Crazy Erratic Furnace

[mschwennes]

I have an older Day & Night furnace that is used only maybe 2 or 3 times a year. It just started to behave a little strange. It turns on just fine in the evening. It completes a full cycle, bringing the house to the temperature set on the thermostat, and then it doesn't start again when the temperature in the house goes down. I can try to start it the rest of the evening and all of the next day, but it will not start. Until evening. Then it will run for one cycle only, again. When I try starting it other times, the igniter does not energize. If I short the R & W anytime, the igniter works and lights the pilot. Is there possibly some obvious thing I need to do or part to replace to fix * Any help would be greatly appreciated!

[Freon]

" If I short the R & W anytime, the igniter works and lights the pilot."

From this statement, it would appear the thermostat isn't "shorting the R & W" as it should when you want heat.

Check if the thermostat needs batteries. Do a few more tests by disconnecting the W & R at the thermostat (be sure to turn off power to the furnace whenever connecting or disconnecting control wires). If you can consistently get the furnace to light and run by manually connecting the R & W wires at the thermostat, it would seem the thermostat is the problem.

[mschwennes]

Great, I will try that. I never thought it could be the thermostat batteries because if I turn on the thermostat at the right time of day, it starts the furnace. But maybe the batteries are just very low. Will get back after trying.

[mschwennes]

Freon, my wife says she wants to give you a GREAT BIG KISS!

That was the problem!

So very many thanks!

Happy holidays!