I had a wood stove installed this summer and would like to run the furnace fan to even out the house temperature. My furnace is an older gas model, and does not have a G wire going to the thermostat. Is it possible to add a switch to the side of furnace (or similar location) to manually turn on the fan when needed?

Thanks.

Yes.
Any further info requires knowing which make and model furnace so the wiring diagram can be known to bypass some thermal sensor.

When done, don't expect to feel comfortable from sending warm 76F air through cold ducts to heat 55F rooms, then sitting in a room with a return grill accepting all the cold air from other rooms. A wood stove is really to heat the one main area, not a whole house. Warm air can settle in cold ducts to condense water.

http://www.heatpro.us/service/solidair.htm

www.heatpro.us energy businessmen's knowledge

Yes, you really have to find out the MAKE and MODEL to get good answers. There IS more than one machine made.

Lennox G11 Series (yes, I realize very old).

The wood stove heats all the living areas wonderfully, I'm mostly concerned about getting a little heat down to the partial basement to prevent pipes from freezing, not to make it toasty. The air return vents are in the room with the wood stove, so in theory the exchanged air should be warm, yes I realize the air in ducts may not be as warm, but again living areas are fine. This would just be when the thermoter in the basement reads in the 40's.

Now that I know its possible to wire the fan I'll call the HVAC guys. Thanks!

Consider getting a plumber with heat tape and insulation. Heating an unoccupied and uninsulated area just to prevent freezing of a few square feet of pipe surface uses too much energy.

www.heatpro.us energy businessmen's knowledge

Yes, you really have to find out the MAKE and MODEL to get good answers. There IS more than one machine made.