification fan speed for a few minutes at the beginning of each cooling cycle.

Also that zone panel could be changed so 2nd stage is on a "timer" as opposed to ""percent of zones" calling. Changing that will force low stage to run longer. I suggest 30 to 40 min timer. It's in the zone panel setup. I would rather a pro did the change. Hope this helps. I'd personally like to see the man get paid so I hope all this is necessary:)

Per the attached, R and O are jumpered on the board on the furnace - the Red wire going from the far-right contact to the R contact near the center of the contacts)
Also this is a conventional system, not a heat pump, and I was told the first stage is 50%. I did have them set the Comfort R jumper that lowers the airspeed at the beginning of each cycle.

I took a look at the HZ432 and it's still or was set back to T_STAT zone control. I may talk to them about changing that to timer.

[beenthere]

Problem with using the timer for controlling second stage.
Is when both zones call, and you need second stage shortly after start up. You have to wait.

If you use number of zones, you don't need to wait, if second stage is needed.

Ask your contractor to install a humidistat to control blower speed.

[JNo]

Are the return ducts for the 2nd flloor much shorter or longer than the 1st floor returns.

What I'm wondering is that zoning controls supply but where you pull from is controlled by size/length of returns. In other words, due to duct differences, could you be pulling mostly from downstairs, when most of call is zoned to upstairs, or vice versa.

Is it possible that if your zoning call is for upstairs and you're supplying upstairs, but due to return duct sizing most return air is coming from 1st floor. This could results in a depressurization of the 1st floor and more infiltration of outside humid air, hence raising 1st floor humidity. Since 2nd flloor usually has higher heat load due to attic, one might consider that majority of time is spent cooling upstairs zone.... Just something to ponder.

Also, if you're not getting good return from upstairs the supply will be reduced resulting in longer run times....

Could you give a rundown on each RETURN duct (location, size, and approximate length)??

I've got 2 returns down and 1 up. All 18"x30".

The one upstairs return is approximately 25' of 12" duct with 2 90's.

Both downstairs returns feed into a 4-6' passage through the joists (2x10 on 16" centers) under the second story until it emerges in the attic space above the first floor. At this point the air travels through a fabricated sheet metal plenum(?) that feeds a 12" 90* boot. At this point it meet the attic duct work.

The far downstairs duct is 25' of straight 12" duct until it meets a Y where the near downstairs return air joins the flow. From here it is 14" duct for ~40-45" with 2 90's.

All duct is rigid. The duct sizes are from memory - I can check those tonight.

Thanks,
JNo

[BaldLoonie]

I'd leave % of zones calling. 1 zone, 1st stage. To force long run periods, leave the downstairs or set high. Cool air falls, run the sucker on low with upstairs doing the work as much as possible until the downstairs gets too hot.

[DanW13]

Ho could go with 2 seprate systems 1 for upstairs and 1 for the down stairs where the majority of living space is. Not sure if this is a feasible idea or not but it's Jjust a thought.

[hidalgo1301]

So I am to understand that you have a five ton system running off of one 12 and one 14(where the two 12s meet)? I hope you are looking at the duct wrong, otherwise you have a serious shortage..

[Illusion]

Relays for zone control staging with a Honeywell HZ432? I wonder if the installers read the manual for that zone controller. It does sound like they are in over their heads. I cannot see any reason why you would need relays for what you are trying to achieve with that setup.

[crmont]

Problem with using the timer for controlling second stage.
Is when both zones call, and you need second stage shortly after start up. You have to wait.

Exactly my point. The wait would give it a chance to dehumidify. It's already using % of zones so why not?

[crmont]

So I am to understand that you have a five ton system running off of one 12 and one 14(where the two 12s meet)? I hope you are looking at the duct wrong, otherwise you have a serious shortage..

Sounds like only 2-12" ducts at one point...

[crmont]

Per the attached, R and O are jumpered on the board on the furnace - the Red wire going from the far-right contact to the R contact near the center of the contacts)
Also this is a conventional system, not a heat pump, and I was told the first stage is 50%. I did have them set the Comfort R jumper that lowers the airspeed at the beginning of each cycle.

I took a look at the HZ432 and it's still or was set back to T_STAT zone control. I may talk to them about changing that to timer.

The jumper assures that the blower is only using the cooling speed schedule.

Yes forgot it was a trane, it's approx 60% on low.

[crmont]

Nutshell; As a trial, disable 2nd stage for cooling. See if the humidity issue is solved while summer is here. I honestly think that a 78 deg setpoint for cooling is going to be an issue on milder days. I bet it doesn't use high much anyway.

Have an airflow test done with the flow plate method. Check both stages.

Did they install the discharge air sensor for the zone panel in the supply duct? Did they set a low temp cutoff?

[beenthere]

Exactly my point. The wait would give it a chance to dehumidify. It's already using % of zones so why not?
He is only having a humidity problem in one zone.

Why lose temp control in the zone with no humidity problem, because he has to wait for the timer.

[crmont]

He is only having a humidity problem in one zone.

Why lose temp control in the zone with no humidity problem, because he has to wait for the timer.

So the downstairs has a chance to dehumidify.

[beenthere]

Using percent of zones will give the downstairs a chance to dehumidify.
Plus maintain temp.

[crmont]

Not if the upstairs calls. It's already using % of zones.

[beenthere]

That just allows all the zones to get too warm.

If they hooked up, and wired up his system right, he wouldn't have this problem.

The timmer works great, when your using single stage stats. But its a lack of comfort feature, not a comfort improvement feature.

[wraujr]

Using Manual D at 700 fpm (max) gives:
550 CFM per 12" flex

With 3 12" returns, 3 x 550 cfm = 1650 cfm which looks Ok for 4 tons and great for original 3 ton unit.

At 5 tons x 400 cfm/ton (typical) = 2000 cfm.
At 5 tons x 350 (current setting = 1750 cfm which is above worst-case calc.

Could he have too little returns??? Has ESP been checked???

Remember he was upsized from 3 to 5 ton.

Maybe - With 2x return downstairs he could be depressurizing 1st floor resulting in more humid air infiltration... Just a thought..

[crmont]

That just allows all the zones to get too warm.

If they hooked up, and wired up his system right, he wouldn't have this problem.

The timmer works great, when your using single stage stats. But its a lack of comfort feature, not a comfort improvement feature.

You probably know this already but % of zones is specifically for single stage stats, and you bring up a good point; If the stats are wired two stage then it's possible that the second stage is engaging when only the downstairs calls or if a manual adjustment by the HO is made frequently.

As far as the timer function;

We will have to agree to disagree unless we get some feedback from HO. I agree that % of zones should be the correct method but considering that it's (supposedly) already configured that way and he's having issues, I thought ether disabling 2nd stage or changing to a second stage timer configuration might shed some light on the humidification vs. capacity issue. Otherwise, do we concede that it's over sized and nothing can be done?

[beenthere]

It sounds like its an oversize problem.
As far as nothing can be done. Thats a possibility.

%zones, is for single stage stat systems. But can help in those applications that the customer, would spring for the duct alterations to have proper sized ducts.

[crmont]

It sounds like its an oversize problem.
As far as nothing can be done. Thats a possibility.

%zones, is for single stage stat systems. But can help in those applications that the customer, would spring for the duct alterations to have proper sized ducts.

Agreedcheers1

[JNo]

Thanks to everyone for the help on this.

Because of your help, the installer and Trane distributor are re-negotiating the price and are offering to replace my XV-95 with a XC-95 that does communicate with zones when Trane releases the model next Spring.

I'm not sure if I understood that this was just the XC furnace so equipped, or an XC furnace with a fully-communicating controller.

I'm also not sure if this passes the smell test though.

Has anyone heard of this new XC-95-type furnace or a fully-communicating zone controller from Trane (or Honeywell) due out next Spring? Or is somebody blowing smoke?

JNo

[crmont]

Thanks to everyone for the help on this.

Because of your help, the installer and Trane distributor are re-negotiating the price and are offering to replace my XV-95 with a XC-95 that does communicate with zones when Trane releases the model next Spring.

I'm not sure if I understood that this was just the XC furnace so equipped, or an XC furnace with a fully-communicating controller.

I'm also not sure if this passes the smell test though.

Has anyone heard of this new XC-95-type furnace or a fully-communicating zone controller from Trane (or Honeywell) due out next Spring? Or is somebody blowing smoke?

JNo


http://www.achrnews.com/NEWS/Home/Files/PDFs/Trane%20XC95%20Brochure.pdf


Just remember; to achieve dehumidification beyond normal with typical Hvac equipment, the indoor fan speed is simply lowered for a specific duration during a cooling cycle. If the cooling cycle is shortened because of over sized equipment, high thermostat set point and/or mild outdoor conditions then the cooling cycle may not be long enough to dehumidify to your expectations. This is why I suggested disabling second stage or lengthen the 1st stage cycle as a trial to see if your existing system has the ability dehumidify to your liking.

[JNo]

http://www.achrnews.com/NEWS/Home/Files/PDFs/Trane%20XC95%20Brochure.pdf

Just remember; to achieve dehumidification beyond normal with typical Hvac equipment, the indoor fan speed is simply lowered for a specific duration during a cooling cycle. If the cooling cycle is shortened because of over sized equipment, high thermostat set point and/or mild outdoor conditions then the cooling cycle may not be long enough to dehumidify to your expectations. This is why I suggested disabling second stage or lengthen the 1st stage cycle as a trial to see if your existing system has the ability dehumidify to your liking.

My bad for not fully updating you guys on what has happened since I lasted posted. They've been able to get the humidity to 50-52% RH fairly consistently except in the mornings when its closer to 60% RH.

I have noticed that with both zones calling, the system is staying in first stage with the Honeywell controller is set for T-STAT control of 2nd stage.

So although we are getting there in today's weather (High=80, Low=64, Full Sun), I'm certain I've left a lot on the table especially during the marginal cooling seasons in fall and spring. As a result, the installer and distributor agreed to replace the XV95 system with a fully communicating zoned system after Trane releases the new equipment next spring.

I've told them I will pay the balance of our renegotiated amount when I get a letter from the distributor confirming the trade of units next Spring.

My question was whether anyone had heard of this new Trane model scheduled for spring release or is this just a lot of hot air.

JNo

[Illusion]

Are you still having issues? Or did you get this resolved.

I am loving the humidity removal from my XL20i paired with my Honeywell HZ432. If you are still having issues I may have some thoughts that may help.

[Mr Bill]

08-13-2009, after 9 to 10 months I would say he's probably good to go by now, but you never know.

[Illusion]

Or maybe his spirit and will were finally broken.

[Mr Bill]

Or maybe his spirit and will were finally broken.


Hey after some of the "shoulda,wooda,coulda," feedback you get here, I could see that happening. Nothing like spending thousands on a new system, to have someone here tell you that you should have bought there brand. If some would focus more on helping the Home Owners here with there current issues, rather than shoving there brand down someone throat after the fact, probably a lot more would get accomplished in these posts. We only have been Preaching here for years that brand means nothing, it's the installation that's the key.

[hvac-master]

Has anyone heard of this new XC-95-type furnace or a fully-communicating zone controller from Trane (or Honeywell) due out next Spring? Or is somebody blowing smoke?

JNo

Fact: Trane will be providing a ComfortLink Zoning system in the near future that is capable of zoning communicating equipment with the TCONT900 comfort control.

There are many ways to provide better latent (moisture/humidity) removal on Trane Furnaces that utilize the variable speed blower which are well known by the factory and field service representatives.

[JNo]

Are you still having issues? Or did you get this resolved.

I am loving the humidity removal from my XL20i paired with my Honeywell HZ432. If you are still having issues I may have some thoughts that may help.

Thanks for asking. Predictably, it worked pretty well in the summer heat but this May has been moist - 60-70%RH downstairs, close to 50-55% upstairs.

JNo

[DavidNJ]

http://www.achrnews.com/NEWS/Home/Files/PDFs/Trane%20XC95%20Brochure.pdf


Just remember; to achieve dehumidification beyond normal with typical Hvac equipment, the indoor fan speed is simply lowered for a specific duration during a cooling cycle. If the cooling cycle is shortened because of over sized equipment, high thermostat set point and/or mild outdoor conditions then the cooling cycle may not be long enough to dehumidify to your expectations. This is why I suggested disabling second stage or lengthen the 1st stage cycle as a trial to see if your existing system has the ability dehumidify to your liking.

With a two stage or better modulating (Mitsubishi, Nordyne) compressor, shouldn't any unit be able to have reasonable cooling cycles for dehumidification?

[venting]

With a two stage or better modulating (Mitsubishi, Nordyne) compressor, shouldn't any unit be able to have reasonable cooling cycles for dehumidification?

Is there a way to extend 1st stage cooling on a 900 stat?

[JNo]

Fact: Trane will be providing a ComfortLink Zoning system in the near future that is capable of zoning communicating equipment with the TCONT900 comfort control.

There are many ways to provide better latent (moisture/humidity) removal on Trane Furnaces that utilize the variable speed blower which are well known by the factory and field service representatives.

HVAC-Master,

Have you seen a target date from Trane?

So far these guys have incrementally gotten me to a better place but no where near the system they sold me. Right now I've got 65% RH because of the ambient humidity and the relatively low temperatures.

In what direction should I steer them?

J No

[beenthere]

Is there a way to extend 1st stage cooling on a 900 stat?

Lower first stage CPH. And increase second stage CPH.

[JNo]

Lower first stage CPH. And increase second stage CPH.

Hi Beenthere,

I've got TH8321 Honeywell stats, is that possible with these?

JNo

[beenthere]

Hi Beenthere,

I've got TH8321 Honeywell stats, is that possible with these?

JNo

Yes it is.

The instructions how to are in the install manual.

[venting]

Thanks for asking. Predictably, it worked pretty well in the summer heat but this May has been moist - 60-70%RH downstairs, close to 50-55% upstairs.

JNo

At what set point are you getting 60-70%RH.

[venting]

Lower first stage CPH. And increase second stage CPH.

Thanks

[JNo]

At what set point are you getting 60-70%RH.

It's set for 77F but running to 74F with the humidity override.

[Illusion]

JNo,

I think you have all the pieces necessary to get where you want to go, just set up wrong. Maybe 5T is over capacity, maybe it won't be when you add 300 more square feet, maybe it will. But it is okay because the Trane XL20i is 50% capacity on first stage, not 60% or 70% as others have eluded to here. 5 ton may not have been the best choice, but it is where we are now. So lets figure out the most cost efficient and time efficient solution to your issue.

Our first goal is to increase stage 1 run time. Ways of doing this in order from best to worst solution: (In all cases you need to get rid of additional relays that are mucking with staging calls. With proper configuration they are completely unnecessary and counter productive to our goals.)

Tell the Zone controller to use the T-Stats for staging, then set the T-stat to some high settings before it calls for second stage. This is how my system is set up and I have my t-stat in zone 1 set up so that it will not call for 2nd stage unless the temp is out by 3˚ or more. I have zone 2 set up so that it will not call for 2nd stage unless the temp is out by 5˚ or more (it is a small zone) and I have zone 3 set so that it can never call for 2nd stage (it is a really small zone) All these adjustments are done at the t-stat of course because the zone controller has been removed from the staging decision process in this option. So in my case, I only kick into second stage when I am coming out of a setback, like when I get home from work.
If your t-stats are single stage only, or you cannot get the level of control to allow big temperature differentials with your specific stats you will have to allow the HZ432 to decide staging instead. Neither %zones nor Timer are ideal in your situation. I would go with Timer and set the highest value possible. (60 min in the case of the HZ432) If this turns out to be an unpleasant decision in the peak of summer it is an extraordinarily easy thing to adjust. Just pressing a couple of buttons in a menu on the HZ432.
Use %zones. This is where it gets interesting. I think this is where your installers incorrectly used relays to lock out second stage. If they set up the HZ432 as a 2 zone system, then it was always going to ask for second stage cooling per its internal programming. Percentage of zones calling energizes second-stage cooling when 50 percent or more zones are calling. This feature energizes second-stage heat when more than 25 percent of zones are calling. Third-stage of heat is energized when more than 50 percent of zones are calling. That is an unchangeable fact. The trick here is to set the HZ432 up as a 3 Zone system. You just tell the zoning board that it is 3 zones and hook nothing up to the 3 zone. Then if one zone were on that is 33% and if two zones were on that is 66%. That kills the need for additional relays and still allows the %zone concept to work.


Our second goal is to increase latent heat removal during run times. We have many ways to do that with the pieces of equipment that you have: (Listed in order of benefit)

Reduce CFM/Ton. You have already done this. 350 is a good setting, especially if you employ additional steps from this list. You can go lower but I would not if you do more of these steps as most of them further reduce CFM as well, just in different ways.
Set pre-run of Comfort R to max. I do not know if you have this level of control with the dip switch version of the air handler, but it is an option in the newer microprocessor controlled version. See also: http://hvac-talk.com/vbb/showpost.php?p=6506862&postcount=10
Set Fan ShrtRun to the maximum possible value.
Set Fan Off Delay to [none] or [1m50%] max. We do not want any of that moist air coming off the coil and back into your house. Certainly not when you are having other issues with humidity.
Make sure 'Purge Fan' in the HZ432 panel is set to [HVAC] which is the default. We do not want the panel asking for fan during purge as we have a humidity problem. We do not want any of that moist air coming off the coil and back into your house.
Make sure the t-stats do not have any fan off delay programed in. We do not want any of that moist air coming off the coil and back into your house.
Make sure that all t-stats are set to fan auto, not on. We do not want any of that moist air coming off the coil and back into your house.
Keep that jumper from R to O in the unit. It is what will allow the next step to work.
Make sure BK is not jumpered to R in the unit anymore as that is the way is comes from the factory. It looks like the installers already removed the jumper from your picture. (also a bad lazy half ass fix if I do say so myself) Now we need to connect the BK terminal from the unit to the BK terminal on the HZ432 controller. Now when only 1 zone is calling the HZ432 will de-energized the BK terminal and the air handler will run at 80% CFM when only one zone is calling. Do not reduce CFM below 350 if you do this step. See also: http://hvac-talk.com/vbb/showpost.php?p=6506932&postcount=31
Add a de-humidifiy switch to the system that energizes O G and Y1 but not BK. This would be a manual de-humidify option. This is getting to the extreme of solutions, but I have this and love it in the shoulder months. 79˚ in my house with 40%RH. This only works if you have normally open dampers. Do not reduce CFM below 350 if you do this step. See also: http://hvac-talk.com/vbb/showpost.php?p=6506932&postcount=31


Our third goal is properly charge the unit. No monkeying around with the charge on this unit. Should be charged to spec and not messed with.

You expressed concern about the additional cost to cool your home with the reduced CFM. Do not worry about it. It is minor and not the point anyway. The goal of having an HVAC system is not to cool your home, it is to make the interior comfortable. That includes humidity. If we need to adjust airflow in your climate to remove more moisture than the settings used for AHRI efficiency test, then so be it. As has been mentioned on this forum numerous times, the test are biased toward temperature reduction, so the manufacturers bias their equipment to temperature reduction vs moisture removal.

In fact, if we get your environment more comfortable at a higher temperature because we can effectively de-humidify the air, we may actually save energy and money in the end.

[beenthere]

JNo,
I think you have all the pieces necessary to get where you want to go, just set up wrong. Maybe 5T is over capacity, maybe it won't be when you add 300 more square feet, maybe it will. But it is okay because the Trane XL20i is 50% capacity on first stage, not 60% or 70% as others have eluded to here.

.

You got a Trane service facts PDF to post that says that?

While the first stage compressor may only be 50% capacity.

With those over sized coils. Its first stage capacity is a lot more then just 50%.

[Illusion]

I have the performance specs for my 2T XL20i. First stage is actually a little less than 50% total capacity. I cannot post the PDF. That would be a violation of trust from my source. I do not think Trane wants people looking at this stuff.

[beenthere]

Then post the data.

[Illusion]

I can post the Product Data PDF for that unit that clearly states: "• 50% or 100% capacity modulation" as a feature. Here it is...

As far as posting the data then, man, we are talking about 5 pages of tables with numbers. Here is one set for comparison.

High Stage:

95˚ OD AMB
63˚ ID WB
TOT CAP 22.3
1.73 KW
@800CFM
4TWZ0024A1 Paired with 4TEE3C03A1


Low Stage:

95˚ OD AMB
63˚ ID WB
TOT CAP 10.6
.82 KW
@400CFM
4TWZ0024A1 Paired with 4TEE3C03A1

[beenthere]

5 pages isn't much.

[Illusion]

Is that a joke? I am not going to type out 5 pages of charts.

[beenthere]

You just need to ask the OP his model numbers.
And post all of his units data.

[JNo]

Illusions,

Thank you for the thoughtful response. Here’s my feedback on your thoughts point by point.

Increasing Run Time:

1. The ‘432 is set to T-STAT for staging. In the house though, the stats are set as single stage stats. They only switch a single zone (1st) for both heat and cold. (I couldn’t make this stuff up.) These are Trane’s TCONT803 and not the Honeywell units originally installed. I do notice there are a few commands documented in the Honeywell 8321 (from memory) manual that are not available on the TCONT803 menu.

2. I’m going to leave these at single stage and leave the HZ432 at T-STAT until it gets warmer and then only if I need it.

3. I’m not to try the 3-stage/%-Zones solution until it gets warmer.

Increasing Latent Heat Removal:

1. I’m seriously considering going lower depending on what I can get with the more below.

2. I do not have the additional Comfort-R controls available on the newer models

3. Purge Fan is still set to HVAC

4. The Fan Off Delay is zero

5. Fan state on both stats is AUTO

6. R is jumpered to O

7. I don’t see a wire from BK to R. Are you telling me to cut the BK jumper wire on the board? Clarify so I can have them cut the jumper wire (?) and add the wire from BK to BK.

8. Externally switch O, G, and Y1 w/o BK. I may have them wire this. To be clear, does this get me 2nd stage heat removal at single stage air flow or 80% of 2nd stage airflow? If you could clarify this too, I would be willing to try it after #7 above.

Let me know about items 7 and 8. I’d like to get them to try these.

Thanks,
JNo

[mark beiser]

You got a Trane service facts PDF to post that says that?

While the first stage compressor may only be 50% capacity.

With those over sized coils. Its first stage capacity is a lot more then just 50%.

I'd need the exact coil model number to show you the ratings, but per the performance data for a couple of 5 ton XL20i system with 100k VS furnace I picked off the list at random, the 1st and 2nd stage total and sensible capacity are pretty near a 50%/100% split.

I printed off a couple of pdf files of the extended performance data for high and low speed of a 5 ton XL20i matched with a 95k XV95 and a slab coil. Results with an A coil are pretty similar, just slightly lower capacity.
Tables are generated with Trane's "Electronic performance data" utility on Comfortsite.

[JJDH]

20I 1st stage is 50%. that is why they have y lo on their ifc boards.....

[beenthere]

20I 1st stage is 50%. that is why they have y lo on their ifc boards.....


Pretty much all manufacturers have Y lo on their ifc boards.

[chuckcrj]

Ylo on trane Am Std gives you 50% of cooling cfm. other manufacturers are around 80%.

[beenthere]

Ylo on trane Am Std gives you 50% of cooling cfm. other manufacturers are around 80%.

Thats why you don't use Y lo with the 16i.

On other brands. If you use a dehumidistat, then Y lo is 50% or less(depending on brand).

[Illusion]

Illusions,

Thank you for the thoughtful response. Here’s my feedback on your thoughts point by point.

Increasing Run Time:

1. The ‘432 is set to T-STAT for staging. In the house though, the stats are set as single stage stats. They only switch a single zone (1st) for both heat and cold. (I couldn’t make this stuff up.) These are Trane’s TCONT803 and not the Honeywell units originally installed. I do notice there are a few commands documented in the Honeywell 8321 (from memory) manual that are not available on the TCONT803 menu.

So you are limiting yourself to 1st stage cooling as it is? That is not good news. I was hoping that we just needed to increase 1st stage run time. Maybe your system is way oversized.



2. I’m going to leave these at single stage and leave the HZ432 at T-STAT until it gets warmer and then only if I need it.

Cool. [pun] That is an easy thing to change in the HZ432 when it gets warmer.



3. I’m not to try the 3-stage/%-Zones solution until it gets warmer.

Good idea. No point in ever allowing 2nd stage if you are already limiting yourself to 1st stage and still not happy.



1. I’m seriously considering going lower depending on what I can get with the more below.

Okay. I spoke with an advanced technician about this. According to him, you could actually run the compressor on an XL20i with the indoor fan off. The XL20i has high and low pressure sensors and will protect itself. This a question probably better addressed by the other members of this forum. This is not an area of my expertise.



2. I do not have the additional Comfort-R controls available on the newer models

Sorry to hear that. At least make darn sure that Comfort-R is enabled then.



3. Purge Fan is still set to HVAC

4. The Fan Off Delay is zero

5. Fan state on both stats is AUTO

6. R is jumpered to O


That is all good. Sorry none of that was wrong. It would be an easy improvement.



7. I don’t see a wire from BK to R. Are you telling me to cut the BK jumper wire on the board? Clarify so I can have them cut the jumper wire (?) and add the wire from BK to BK.

As the unit ships from the factory there is usually a jumper from terminal BK to R at the terminal strip. Kinda like your jumper from R to O but shorter. I suspect your unit included one, but if it is not there the troubleshooters probably removed it to try to increase de-humidification. That is Trane's non communicating de-humidify terminal. If the unit has an O input, this is why we need the R to O jumpered, and BK is not energized the fan will run at 80% call. Options for using this terminal included a simple humidistat in the air stream in the unit, an additional wire from a humidity aware t-stat (only a good option if you are not zoning), and in our case a connection to a BK capable zone controller.

Unfortunately, if you lack this jumper, which you would easily see as a little wire or piece of metal between BK and R, then you will not get additional de-humidification by employing my suggestion. What you would get would be additional sensible heat removal when the second zone were calling. See, if the jumper is not there because they already removed it, then this whole time your system has been running at 80% of 350CFM/Ton.

I suppose if you went lower than 350/ton then it will be really important to hook up that BK to your zone controller so that you can get some real cooling in the summer with multiple zones calling. As it is now, if I am right and that jumper is missing, then you have the same thing as setting your airflow to 280CFM/Ton. Well not really. Same in a cooling call. The 80% reduction does not take effect when there is a heat call, so 350/ton in heat and 280/ton in cooling.


8. Externally switch O, G, and Y1 w/o BK. I may have them wire this. To be clear, does this get me 2nd stage heat removal at single stage air flow or 80% of 2nd stage airflow? If you could clarify this too, I would be willing to try it after #7 above.

No, this would get you 80% of first stage airflow with 1st stage heat removal. This is so you can have a cold coil and long run times. I fear that this is a waste of time. If you lack the jumper from BK to R and you are locking out second stage by having single stage stats and telling the zone controller to use the t-stats for staging then you are kinda already at this point. The only difference would be that it would be putting that air into both zones always if you have NO dampers.

I am sorry JNo, but I do not think my ideas are going to be much help. It looks like you have already in one way or another pursued them. I guess if it were me, and I was really hating the humidity, I would hook up that BK to the zone controller and way reduce my CFM/Ton. If it screws the system up then replace the destroyed 5 ton outdoor unit with a 4 ton and begin again.

On the bright side, you have a really good 4 zone controller. How about you run duct to your workshop or garage and add a third zone since it seems like you have plenty of capacity. The only cost at this point would be the duct and t-stat.


I'd need the exact coil model number to show you the ratings, but per the performance data for a couple of 5 ton XL20i system with 100k VS furnace I picked off the list at random, the 1st and 2nd stage total and sensible capacity are pretty near a 50%/100% split.

Thanks for the back-up, Mark. As I am not in the HVAC business I was unable to provide this to beenthere. I actually tried to get your input on my system. I called your company, but they did not want to give me your cell number as I am out of your service area. I even went so far as to have another professional member try to contact you, Irascribe. I have appreciated your writings on this forum as they helped me find a good contractor and have a system I am thrilled with. Thank you.

[BobbyBJr]

Thats why you don't use Y lo with the 16i.

On other brands. If you use a dehumidistat, then Y lo is 50% or less(depending on brand).

We got a bulletin on the wiring differences between the 16i and 20i from our distributor because of the different capacity split of the outdoor units and so many being wired wrong in our area. The OP appears to have a problem as much with the zoning and controls as anything, since one zone appears to be working well.

[beenthere]

We got a bulletin on the wiring differences between the 16i and 20i from our distributor because of the different capacity split of the outdoor units. The 20i uses two compressors while the 16i just unloads the scroll compressor. We don't do as much Trane as we used to, so I don't have the bulletin handy, but I'll post it if I find it.

Thats one of the reasons the 16i has such a high SHR.

[beenthere]

I'd need the exact coil model number to show you the ratings, but per the performance data for a couple of 5 ton XL20i system with 100k VS furnace I picked off the list at random, the 1st and 2nd stage total and sensible capacity are pretty near a 50%/100% split.

I printed off a couple of pdf files of the extended performance data for high and low speed of a 5 ton XL20i matched with a 95k XV95 and a slab coil. Results with an A coil are pretty similar, just slightly lower capacity.
Tables are generated with Trane's "Electronic performance data" utility on Comfortsite.


Thanks Mark.

I see that on that unit. They run the blower at 40% to get the lower capacity. And a reasonable shr.