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? 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 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 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?

[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?