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Honeywell SV9502 Smart Valve

Schnidly Member Posts: 17
Own a 1999 Armstrong Ultra SX90 Gas furnace. I did all my voltage checks and got 24 volts on the connectors. What is happening is that the hot surface ignitor glows red, the pilot comes on briefly then shuts off through a few cycles and the main burner does not light. Is this a flame sensor rod fail? I get 3.4 ohms of resistance through the ignitor and this according to what I read is normal. Can I check the black wire on the flame sensor rod to ground? If so, what I should I be getting for a reading? I check the black wire to the flame sensor to ground and I get an open reading, infinite ohms on my meter. Could the rod just not be grounded properly? Please advise.


    JUGHNE Member Posts: 11,021
    You may have a dirty flame sensor rod.
    It is attached to the HSI as one unit.
    The HSI is quite fragile.
    If this is the original since 1999 you might consider changing the entire HSI/sensor assembly.

    The flame sensor is insulated from ground.
    It sends a signal back to the module thru the flame.
    You need a good ground connection on the burner.
    That might be the simplest fix, just remove and reconnect the ground wire.

    One quirk (failure) of this gas valve was to turn on the main valve and pilot valve at the same time, this would often blow out the pilot flame and retry 2 more times then lock out.
    If you have the door off and sit in front of it when this occurs you will know it.
    If this happens you need a new gas valve.