two stage furnace and thermostat

[force1]

I'm confused regarding thermostats. Do I need a two stage thermostat with a two stage furnace or just use a regular programmable one? Is there any advantage or disadvantage using either one? :confused: TIA

[BaldLoonie]

2 stage stat properly tells the furnace what to do. Allows for long low fire run times in bitter weather. Otherwise using the timer brings on high after so many minutes regardless if needed and doesn't allow for long run cycles with gentle, quiet warmth in cold weather.

[force1]

2 stage stat properly tells the furnace what to do. Allows for long low fire run times in bitter weather. Otherwise using the timer brings on high after so many minutes regardless if needed and doesn't allow for long run cycles with gentle, quiet warmth in cold weather.

thanks for the quick response, do you have any recommandation for a brand?

[acguytx]

honeywell vision pro series touchscreen 8000 series ,find one that fits your needs but the th8320u1008 for starters works for most two stage gas furnaces .i like and use them a lot.

[gary_g]

honeywell vision pro series touchscreen 8000 series ,find one that fits your needs but the th8320u1008 for starters works for most two stage gas furnaces .i like and use them a lot.

I use that t-stat for my heat pump.

I like the touch screen, plus I keep the back light on "low" all the time so I can actually see it.

[force1]

Well, I called a contractor who sells Bryant and American Standard high efficient two stage furnaces and he said that with these brands I don’t need a two stage thermostat, because the control board has a built in feature which is able to control the stages based on temperature and not on a timer. Can anyone confirm this or the guy just does not know his own product? Thanks

[acguytx]

i cant confirm that at this point but i think its not as efficient to use the system that way because if im thinking of the situation you are describing the board will initiate the second stage on run time .

so it will turn on the second stage at a timed poiunt on how long your system is working whether you want it to or not but with the Tstat as the controller you can set the point at whcich degree above room temp that you want second stage to come on .so basically it will be more efficient for you to have control of this then your system who doesnt really know you at all :)

i could be wrong but thats my take as a blind advice goes..

[force1]

i cant confirm that at this point but i think its not as efficient to use the system that way because if im thinking of the situation you are describing the board will initiate the second stage on run time .

so it will turn on the second stage at a timed poiunt on how long your system is working whether you want it to or not but with the Tstat as the controller you can set the point at whcich degree above room temp that you want second stage to come on .so basically it will be more efficient for you to have control of this then your system who doesnt really know you at all :)

i could be wrong but thats my take as a blind advice goes..

Thank you, so guess i have to insist on a two stage stat no matter what he said :eek: My other question would be is that the humidity control on these stats are good feature to have or it's not really worth it?

[acguytx]

Thank you, so guess i have to insist on a two stage stat no matter what he said :eek: My other question would be is that the humidity control on these stats are good feature to have or it's not really worth it?


i wouldnt isist if they really dont believe you need it but ask them for it and whats the down side and upsaide to having one istalled.

btw yes the Humidity control is the best part so long as these are VS indoor ecm motors.You can turn the feature off if you dont like it but it is awesome IMO.its about customizing comfort and thats the point isnt it? :D

[mayguy]

I'd ask for the two stage tstat, it will be far better in comfort than the board running it..

Not sure what your winter is like up there, but with a two stage t-stat, the furnace is going to run on 1st stage pretty much the whole time if the temps dips down in to single digit. With the longer run time (almost non-stop) you are going to get the best comfort, and quiet running equipment. If the t-stat sees that the equipment can't keep up, it will cycle 2nd stage on to help out, and then go back to 1st stage.

If you go on the board, the board is going to cycle 2nd stage after X amount of time, and then run till the t-stat no longer calls for heat, and shut down and starts over till the house temp cools down.

If your summer is hot, and humid, I'd look into the Honeywell IAQ t-stat that can slow down the blower to help remove the humidity, and go back to full speed once the humidity is below set point.

Another plus thing about the IAQ, if the installer says running a new wire will be an issue, the IAQ only need 3 wires between the touchscreen, and the control near the furnace.

[BaldLoonie]

American Standard is pure time. Bryant does have some logic that varies the time based on length of past cycles. But neither will allow more than 16 minutes of low fire.

Think of your car in cold weather? Do you constantly vary the settings between high, low and off? No, once the car is warmed up, you turn the settings to a nice gentle low and are comfy. That's what a 2 stage stat does. Why go to HIGH when the house is about warmed? That's what a timer does.

[beenthere]

Get the IAQ, not the 8000 series.

[force1]

Thank you very much for the advice I’ll get the two stage stat with humidity control. Have one more question regarding installation: the installer wants to extend the air intake pipe to the outside so the furnace won’t suck the air from the laundry room but from outside. Is this a good idea? How about lower efficiency because the air entering the furnace is really cold compare to the warm air in the house?

[beenthere]

Thats a very good idea.

That way your not drawing in cold dry air.
Plus, less chance of having sensor problems.

[force1]

Thats a very good idea.

That way your not drawing in cold dry air.
Plus, less chance of having sensor problems.

When furnace is on the 24hrs fan mode (no heat) does it draw any air from the outside through that pipe?

[beenthere]

No. Its a combustion air intake. It goes to the burner compartment.
Its not hooked to the duct work.

[mayguy]

If it's the white PVC pipe for the burner, yes you want them to go outside.

For humidity control, be sure it's the Honeywell IAQ YTH9421 T-stat, not the Honeywell VisionPro TH8321.

[ritchkeys]

I have recently installed a honeywell rct 7600 stat to my multistage variable speed goodman furnace in 2 stage with adaptive intelligent recovery activated. It is the 2nd day of operation. Prior an old white rodgers stat was used in single stage using the furnace board to change over to 2nd stage heat after 10 minutes if not satisfied. I installed this with the hopes this honeywell with adaptive intelligent recovery enabled would increase the time of low stage heat and call upon 2nd stage only if needed since it is not based on time like the furnace board. I wish the furnace to run longer on low heat to make my colonial split feel more even and comfortable. This has been my experience observing the 2nd day of operation.

With adaptive intelligent recovery enabled the stat goes into high fire in setback modes with a 2 degree differential from existing temperature and runs approx. 12 minutes in high and goes down to low stage heat for 2 minutes. It also reached setback temperature 20 minutes prior to time. Since this is only the 2nd day of operation, does the stat logic need a week to learn and readjust? As is learns and readjusts my hopes are that it will fire in low stage first and then go to high stage ifatisfied. As it learns and adjust to house conditions will the time of setback temp time be closer to actual time since it is arriving at temperature 20 minutes early? As it adjusts will I get closer to actual setback time? In single stage stat set up by furnace board gave me 10 minutes in low state and was pretty comfortable. I was hoping the logic on the stat was more intuitive. Assuming the stat may self correct, how long will it take to learn and will it be capable of starting in low stage first and swithcing to high stage if not satisfied? It is my understanding adaptive intelligent recovery is supposed to be cost effective and slowly (not fast) bring the house up to set back temperature-. It any of the above is not possible, would it be better if I disabled adaptive intelligent recovery? Would this allow my furnace to fire in low stage first and longer on setback temperature?

I should note my observations when stat is running at setpoint it does begin in low stage heat first and usually stays there the entire time for about 10-12 minutes. This even happens when temperature is raised one degree higher. I am hoping this stat will self adjust, if not I may consider wiring it as a single stage and let the furnace board fire in 1st stage as timed for 10 minutes. Please advise. Honeywell is clueless on how this works. All they can tell me is the stat makes the decisions in 2 stage.

Thanks,

ritchkeys

[beenthere]

Ritchkeys. Stop making the same post in multiple threads. This is the fourth identical post in the last 3 days. And this thread is 2 years old.

[ampulman]

Ritchkeys. Stop making the same post in multiple threads. This is the fourth identical post in the last 3 days. And this thread is 2 years old.

Thanks, Beenthere. I thought I was losing it.

Amp