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.

 

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.

 

So it's either the thermostat is a dud, or even though the batteries seem to be good, I need to try 2 more I'm guessing?

 

Definitely try new batteries first.

 

Different batteries did the trick. Thanks for the help.

 

Make sure you have gone into the Set up menu, and set your heating cycle per hour. Setting #2 to 3 for your boiler.