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View Full Version : 7956a856 burner won't light


racerdude
Dec 19, 2009, 10:20 AM
Has good pilot but I turn thermostat up and pilot goes out. You have to wait to relight when I open door to light it about burned my hand.This furnace has set for 2yrs and with no action.Does the burner assem need cleaned?please help Thanks Jerry This is in a mobile home

crigby
Dec 19, 2009, 11:52 AM
Hi,
Sounds as if you have problems in the thermocouple circuit. This is that thing that the pilot has to heat to stay lit. Since it stays lit when by itself and then goes out if the burner tries to light; it would seem that something is interrupting the electrical signal there in the thermostat.
I bow to a more erudite explanation
Peace,
Clarke

racerdude
Dec 20, 2009, 04:42 PM
Hi thanks for the reply,I know that when I slide the thermostat over you can hear the furnace go click to kick on the burner but you lift the lid and its blown out.I had to change it from nat gas to pro double checked all and is OK .One thing I don't like is the size of the pilot it looks way to big to me it's 2" wide by 4" blue bottom yellow ragged top Thanks Jerry

hvac1000
Dec 20, 2009, 06:11 PM
If you had to change from natural gas to LP/Propane you also have to change the pilot burner itself or the orifice only if it is a White Rodgers pilot assembly. The orifice in the natural gas pilot is way to big for use on LP /Propane gas and will eventually soot up the burner and the inside of the furnace. This is not good.

Also you will need to use a manometer to set the gas pressure for the burner since you changed it over. The correct LP/Propane pressure is listed on the furnace name plate on the furnace. Changed over many of those mobile home furnaces years ago and they are all about the same from then till now.

racerdude
Dec 20, 2009, 06:45 PM
I changed the main burner jet to the lp one and turned the orther one upside down to say lp on the end that screws in.Should I just call my lp guy to do the rest ?Iam not a furnace guy drag engines Iam not to bad.

hvac1000
Dec 20, 2009, 07:04 PM
Yes call him you need a professional to finish the job and check it all out to make sure it is correct.