I have a residential Carrier model. When heat is turned on, the blower comes on and the ignitor begins to glow, but the gas heat never fires. The gas valve is definitely turned on, and our hot water heater and oven work fine with gas heat. After the ignitor glows, I can hear a hissing sound for a few seconds, and then a click, almost like it's trying to turn the gas on, but no gas is coming out. The ignitor then goes down and then glows again and tries again, but to no avail. Any thoughts?

Obviously, it seems like it's simply not getting any gas, so I'm thinking that either something has clogged the line to the furnace, or the valve is bad. Are there any other (cheaper) options I can look at before calling a service technician? Also, the unit is 14 years old. If it's likely the valve, should I just replace the whole unit rather than pay the money to replace the valve? Thanks for any suggestions.

Norton

You have dirty burners. Rust has got inside the crossovers on the burners, blocking the gas from hitting the hot surface ignitor. Turn power and gas off going to the furnace, clean ends of burners with a brush(wire brush if you have it). Put back together and give it a try.