Gas furnance- Won't Stay On

Ren Pavich

if the tstat is a mercury type stat maybe the anticipator isn't set to the gas valve. are their any pressure switches on the furnace? I've seen bad high Limits on furnaces that will operate that same way can you test the temp at the limit to see its opening at the right temp? Test with a meter after the unit shuts down to see if its open. If the furnace has a bad heat exchanger and is 6 years old it should have warranty on the exchanger.

garyppi2488018

Gas furnance- Won't Stay On-Check Just About Everything!!

Hellow and please help me!! A licensed HVAC friend is helping me fix my heating Sys. We have replaced the -gas valve,flame sensor,& control board units.Traced back all wires for shorts,checked ventilation,thermostat Etc.We did find a defective switch under the fan motor, that we are replacing. part # 47-22860-01 - could this be what makes the burner turn off after a proper start up .Every thing comes on but after the fan kicks on the burner shuts of after about 15 Sec.The Sys is only 6 yrs old and is clean.Stoped working 1 week ago and hasent has any other problems before My friend has 20 yrs experience and has never seen this. Here is more Info. Weather King Gas Furnance. Model : 80PJ05EARO1 Ser : EB5D302F390206361 Please give me you ideas to fix the problem or comments. Thanks Again Gary

Dale

some guesses

I think weather king is a Ruud badged furnace. I would think this is fairly straight forward with a schematic and a good VOM, if the flame stops some gas or electric input or output is stopping or there may be a mechanical failure in the valve. I would see if the high limit is opening, a hole in the heat exchanger near the limit could give this symptom. Checking the gas inlet and outlet pressure to the valve with the burner on is always a good idea, perhaps the flame sensor is getting a low signal. A microamp reading is the way to tell. Sometimes the blower amp draw loads the circuit board enough to drop other 120V inputs. Good luck.