:eek: my furnace is blowing cold air. Last night I noticed that my furnace was shuting off when the thermostat read 64 degrees. But we had the therm. Set to 70 degrees. Now today it is only blowing cold air I have tried turning it on and off again to spark some flame? That did nothing. Now the furnace will only start by making a little sound as if its starting up for about one minute then it kicks on blows cold, then shuts off. I don't think it's a thermostat problem because it responds to me controlling it manually. My guess from other people having what's seems to be the same problem, as being the ignitor. Please help its only 5 degrees here tonight. But I am lucky to be in a condo where I have other units above below and around me! So it does not go below 58 degrees.

Also note it just dropped down to the coldest it has been all year last night when this all started. It was 8 degrees and our furnace is out off our deck (porch) and is not well insulated in the room it is in. Can get as cold as it is outside! Please help thank you.

Sorry it's so cold! My gas furnace did the same thing in November, but it was only 40 degrees here. I had the gas company come. The man was very helpful. First he said that the thermostat may need a new battery. Mine is OK for now, but an electronic thermostat does use up its battery. That would have never occurred to me, girl thing I guess.

Then we went downstairs to visit the furnace. I explained what it had been doing, and that it was not even lighting (firing up and blowing for less than a minute) anymore. He took off a panel, and used a small tool (Q-tip size) to clean the gas intake. He said that they get clogged after a few years. Then he showed me where the primer switch was. My furnace's primer switch needed to be held for 90 seconds before the ignition switch could light the gas.

As soon as the furnace was lit, we had heat. I hope that it's that simple with your furnace. Good luck.

Make and model number please!

Thanks I will check that out tonight and see if it needs cleaning
Also the make and model is: Carrier Weather Maker 9300TS

OK guys so I checked it tonight I think I pulled out a heat sensor thinking it was the ignitor but reinstalled that the ignitor would not pull out because of a tab blocking it it so I had my wife turn it on while I watched the combustion chamber the ignitor got red hot reinstalled the pilot lit and then it shut off. Maybe a circuit problem or something electrical?

It could be a device called a thermocouple, it makes sure your flame is hot enough before it opens the gas valve to let gas into the chamber,you can clean this device it is usually right in the line of the pilot it's a tubular looking small steel device, first turn off furnace so it doesn't go on while your cleaning it, use emery cloth or steel wool or very fine sand paper just rub it lightly to take off old soot be careful not to move it when cleaning because it has to stay in the line of the pilot to work properly.I hope this works for you, it has for me quite a few times.

Jack does this device have any wires running to it. Just to help me identify it better and is there more than one thanks!

It sounds like you have an igniter called a hot surface igniter, these glo for about 45 sec. and then the main gas valve opens and lites off this ,(no pilot) if the flame sensor does not sense a flame in about 7 sec. then the gas valve is shut off and this sequence is started again and may go into a lockout at some point depending on the manufacturer.
You will need to check the gas control valve with a volt meter during this time to determine if you are getting 24 volts to the valve to open it. This problem may be the gas control valve or the ignition control modual. Also recheck your model number and post the entire number. Good luck, Mike

Thanks Mike the Model number is CD5AXW024017ABAA

Oh by the way how do I check the voltage where do I check it

Thanks guys I got her going!!

Should there be a flashing red light