Rheem Classic 90 Won't Light On Its Own. Help!

Old 02-20-13, 02:51 PM
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Rheem Classic 90 Won't Light On Its Own. Help!

Rheem Classic 90 Gas Furnace
Model: RCBA-3765GG17XI
MFD: 10/2004

My furnace will only light up if I push and hold the button in the lower half. When I tested it, the circuit board signaled 2 blinking green lights. The ignitor glows attempting to light the flame, but it won't catch on it's own. I have been able to get the flame to light twice by blowing in the flame box area when I saw a spark while the ignitor heated up/glowed, but not on its own.

Thus far, I've tried:
Cleaning the flame sensor
vacuuming/cleaning off areas around and inside the furnace
flushing out the drain pump (which leads directly into my sump pump drain)
resetting at the circuit breaker box
turning off furnace's gas/power supply then restarting

I am beginning to suspect that the ignitor needs to be replaced and have attached a picture.

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Last edited by NGUGen; 02-20-13 at 03:33 PM.
Old 02-20-13, 04:48 PM
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The ignitor looks fine.

The button you are pushing is designed to prevent the furnace from operating if the fan compartment door is not in place.

My suggestion is to replace the fan compartment door and remove the burner compartment cover.

Observe carefully the sequence of events that occurs when you turn up the thermostat and report that sequence here in order and in detail.

A furnace doesn't just turn on. It goes through a sequence of events before it produces heat. By describing that sequence we can probably help you determine how far your furnace is getting in that sequence, which helps determine what the problem might be.

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