Ask Me Help Desk - No heat, continuous blower

I've got a Day and Night furnace that has an electric ignition pilot. Normally, when the heat is turned on, you can hear the *click *click *click of the electric pilot ignition and then the blower comes on afterward. My current problem is that the pilot light now never lights (there's not even any clicking) and the blower just blows cold air all the time. It blows even when I've got the thermostat turned off! :confused:
It's cold outside and inside now and the girlfriend is pissed :eek:

Any help would be greatly appreciated.

Need more info. Is it a 90% furnace ( vented with PVC ) or 80% (vented with metal vent pipe)? If the blower runs all the time, you have a limit switch open or you had three failed attempt of the burners not lighting. You should have a small window on the bottom door on the furnace. Count the blinks of the light (two slow - pause - three fast. Code twentythree). Count the blinks turn power off to the furnace for 10 seconds and then back on, make the thermostat call for heat. What happens?

It is an 80% furnace (has the metal vent pipe). There is a small permanently open window on the left side but there are no lights on the furnace at all. There is a sticker inside the furnace that says "this furnace is equipped with a fusable element". The blower is at the very base of the furnace and pulls air from beneath the house in the garage. It might be possible for me to post a pic... sorry for the quality...
http://i77.photobucket.com/albums/j6...D/DSCN0288.jpg

http://i77.photobucket.com/albums/j6...D/DSCN0289.jpg

Thanks for the pics geomite. It gives a lot of info of what you have. With that type of furnace it sounds like a limit is open. Just to above the inducer motor(small motor above the burners) top center of the furnace is a vent rollout limit switch (small device less than 1 inch around with two wires going to it) In the center is a button push it straight down. What happens?

In the picture that I can see the gas valve, the valve is turned to the off position. I am not sure if you did this after you started having trouble or not but it will not light the pilot with the valve in the off position.
In the lower photo it shows your pilot assembly, this is a multi-purpose piece of equipment. The ceramic piece with the wire coming out of it and the large orange or red wire out the bottom is the sparker, The wire probe has to be close enough to some metal to discharge and spark, so with the thermostat calling for heat hold a screw driver against the metal of th furnace and close to the wire and see if you get a spark, if not there are several possible problems you might have, one could be a fuse in the low voltage line. It could be that the thermostat is not sending power back to the unit. It could be that the pilot assembly switch is not moving back to close the points that make the sparker spark and let the pilot light. After the bi-metal strip gets hot it will move and close some points to open the main gas valve.
I don't feel like I have been much help but it is hard to diagnose this problem without being there with a meter what check the different components.

Quote:

Originally Posted by letmetellu

In the picture that I can see the gas valve, the valve is turned to the off position. I am not sure if you did this after you started having trouble or not but it will not light the pilot with the valve in the off position.
In the lower photo it shows your pilot assembly, this is a multi-purpose piece of equipment. The ceramic piece with the wire coming out of it and the large orange or red wire out the bottom is the sparker, The wire probe has to be close enough to some metal to discharge and spark, so with the thermostat calling for heat hold a screw driver against the metal of th furnace and close to the wire and see if you get a spark, if not there are several possible problems you might have, one could be a fuse in the low voltage line. It could be that the thermostat is not sending power back to the unit. It could be that the pilot assembly switch is not moving back to close the points that make the sparker spark and let the pilot light. After the bi-metal strip gets hot it will move and close some points to open the main gas valve.
I don't feel like I have been much help but it is hard to diagnose this problem without being there with a meter wot check the different components.

Good job letmetellu. I did not even notice the gas valve in the of position.

WOw. Thanks sooo much for the help. Those two wires that T-Top referred to did go to a roll out limit switch. Being a complete heater novice, I couldn't identify it as a type of button switch. I pushed it, and now the heater works perfectly. Thanks again from my girlfiend and I. This made my week.