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Baseboard Heater only works when another unit turns on the heater

IanAK Member Posts: 4
Hi there,
My house is heated with a baseboard heater. It's a triplex and each unit has thermostats. The thermostat is an analog Honeywell. A few days ago, i was working out at home and accidentally turned the heat switch to off (figured out next morning, freezing). And after that, the heater at my unit only works when the furnace is on. That means, even though i set up the thermostat to 90F, the furnace doesn't turn on. (the furnace is in another unit) and if another unit sets up the temperature higher and the furnace is on, then the baseboard heater in my unit works.

Please give me an advise! Thanks :)


    HVACNUT Member Posts: 5,025
    edited May 2019
    Shutting off the switch might not have had anything to do with it.
    Just guessing but it seems the zone valve supplying your unit is stuck open but not so much as to close the end switch and start your heat. Now because yours is stuck open, whenever another unit turns on their heat you get heat as well.
    It would be helpful to post some not too close pics of the thermostat, switch, boiler, and boiler controls.
    Just for S&G, turn down the thermostat to 50° and shut off the switch again for 5 minutes then turn it back on and raise the thermostat 10° above room temperature. Hail Mary.
    We'll know more with some pics.
    Alan (California Radiant) Forbes
  • HomerJSmith
    HomerJSmith Member Posts: 2,143
    edited May 2019
    I assume you mean boiler and not furnace. There is a difference.
    I think that the thermostat is working ok and is opening the zone valve, however, the end switch is not turning on the boiler. You can test this by jumping the end switch with a jumper wire, just make sure that your thermostat is calling for heat. The boiler should turn on and if the zone valve is open, you should have heat in that apartment. Make sure that the other 2 apartments are not calling for heat. What is the manufacturer and model of your zone valve?
    The end switch is connected to the boiler's circuit with a wire and that wire must not have any breaks in it or loose connections.