Furnace Won't Go On

clothdog · #1 Oct 13, 2006, 11:34 AM

THE PILOT LIGHT IS ON BUT THE FURNACE WON'T GO ON. i TURNED THE THERMOSTAT WAY UP AND IT STILL WON'T GO ON. THE CIRCUIT BREAKER IS ON. THANKS...wE'RE FREEZING HERE IN bUFFALO TODAY

labman · Oct 13, 2006, 01:02 PM

You do have it switched to heat? First step is to make sure the thermostat is getting power. If you have A/C or a fan on option, try one of them and see what happens. If they are dead, the 24 volt transformer may be too, or at least the fuse for it.

If you have power, try jumpering the R and W terminals at the furnace. If that gives heat, the problem is the thermostat or in the wiring. If not, and you have a forced draft, the motor or its relay could be bad. The gas valve could be bad.

NorthernHeat · Oct 14, 2006, 09:27 AM

Quote:

Originally Posted by clothdog

THE PILOT LIGHT IS ON BUT THE FURNACE WON'T GO ON. i TURNED THE THERMOSTAT WAY UP AND IT STILL WON'T GO ON. THE CIRCUIT BREAKER IS ON. THANKS...wE'RE FREEZING HERE IN bUFFALO TODAY

Age efficiency and brand of furnace? Since you say it is a standing pilot, I'm going to "assume" it is natural draft (70+%). If you have 24 volts from R to ground and jumping R-W at the furnace still does nothing, check for an open limit device. There can be many types of these safeties (sorry I can't be more specific than that) Spill switches, fusible links, or main limit. Many of these can be reset by pushing a small button on the device. Beware, if you reset one of these and the furnace works, you still need to find out what caused it to trip. Plugged flue pipe? (Birds nest?) Flames rolled out the front of the furnace? (Cracked heat exchanger?) It is better to call a qualified tech' than to risk your families life....