Gas Furnace Out
#1

I have a Carrier Gas Furnace, about 20 years old. I have had some problems lately where the furnace seems to have trouble firing up when starting but eventually, it does start. Last night, the furnace went out completely. How do I safely try to relight? Help- I am a novice and it is still cold up here in Michigan

#4
some of the older carrier systems had a spark ignitor that would light the pilot at every call for heat...there was also a bimetal proving device at the pilot head...see if you hear a clicking or ticking sound on a call for heat....see if the pil;ot actually lights....if it lights and burners don't the chances are the bi-metal device is shot and needs to ber replaced......but there are other causes for your heat failure as well.....
#5
could be
a dirty pilot orifice, possible bad valve, or a few other things. it sounds as if no gas is present when the button is pushed, can you remove the aluminum pilot tubing from the valve and see if gas comes out there when the button is depressed ....still assuming standing pilot here. if so, dirty orifice, if not possibly bad valve. also there may be 2 wires coming out of the valve at the base of the thermocouple that run through a safety. it may be open, but this would allow the pilot to light, just not stay lit when button is released. give us more details
#7

Are you aware that the gas valve button must be depressed in order to light the gas pilot? hold it there for about 1 minute,and release. If it wont stay lit, polish up the thermocouple with 0000 steel wool, and try again. If it still wont hold a flame, replace the thermocouple, ..... We're all assuming you have a standing pilot (no spark box device) if you hear a tick, tick, tick don't try light anything. An ignitor generally has like a red rubberized type ignition wire, like on a spark plug wire on a lawn mower...
#8
Thanks for all the advice. Called in HVAC repair guy. There was a switch tripped that shut the furnace down. Repair guy said this happens if furnace isn't properly venting. When he said that, I immediately realized the problem. I had put a chimney cap on the day before I noticed the problem. While assembling the chimney cap on the roof, I placed the box over the top of the chimney for maybe 10 min! This apparently caused my problem.