Flaky Furnace Thermostat
I have a Suburban gas furnace in my 4-year old 5th-wheel. The thermostat name on the front panel is "RVComfort.HP". When heating on propane only (that is, not using the heat pump), four times in the p...
Forum Discussion
BFL13,
"It seems your OEM's brain isn't working right for how it switches between heat pump and furnace."
It works as specified. If I am in heat pump mode and increase the setting by 5 or more degrees above the current room temp, it automatically turns the furnace on to augment the heat pump. That is the only heat pump/furnace interaction that is supposed to happen.
I just put a meter on the OEM tsat. With the system OFF, I have 12 vdc on the red wire's connection point inside the tstat and 0 vdc on the white wire's connection point. (I am reasonably sure these wires come from/to the furnace.) Then when I switch to "Gas Heat" mode, the white (and red) wire's connection point has 12 vdc on it, and the furnace turns on. This is consistent with the tstat's manual which says that it "energizes" the furnace via the WF (White Furnace) wire.
So I seem to have a red wire and a white wire coming from the furnace that are "shorted" together by the tstat - much as your two blue wires are shorted together by a heat-only tstat. I still think the problem has to do with the tstat I bought from Lowe's. However, as you say, things could be much more complicated than this.
Tracing wires and/or replacing the wires between the furnace and the tstat is going to be a last resort option as my furnace is in a very inaccessible area.
"It seems your OEM's brain isn't working right for how it switches between heat pump and furnace."
It works as specified. If I am in heat pump mode and increase the setting by 5 or more degrees above the current room temp, it automatically turns the furnace on to augment the heat pump. That is the only heat pump/furnace interaction that is supposed to happen.
I just put a meter on the OEM tsat. With the system OFF, I have 12 vdc on the red wire's connection point inside the tstat and 0 vdc on the white wire's connection point. (I am reasonably sure these wires come from/to the furnace.) Then when I switch to "Gas Heat" mode, the white (and red) wire's connection point has 12 vdc on it, and the furnace turns on. This is consistent with the tstat's manual which says that it "energizes" the furnace via the WF (White Furnace) wire.
So I seem to have a red wire and a white wire coming from the furnace that are "shorted" together by the tstat - much as your two blue wires are shorted together by a heat-only tstat. I still think the problem has to do with the tstat I bought from Lowe's. However, as you say, things could be much more complicated than this.
Tracing wires and/or replacing the wires between the furnace and the tstat is going to be a last resort option as my furnace is in a very inaccessible area.
