cmf 80 code 3
Posted: Sat Oct 23, 2010 1:01 pm
model: cmf 80-pg conv
serial: cmf9909-01450
just moved in and it's cold. furnace ran for a few days fine but then started going to lockout with code 3: Three flashes - the control is in lockout
because a failed ignition attempt, a gas
valve error, or a false flame sensed
during the warm up period. A false
flame condition exists when the flame
sensor senses a flame without a flame
present. If a false flame has been
sensed, the control will only return to
normal operation after the false flame
condition is no longer present.
so first i cleaned the airbox fan and motor (was caked w a 1/4 of dust/grime). Then we got a code 2 which is centrifigal switch. So i removed the intake motor. It was barely turning but not really. Some oil and a little banging around and it was running strong so i reinstalled it. Code 2 went away but code 3 came back on. So i removed the igniter assembly. The ignitor looked fine but the difuser plate has a 2 inch crack running from one side to the center. The plate is solid so i did not replace it. An hvac guy happened to be at the store when i went to get a new ignitor and he check the resistance on the ignitor and said it was much to high, so i bought a new one there. The one they sold me is nordyne part no. 902661 it's made by partners choice sku 902661a. The ignitor location is obviously a problem as the bracket is very pliable. the box says 3/16 from the burner, but i've tried many positions but still a code 3. Certain ignitor positions wouldn't allow it to light, others caused a loud ignition of the gas, but right now it's as close to original as i can tell. I found a different gas orrifice laying inside my furnace so i swapped them from a 50 which is what was in it to the 20 i found and still a code 3. Also i've noticed the ignitor runs longer if i adjust the air intake to the most constricting position limiting the air flow as much as possible.
Still the furnace turns on the intake motor. Lights the ignitor burns for 1 to 5 seconds (depending on which combination of the above tuning i do) then it cuts out. The ignitor turns off and repeats twice more. After the ignitor cuts out the third time the control module goes to lockout with 3 flashes.
I have not yet called a service tech to come over as I am typically successful with diy projects, my dads an electrician and my father in law has some experience working on similar furnaces. This is becoming increasingly frustrating especially since i can't find my electric space heater , lol.
serial: cmf9909-01450
just moved in and it's cold. furnace ran for a few days fine but then started going to lockout with code 3: Three flashes - the control is in lockout
because a failed ignition attempt, a gas
valve error, or a false flame sensed
during the warm up period. A false
flame condition exists when the flame
sensor senses a flame without a flame
present. If a false flame has been
sensed, the control will only return to
normal operation after the false flame
condition is no longer present.
so first i cleaned the airbox fan and motor (was caked w a 1/4 of dust/grime). Then we got a code 2 which is centrifigal switch. So i removed the intake motor. It was barely turning but not really. Some oil and a little banging around and it was running strong so i reinstalled it. Code 2 went away but code 3 came back on. So i removed the igniter assembly. The ignitor looked fine but the difuser plate has a 2 inch crack running from one side to the center. The plate is solid so i did not replace it. An hvac guy happened to be at the store when i went to get a new ignitor and he check the resistance on the ignitor and said it was much to high, so i bought a new one there. The one they sold me is nordyne part no. 902661 it's made by partners choice sku 902661a. The ignitor location is obviously a problem as the bracket is very pliable. the box says 3/16 from the burner, but i've tried many positions but still a code 3. Certain ignitor positions wouldn't allow it to light, others caused a loud ignition of the gas, but right now it's as close to original as i can tell. I found a different gas orrifice laying inside my furnace so i swapped them from a 50 which is what was in it to the 20 i found and still a code 3. Also i've noticed the ignitor runs longer if i adjust the air intake to the most constricting position limiting the air flow as much as possible.
Still the furnace turns on the intake motor. Lights the ignitor burns for 1 to 5 seconds (depending on which combination of the above tuning i do) then it cuts out. The ignitor turns off and repeats twice more. After the ignitor cuts out the third time the control module goes to lockout with 3 flashes.
I have not yet called a service tech to come over as I am typically successful with diy projects, my dads an electrician and my father in law has some experience working on similar furnaces. This is becoming increasingly frustrating especially since i can't find my electric space heater , lol.