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bushpiggy · Aug 17, 2010, 08:18 PM

Hi, I have a mobile home and I need a 2 wire thermostat... I bought 3 digital ones and they don't work... I have to switch from heating to cooling on my furnace so, will a round 2 wire heat only thermostat work?. I believe that's how the old one worked, but want to be sure because with the digital heating and cooling thermostats the air won't shut off... getting costly on the light bill!

KISS · Aug 17, 2010, 08:25 PM

They will work. You need to connect terminals Y & W together at the thermostat. Use this connection and R. The thermostat must be battery powered.

R may be just R, R and Rc jumpered or Rc and Rh jumpered

You still need to select cool or heat at the thermostat AND the furnace.

What is the model of thermostat did you buy?

bushpiggy · Aug 17, 2010, 08:29 PM

Hi, I have a mobile home and my air won't shut off... I just bought 3 new digital thermostats for heat and cool and I have to manually shut the air off every night... My old thermostat was a 2 wire... I'm thinking maybe I need a heat only thermostat sense I have to switch from heat to cool on the furnace... Every thing is working inside and outside it just won't shut off and the temp stays in the 80's while it's running... Please tell me I'm not just a woman and don't know Jack... lol... Can't keep paying furnace guys to come out and tell me they can't figure it out because they don't work on mobile home furnaces!. Thank you

bushpiggy · Aug 17, 2010, 08:35 PM

Originally Posted by KISS

They will work. You need to connect terminals Y & W together at the thermostat. Use this connection and R. The thermostat must be battery powered.

R may be just R, R and Rc jumpered or Rc and Rh jumpered

You still need to select cool or heat at the thermostat AND the furnace.

What is the model of thermostat did you buy?

My old one was heat only and the air conditioner worked fine... my old thermostat was 38 yrs old... lol... If I remember correctly, it was a heat only round 2 wire thermo.. no batteries.. the 3 digital ones I bought had 4 wires

bushpiggy · Aug 17, 2010, 08:37 PM

Originally Posted by bushpiggy

my old one was heat only and the air conditioner worked fine...my old thermostat was 38 yrs old...lol....If I remember correctly, it was a heat only round 2 wire thermo..no batteries..the 3 digital ones I bought had 4 wires

... Honeywells

KISS · Aug 17, 2010, 09:33 PM

The wiring would have been G W Y and R and would work fine. A heat only stat will not. Connect W to Y to one wire and R to the other.

towerrigger · Dec 27, 2012, 06:26 PM

I'm going to try two diodes going from the Y and W ports to the white wire. Kind of like Y ->|- white wire -|<- W. That will isolate Y and W ports from each other but they can both still affect the white wire. You just have to make sure that the switch on the furnace/AC is in the same mode as the heat or cool switch on the thermostat. I will try this and let you all know!