Replacing HW T87-F with HW RTH2300-B1012 - won't power up
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Replacing HW T87-F with HW RTH2300-B1012 - won't power up
OK, the system is a Burnham gas fired boiler, single zone system. I have a heat pump/AC system that runs on it's own thermostat. This is a 2-wire system. Original thermostat was wired Red wire to W and white wire to R. I wired it the same way to the new HW thermostat. New batteries, checked with a headlamp and they are blindingly bright. Can't get the thermostat to even turn on. Does this get power from the boiler somehow or is it only battery powered?
I checked the boiler manual and the wiring there, the thermostat wires trace down to the R and G terminals on the boiler control panel.
I did notice that there is a diode or something jumping the R and Y terminals on the back of the T87-f, but it appears to be "factory". Any help would be appreciated.
I checked the boiler manual and the wiring there, the thermostat wires trace down to the R and G terminals on the boiler control panel.
I did notice that there is a diode or something jumping the R and Y terminals on the back of the T87-f, but it appears to be "factory". Any help would be appreciated.

#2
That thermostat does not need furnace/boiler power to turn on.
You can remove the thermostat from the base to program it.
That "diode" thing on the back of the old thermostat is a resistor and is used for heat anticipation.
You can remove the thermostat from the base to program it.
That "diode" thing on the back of the old thermostat is a resistor and is used for heat anticipation.