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Thermostat off, burner runs anyway

I'm new to steam heat. This is a 5 year old Burnham, single pipe system. Hot water is an independent electric heater. Ever since putting the programmable Honeywell thermostat to 'off, the burner still fires up and runs a few minutes at a time, more than once a day. Is this normal?


  • STEVEusaPA
    STEVEusaPA Member Posts: 6,506
    Nope. If you disconnect the thermostat at the boiler, does it still run?
    If so, you may have damaged the control when installing the thermostat.
    If not, I would start troubleshooting the thermostat wire and new thermostat for problems.
  • SuperJ
    SuperJ Member Posts: 609
    Maybe the hot water was initially (before the installation of the electric tank) generated from the steam boiler via a coil, and an orphaned boiler control is maintaining a minimum boiler temperature? Got an pictures?
    EBEBRATT-Ed Member Posts: 15,526
    @SuperJ has a point. Was the boiler ever used to produce DHW?

    If not then follow @STEVEusaPA advise
    HVACNUT Member Posts: 5,841
    Look on the right side of the boiler. Is there a grey rectangle control? Pull the cover and turn the temp to 140.
    If its oil fired, it's not a bad idea to have the system cycle to keep the flue passages dry.