Geothermal Heat Pump Thermostat

17 years ago

I have a Waterfurnace GT HP in my new home and I am not sure that the installer has the control board set up in the most efficient manner. The staging interval for meeting temperature differentials is set to use the timer for going from Compressor 1 to Compressor 2, Aux Heat 1 and Aux Heat 2. It is set up for an interval of 20 minutes. If a temperature can't be met it stages to the next higher heat source until that temp is met and maintained. There is another setting that turns off the timer and allows staging to be controlled by thermostatic demands. I am trying to determine which setting is the most efficient. Does anyone have any experience with this?

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Comments (7)

baldloonie
17 years ago
Honeywell Vision Pro IAQ will do 2 stages of compressor and 2 stages of backup. I sure wouldn't want a timer deciding what my equipment is going to do.
tcmravens
Original Author
17 years ago
After checking the type of thermostats (all single stage) that are installed, I have a more basic question. Should this multistage GT unit have multistage thermostats?
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funnycide
17 years ago
Multistage thermostats are better because you may be able to heat your house all day with 1 stage of heat. With a single stage stat you rely on the timers to bring on second stage of heat when you may or may not need it. Also if you set back your temperature you will want multistage stat so it will bring on both stages of heating or cooling right away.
A reason single stage stats are used in retrofit applications is the existing tstat wiring does not have enough wires.
tcmravens
Original Author
17 years ago
Funnycide, thanks for the info. That is exactly the conclusion that I was coming to but could not confirm. The timer staging makes some of the rooms hotter than they need to be. I think it is also driving up my electric bill by going to the aux heat stage when it is not needed. I tested that theory and turned the timer off to let the 1st stage run. It maintained the temperature within 2 degrees most of the day until late evening when the temperature went down. I will purchase new thermostats very soon.
funnycide
17 years ago
If you have a 2 stage unit you should have 2 stages of compressor heat and also aux electric heat (maybe 2 stages). Do you have a single stage convential stat or a single stage heat pump stat? If you have a single stage heat pump stat you should still have an aux heat terminal.
tcmravens
Original Author
17 years ago
I have Braeburn Model 3000 non-programmable single stage digital thermostats. It says its compatible with single stage heat pumps. There is no setting or indicator for aux heat on the stat. The only way I know it is on one or both aux heat stages is to go to the GSHP control board, remove the cover and look at the LEDs.
funnycide
17 years ago
Was this tstat existing? It really is the wrong stat to use. Even if you say a single stage stat is okay to use, you don't have an aux terminal to bring on the elec heat.

Geothermal Heat Pump Thermostat

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baldloonie

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Geothermal Heat Pump Thermostat

Comments (7)

baldloonie

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funnycide

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funnycide

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funnycide

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tcmravens
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