My original PSG Signature thermostats failed. I replaced them with Newell supplied RVComfort-PHP 6635A336 which work great and allow me to run single or dual compressors for both front and back. I had trouble understanding their wiring diagram so I make my own diagram which I have attached if anyone decides to install these.
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Honeywell claims that the RTH9580WF wifi touchscreen thermostat works with multistage units. Finding the correct wiring combination could be a bit of a challenge based on Chester's information. The Honeywell has connectors for C, K, Rc, R, W-O/B, Y, G, W2-Aux/E, Y2 and L. Incidentally C is required.
The Honeywell operates on 24 volt AC. What voltage does the SCS use for the thermostat?
(06-05-2016, 02:13 PM)Fulltiming Wrote: [ -> ]Honeywell claims that the RTH9580WF wifi touchscreen thermostat works with multistage units. Finding the correct wiring combination could be a bit of a challenge based on Chester's information. The Honeywell has connectors for C, K, Rc, R, W-O/B, Y, G, W2-Aux/E, Y2 and L. Incidentally C is required.
It's true, both our heater and A/C are multiple stage units.
Here is the wiring diagram for the SCS basement unit control board. Looks like 12VDC and no C wire.
Looks like you would at least need a transformer to supply 24VAC to the thermostat.
the nest is a little unique. it can do power stealing if it doesnt have a C 24v AC power wire. you can research that on the NEST forums. i have 3 nests in my house. one of them didnt have the C power so with the extra wire in the cable i hooked it up at the air handler and thermostat.
even though the nest can power steal, it has been know to cause problems with the control board in the air handler, so i wouldnt do it.
as forest said for the wifi based home thermostats, they will i think all require a 24v C power wire.
tom
Anyone know how to remove the cover to expose the wiring on the PSG thermostat?
The front snaps off of most thermostats leaving the base plate on the wall with the wires attached to the base plate.