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Hot water constantly on and high temperature

Hi there, having just moved into our new house (oil boiler and underfloor heating) the hot water and UFH seem to be constantly on and at a very high temperature. We have a thermostat for the heating and UFH and both are set to off. 

There is also a main switch in the cupboard "hot water heater" which is also off. I also wonder if the pump shown inbthe picture is not powered on and is constantly pushing the water through.

I am worried the oil will be used up quickly and is the temperature anything to be concerned about ?



    HVACNUT Member Posts: 5,476
    Where are you located?
    Can you post pics of the whole system? Not too close.
    If the water temperature on the mix is over 60°C, then I'd think there's a stuck relay or something isn't wired correctly. 
    Obviously be very careful with the domestic hot water if the boiler is in fact running constantly. 

    In the meantime, the switch should shut the whole system down. 

    If you've literally just moved in, wouldn't there still be escrow money to take care of it? 
  • Sarahjtothep123
    Sarahjtothep123 Member Posts: 3
    Hi there, 

    We are in the UK (Scotland)

    Sure please see attached.

    Yes we may have some argument to take care of the work. 
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,475
    Yes full pictures from a distance..mad Dog 🐕 
  • Sarahjtothep123
    Sarahjtothep123 Member Posts: 3

    Mad Dog_2
  • Mad Dog_2
    Mad Dog_2 Member Posts: 6,475
    Those 90 degree white elbows look like Giant Shark Bites (American) that DIYers (Do it yourselfers) and Amateurs use.  As long as they don't leak...so be it.  Can you provide pictures of ALL exposed Piping, Boiler? Et cetera.  Thanks..Where in Scotland?  Mad Dog 🐕 
  • Jamie Hall
    Jamie Hall Member Posts: 22,147
    Is the boiler actually running? And -- or -- is the pump actually running? The hot water function may have a different switch -- in the US it would be called an aquastat -- which should control the hot water heating. The underfloor heating could be controlled by a different thermostat.

    There may be an electrically controlled valve to divert water to a hot water tank, assuming you have a separate one? Or does your hot water come from the same piping as the under floor heat?

    If both thermostats are off, the boiler should not be running ;-- nor should the pump.

    There should also be a main shutoff for the whole system -- and if it is off, nothing should be running no matter what the thermostats do.

    Photos are nice -- but if you can a sketch of the system showing all the piping and any valves or pumps and the boiler would be even nicer...

    My cousins live near Stromness...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    HVACNUT Member Posts: 5,476
    Where is the boiler, and the boiler controls? 
    Pic of the thermostat too, please. 240 volt?