furnacehvac
I have a Rheem furnace in my house. It recently stopped working.
It is the type where the pilot is not always on. Anyways, the ignition will kick in, and the pilot lights just fine. However, the spark ignition just keeps going and the main burners never turn on.
Unless I am mistaken, this furnace does not have a flame sensor, so I'm at a loss for what could be the problem. Any help is appreciated!
I finally found some time yesterday to take a closer look at the furnace.
I started by measuring the incoming gas pressure using a gas pressure gauge. I found it to be 6 WC (inch water column), which is well within the acceptable range specified on the furnace.
Next I took a closer look at the spark gap itself, and watched closely as the spark was generated. I even recorded the spark with my video camera, which allowed me to zoom in fairly close. This is when I noticed a bit of carbon buildup on the electrodes, and wondered if it could be that simple...
I grabbed a bit of 220 grit sandpaper, and cleaned the electrodes up a bit. steel wool is probably the tool of choice for this job, but I didn't happen to have any on hand at the moment (not yet unpacked).
After testing the pilot ignition a few times, the problem seems to be fixed. We had a cold night last night, and the furnace fired up fine all night. As I write this, the furnace has just cycled successfully yet again.
I found this YouTube video from Grayfurnaceman that describes the problem exactly, and says that the only solution is to replace the assembly. I'll be replacing the pilot assembly once the weather warms up, so we'll see if that solves the problem.
Check to make sure the wiring for the flame sensor is properly connected, and the wire is not damaged. If that all seems good. Replace the flame sensor. If the pilot is not proving, it's almost certainly because the flame sensor is not detecting it.
Flame sensors do go bad, but are typically a cheap replacement. However, it looks like the sensor in your furnace is part of a pilot assembly So it will be a bit more expensive, and a bit more difficult to replace.
Best Answer
There is a thermocouple, the thing that is glowing red in the pilot light that tells the furnace the pilot lit. If that is bad it will continue to try to light the pilot. They are not real expensive but that would be the first thing to replace.