I have a natural gas boiler and a pellet stove. I have a Honeywell programmable thermostat (2 AAA Batteries) that I have used independently with both of these systems. Switching from one system to the other requires rewiring the tstat. Can a buy some kind of switch, preferably from Lowes or Radio Shack, that I can use to switch which system is being controlled? Preferably something I could put inside of a wall remodel electrical box.

Why? There are a number of variables. I sometimes have lots of pellets or none at all. When it is very cold, I prefer to use both (pellet stove always on), but when it's warmer, just use the stove on the Tstat. Being able to switch without rewiring would be nice!

  • Are both systems on the same 24VAC control transformer, or on different ones? Also, how do they feed the ductwork? – ThreePhaseEel Apr 30 '16 at 18:15
  • Transformer: how do I find out? Boiler has radiators / water - gravity feed. Pellet stove has a blower built in - it's in the living space. – Jess Apr 30 '16 at 18:32
  • you'll have to trace the thermostat wiring. Can you post photos of how the wires are hooked up, both at the T-stat end and at the stove and boiler ends? – ThreePhaseEel Apr 30 '16 at 19:31

You just need a multi pole switch. If you are using a T-stat that uses batteries you may only be using two wires to actuate the circuit.

In that case get a double pole double throw switch. (If you are using three wires you will need a triple pole double throw.)

Like this one.

Connect your thermostat to the center terminals and the boiler and the wood burner to each of the other pairs of terminals. Then switch back and forth to your heart's content.

Good luck!

  • Thank you! Yes it is just 2 sets of wires for each. – Jess May 1 '16 at 2:39

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