Ducane gas furnace CMPE125U5B, will not start

Http://home.howstuffworks.com/how-to-repair-gas-furnaces.htm/printable
if you want to repair the gas valve on your own or want to check any other part which can be faulty you can just get all the information with diagrams in the link above . click it.

The gas company is the one to call and ask about wether there was a pressure drop in your area, don't attempt to test this yourself, low line pressure mAy indeed have been the problem, hold off on the gas valve until the local utility is contacted, they will in moscase do a free check up on the furnance..

Hi
on most electrical start furnaces there is an ignitor that gets dirty. a piece of sand paper will due the trick. but don't sand too much, just enough to get the dirt off.

If you can't find it, take the panel off , look for safety button that is in closed mode hold that down and watch for it to start up again. follow the click noise to it. most of the time it is mounted next to the burners.

Thanks Jeff, hope this fixes ya!
keep me posted

It sounds like it could be a dirty flame sensor. When you hear the clicks, does the flame actually start for maybe 10 to 30 seconds then flame-out as if the gas cut out? A dirty flame sensor will not register the correct flame temp and will tell the control board to shut off the gas. The flame sensor has only one wire going to it an looks like a 4 inch piece of bare, thick, aluminum wire. To clean it, use only a piece of fine sand paper. You don't want to touch it with your fingers or use any kind of cleaning solution. Any contamination residue left on the sensor will burn then coat the sensor causing it to malfunction again. Hope this helps FixYa, if so, please remember to rate my responce. Thanks.

Clean the valve at end of PCV.

Because PCV line end might have filled with slugs .

Also chance that there is no enough pressure . Check the pressure switch .

Hope this helps .

Is it out of gas ?

Hi there, nice to know that your furnace is back working.

The problem is not the valve itself, when the valve fails it stays closed all the time, just not opening.

The problem is the thermocouple that prevents the valve from opening when does not detect enough heat to say that the flame is on and burning stably.

Testing the thermocouple is quite easy, at temperature room it should return about 1khom with a multimeter.

You can find parts and diagrams for your furnace here.

Keep us updated on your problem.

Thanks.