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Finding programmable thermostat for heat pump (2 stg cool, 2 stage heat + aux)

Finding programmable thermostat for heat pump (2 stg cool, 2 stage heat + aux)


  #1  
Old 07-10-13, 10:21 AM
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Finding programmable thermostat for heat pump (2 stg cool, 2 stage heat + aux)

I have a newer Maytag (Nordyne) M1200 heat pump with 2 stage cooling, 2 stage heating, and elec aux heat strip. From what I understand, the 2 stage heating is a bit of a newer thing (e.g. a lot of heat pumps had/have 2 stg cool/1 stg heat + aux heat, but not 2 stg heat + aux heat).

The companies (Nordyne, 3m, Honeywell) will tell me much of nothing as I'm not an HVAC tech so they defer me out. I did get 3m to tell me (or maybe it was Honeywell) that the LS90 thermostat would work. Don't want to pay that much.

I do have the manual. It basically shows the wiring for a thermostat as R, W2, O, Y1, Y2, G, C, E, L. Not sure if these descriptions are right or not below...they weren't in the manual, just the letters (I pulled descriptions from various places). I've embedded some questions too):

R -- Heating & Cooling power.
W2 (Aux) -- Auxiliary heat relay. (DOES THIS ALSO FUNCTION AS 2ND STAGE HEAT RELAY SINCE 2 STAGE HEAT? In the manual, it clearly goes to the aux heat at some point in the unit)
O -- Changeover valve for heat pumps.
Y1 -- 1st stage compressor contactor.
Y2 -- 2nd stage compressor contactor. (DOES THIS DO 2ND STAGE FOR BOTH COOLING AND HEAT, OR DOES W2 DO HEAT 2 STAGE AND HEAT AUX?)
G --Fan relay.
C -- Common wire.
E -- Emergency heat relay.
L -- Not sure what this is...heat pump reset? (powered continuously when System is set to Em Heat; system monitor when set to Heat, Cool or Off?…IS THAT CORRECT?).

What's a little confusing to me is for a heat pump, is 2 stage heat (I assume compressor is running in 2 stages) plus Aux Heat considered 3 STAGE heat? Do I have to look for a thermostat that does 2 stg c / 2 stg h + Aux heat, or 2 stg cool / 3 stg heat?

My end goal is to just get a programmable thermostat that works for a decent price, but I'd also like to get a little smarter ;-)

Thanks all.
 
  #2  
Old 07-10-13, 10:27 AM
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P.S. Can you chose to hook up or not hook up L? Some directions said that but it sounds weird to me (e.g. saying it's ok not to hook it up).
 
  #3  
Old 07-14-13, 11:33 AM
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The Honeywell VisionPro TH8320 will support the 3 heat and 2 cool operation of your heat pump.

The Honeywell Prestige and the Prestige IAQ would be your best options.
 
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Old 07-14-13, 07:04 PM
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I do NOT hook up L as I have seen them send faulty signals to the thermostat and cause the trouble light to turn on and cause nuisance trouble calls.
 
 

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