Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Heat turning on when outside temp is 90 degrees.

jbct99
jbct99 Member Posts: 3
in Domestic Hot Water

Hello- I have a very old domestic HW oil boiler. For some reason, today with the outside temperature at 90 degrees (inside about 80 with AC going) the boiler turned on. It was during a thunderstorm. I shut off the boiler at the switch and let it sit a couple of hours. When I turned it back on, it called for heat again and the radiators started heating up. What is going on? 😕

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 24,713

    Sounds like something objected to the thunderstorm. Can you find the connection from the thermostat or aquastat to the boiler control? If so, disconnect one of the two wires and try the boiler again. It shouldn't run. If it does, there's a problem with the boiler control. If it doesn't trace the wiring bac and see if there is an aquastat. If so, try disconnecting the wires to the boiler there. Again, the boiler shouldn't run.

    I can't get you are enough back in the circuits without knowing what other controls may be on the boiler…

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • hot_rod
    hot_rod Member Posts: 23,249

    Do you have two separate thermostats, one for heating one for AC?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • neilc
    neilc Member Posts: 2,841

    and or has the thermostat been changed over the last year?

    known to beat dead horses
  • Intplm.
    Intplm. Member Posts: 2,172

    The thunderstorm might be a coincidence and hopefully not related.

    One of the first things to look for besides some of the sage advice above is a malfunctioning flo-control valve.

    Is the entire zone heating up? Do you have a domestic hot water coil on your boiler? You might have a bad flo-control valve.

Categories