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No heat this weeks case

RayWohlfarth
RayWohlfarth Member Posts: 1,671

In this weeks case, the boiler doesn't fire. Im going to go through steps I take when diagnosing a boiler issue.

Ray Wohlfarth
Boiler Lessons
Intplm.

Comments

  • mattmia2
    mattmia2 Member Posts: 11,118

    like always? not the 4th thursday of the month but only if the moon is not full and someone is showering like the questions we get here?

  • HomerJSmith
    HomerJSmith Member Posts: 2,635

    My steps: 120Vac into the transformer, 24Vac out of the transformer, Thermostat call for heat, 24Vac at the aquastat, in and out, 24Vac at the gas valve. In other words follow the voltage. Since it doesn't fire, I assume the relay and pump are, ok. Further action is based upon the findings.

  • RayWohlfarth
    RayWohlfarth Member Posts: 1,671
    edited October 2024

    @mattmia2 Exactly

    @HomerJSmith Great diagnosis method. So may you techs just start replacing parts without diagnosing

    Here is the link to the video

    Ray Wohlfarth
    Boiler Lessons
    Onyxia
  • RayWohlfarth
    RayWohlfarth Member Posts: 1,671

    @homerjsmith I meant to say so many techs just keep changing parts.

    Ray Wohlfarth
    Boiler Lessons
    ethicalpaul
  • ethicalpaul
    ethicalpaul Member Posts: 6,947

    I really liked this video, thank you!

    At a couple points during it, though, you seemed to suggest relying on the relay light to give you information, but couldn't the relay/light have failed?

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • HomerJSmith
    HomerJSmith Member Posts: 2,635
    edited October 2024

    I might add, if you put your meter probes across the gas valve, you should get 0 Vac if the coil is intact providing the input 24Vac is present. If you get 24Vac on your meter it would mean that the gas valve coil or terminals are faulty. Same with the aquastat providing the boiler temp is less than the aquastat differential setting, on a call for the boiler to fire.

    "couldn't the relay/light have failed?" I have never encounter that, but as they say, anything is possible. Which possibility has me concerned is that the Earth will spin out of its solar orbit and crash into Mars. Gasp! that would be a bad hair day. I'm giving 1,000,000 to 1 odds…Oh!…why quibble…I'll make it 1,000,000,000 to 1 odds. If you send me a dollar and it happens, I will give you a billion dollars. Sound like a deal to me. Sounds like an offer you can't pass up.

  • canstaff
    canstaff Member Posts: 3

    it appears that the 120v line to the pump relay is missing. I assume it would be a 120v pump if you have a neutral going to the relay. If there was a flow switch in the circuit I would say the pump not running would cause the boiler not to fire. First I would test for 120v on the primary then check 24v secondary. Ensure the thermostats calling for heat and be sure the aqua-stat is closed. If all that is working would check the ohms across the gas valve coil.

  • canstaff
    canstaff Member Posts: 3

    Then of course if the electric components are working I would measure supply gas pressure and manifold pressure

  • RayWohlfarth
    RayWohlfarth Member Posts: 1,671

    @ethicalpaul, thank you. That's right. The light could be burnt out and that's why I suggested checking the voltage on the aqua stat.

    @HomerJSmith LOL I'll take those odds. There was a guy in Pittsburgh with your name. Is that you?

    @canstaff No more caffeine for you sir.LOL You make some great points and I should have gone into more detail explaining it more. Thank you

    Ray Wohlfarth
    Boiler Lessons
    ethicalpaul