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Is this gas control valve broken?

chris_86
chris_86 Member Posts: 53
in THE MAIN WALL
If you could find out the exact model # and make...yes gas valves can be replaced, you should have a licensed and insured person do this type of work, just a suggestion. Are all of the electrical contacts checked and clean? And in older equipment infinite readings generally indicate an open circuit somewhere...there may be other items in the selonoid cir., like roll out sensors or high temp limits somewhere...

Comments

  • Susan_10
    Susan_10 Member Posts: 1
    Is this gas control valve broken?

    My old standing pilot furnace stopped working: pilot OK, no main burner. It's a vacation house which I didn't use last winter. The furnace has never had a problem in my 20 years of use. It's probably 30 years old.

    Since it has a somewhat complicated (I'm a tech, but not HVAC) dual AC/heat thermostat, I jumped right to the gas control valve. I disconnected the (solenoid?) wires and measured across the valve with an ohmmeter: open circuit, even after attempting to bias a potential diode. Does this positively indicate a fault, or is there some sort if high impedance circuit in there (remember, almost 30 years old).

    I was tempted to put 24V directly across the control valve, but didn't. Can I do that?

    In any case, I don't think I want to repair this myself. But I don't want to be hoodwinked by a repairman. Is there a repairable solenoid or equivalent in the control valve? Since I didn't recognize a name on the valve, I doubt I can find an exact bolt-in replacement for the complete valve. But can I expect to find a generic replacement that can be fitted (with new pipe)? Or are control valves uniquely matched to the rest of the furnace?

    I suspect that a repairman is going to try selling me an entire new furnace, and I really don't want to spend that kind of money. The firebox is fine, and I do have a CO detector. I don't care about efficiency because I use the furnace so little. Do I have an option besides complete replacement or extra blankets?

  • John@Reliable_14
    John@Reliable_14 Member Posts: 171
    Susan? is that what you do....................

    to your customers as a tech? If not why would you think this. "But I don't want to be hoodwinked by a repairman". "(I'm a tech, but not HVAC)" Maybe it's me but you ask for help and insult many of us at the same time.
  • Larry Weingarten
    Larry Weingarten Member Posts: 3,821
    John...

    ...I didn't read it as Susan being out to dis all repairmen. Why come here if she cannot trust any of them? For years, I've stood with older or single women when they get automotive work, go hardware shopping, or have contractors coming over to give estimates. Just my being there and asking a question or two... or not saying a word... gets a much more thoughtful appraisal of the work needing to be done. It's not just in our industry that sales people try to push more than is needed on someone who they think cannot know what's best. Even though I have big feet ;~), I've spent some time in the sort of shoes Susan must wear daily. There are so many stories out there of people being taken for a ride. Try tagging along sometime when a woman friend or senior citizen friend goes hardware shopping. It reminds the sales people to do the right thing.

    Yours, Larry

    ps. And yes, we need some more detail on that gas valve.
  • Brad White
    Brad White Member Posts: 2,399
    Another perspective

    It seems that the gas valve may be shot from what you say, and that can be replaced probably. Let's suppose you are right.

    But the larger question is, after 30 years the unit is really beyond any reasonable median service life. Borrowed time possibly. Once you replace the gas valve, might the ignition train, control board, heat exchanger, fan motor, etc. be far behind? Yes it may last another 10 years or may go tomorrow. I hear an opportunity knocking for you.

    Current offerings are much more efficient so the option to put in a new unit might not be such a bad thing.
    "If you do not know the answer, say, "I do not know the answer", and you will be correct!"



    -Ernie White, my Dad
  • Unknown
    Unknown
    Yes you can replace it with

    most any 24 volt valve. If it is a 24 volt standing pilot model then it uses a thermocouple pilot safety so be sure the valve you get is capable of using a thermocouple tie in.

    I would however have the heat exchanger tested and a combustion test run on the unit to insure its safety after 30 years and with limited use. Having said that there is a very good possiblity that the heat exchanger may be okay. My own furnace 57 years old with a cast iron heat exchanger is still up and running with no sign of failure. In fact I still have the original blower a GE model hand wound motor still working humming along at the 96 volts I have applied to it. I converted it to powerpile many years ago after having a go with electric ignition which I have no use for. Most recent combustion efficiency on this unit was at 79% good enough for me. That by the way with 35 PPM CO.
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