Gas and Oil Home Heating Furnaces - Thermostat Question

I've got a wall heater with fan using a wall mount mechanical thermostat that uses 4 wires and 1 ground. No clue or hint of maker of the thermostat, other than its labeled double pole M602. The wires are connected to I guess 2 transformer piece, each with a red and a blk wire.

No clue to what wires control what. Surfed the net and looked at books about wiring, played alittle with the wires....shock.

Need help hooking up a programable thermostat.
Thanks.

Hello: Sam

My guess would be the wall heaters fan can be used independently from the heater. A fan only for summer months and a fan run by a temperature relay.

If this is the case, one of the two of the wires should go to the transformer and another to the gas valve. The other two should be wired to the fan.

I would suggest you trace the wires from the thermostat to the heater and determine which wires go where. A continuity and or voltage check at the thermostat should help determine which wires go where.

Not all programable thermostats are designed of generic useage. be sure the one you purchase is compatible to the heater.

Several other resident heating and cooling professionals, replying within this forum, may have alternate or additional helpful information, suggestions and advice.

Check back several times for additional replies.

Regards & Good Luck, Forum Moderator.
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Hi Tom,

Thanks for a reply. I should have said this is an electric wall heater and the fan comes on when the heat comes on. Unfortnately, I'm not able to trace the wires. Unless you know of a gadget I could use. :)

I suspect that you have a line voltage t-stat for the wall heater and should be replaced withline voltage only with correct amp rating

What gauge are the wires? If they are a large gauge (10 or so) then you have a line thermostat, and can only replace it with the same type. If they are little tiny wires ( :) ) then you can replace the thermostat with a programmable low voltage one. But I've never seen a low voltage thermostat that has a ground wire, or that has shocked me.

Definitely, heavy gauge wiring, the type you see in a new homes being built and waiting for an electrican.

Will check out the t line voltage and line thermostat. Thanks for your thoughts.

Guys, thanks for your help. I do have a line voltage thermostat. Took a while for me to find a place that sells a timer. :)