My Gas furnace, electric ignition, is lighting up and blowing but it'll blow out cold air. When I first started it, it wouldn't even ignite but after a quick cleaning of the burner and the gas intake assembly it'll light but just blow cold air. Any suggestions?

SOURCE: The furnace burners won't stay lit

Could be a couple things. First and easiest is to check your intake combustion air supply. If it is blocked by anything or just not enough flow, it will put out the flame. Next would be the flame sensor, usually a temperature probe near the flame front. If it's not reading an increase in temp within a pre-programmed time, it will kill the flame. It can be checked with a multimeter.

Good luck!

SOURCE: furnace burner ignites then goes out

Sound like a thermocouple, or flame sensor.
If it has flame sensor make sure you check micro amps to verify operation, because it might be the board that controls the sensor.

SOURCE: Oil Burner Will not Ignite

my burner will not light mpdel 701-crd. carlin

carl carpenter

• 82 Answers
• Posted on Jan 12, 2009

SOURCE: 16 year old Heil 75K btu furnace, some times does not ignite.

recommend getting a carbon monoxide indictor or having some one test it. with it being over 15 yrs old if checks good replace ignitor assy should fix it ok

SOURCE: the ignition light comes on, gas flames starts,

Sounds like open limit switch or roll out switch.