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My Tempstar furnace keeps shutting off. I have replaced the main electronic valve and the pressure switch. It calls for heat, ignites the furnace, runs for 5-10 seconds and shuts down. The WC is constant at .6. Suggestions?
Have you sanded flame sensor off?
The main things that shut down the flame after ignition is:
Flame sensor is coated and does nor recognize flame thus shuts unit down.
Pressure switch faults due to extra pressure in the system, but if properly vented, no obstructions, or bad switch it should be fine.
Limit trips, but this is after an extended run where it overheats.
The flame sensor trips in 3-5 seconds
Pressure switch trips upon firing
Limit trips after extended run
So, from my observations the furnace turns on, preheats, ignites, and begins running. After 5 seconds or so it shuts down and restarts. Like I said, pressure switch replaced, electronic valve replaced. I noticed the vent motor drawing nearly 3 amps when it is supposed to peak at 2.5 amp. Any other thoughts?
The vent motor drawing 3 amps is on the 120v side of operation and the flame/ignition control is on the low voltage side. So even if the motor were to amp up, as long as the transformer is still delivering 24v to safety circuit and ignition control it should be fine.
My first bet is flame sense. Sand the sensor off and if I am wrong I will remain available for follow up.
OK, I will sand the sensor.
If the flame sensor is next to the ignitor and is flat then I sanded it. Or is it the round sensor going into the side of the sheet metal chamber?Here is what happens...1) turn furnace on2) vent blower turns on3) ignitor heats up4) furnace begins to run.. 5) after 2 minutes it cycles off for 10 seconds and restarts6) after 45 seconds it cycles off for 10 seconds and restarts7) after 25 seconds it cycles off for 10 seconds and restarts8) after 45 seconds it cycles off and I get a 6+2 flashing code9) 6+2 states...Soft lockout - Flame sense lost during runCycling pressure switch or blocked condensate.
Is this a hot surface that glows and lights pilot and then pilot lights burner.
There are 3 parts bolted to the same tab. 1) the pilot gas tube2) the ignitor3) the thin flat surface that maybe the heated glow plug.The other sensor I see is about a foot away and is about 3/4 round bolted to the main sheet metal duct work where the heats get pulled from by the main blower.
This is the Honeywell smart valve.
Change the circuit board
The circuit board is contained in the valve assembly... part # 1 0 1 3 3 5 0. I changed the valve with board this morning. Furnace #s N8MPN075B12A1 A032003677
The only thing left in the flame rectification system is the pilot/sensor assembly.
This is like saying I have a noise in the tires somewhere and I changed 3 and it is still there. There is only the pilot assembly left. And also you do have the board in the valve but also the board controlling power to the valve and the inducer assembly in the blower section. You say you have changed the gas valve, the circuit board, and a pressure switch but the code is not pressure switch.
There is only one component left.