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Heater makes banging noise at the top of the unit where the coils are

some_one092 Member Posts: 4
edited December 2023 in THE MAIN WALL
Hi everyone,

I am unable to sleep with this unit on and the maintenance staff has stated that there is condensation in my unit and to ignore it.

I noticed that even with the unit turned off, I can feel the heat at the top of the coils near the entry and exit of where the piping is.

Just curious how this occurs and what possibly can be done and maybe I can mention it to the staff to help guide us. Thanks


  • some_one092
    some_one092 Member Posts: 4
    edited December 2023
    HVACNUT Member Posts: 5,750
    It's almost like the zone valve doesn't close but just keeps rotating. It would have to be open if the coil is hot. And the disc sensor on the return controls the fan.

    Does the fan still run even when it's turned off?

    Is there a wall thermostat or a control on the unit?

    If the coil is hot even when it's turned off, then they need to see if there's 24 volts to the zone valve. And if so, why? I'm not 100% sure that clicking noise is the zone valve but I'd start there.
  • some_one092
    some_one092 Member Posts: 4
    The fan does turn off when the desired temperature is reached and supposedly the heat also turns off.

    Prior to this, there was banging noise but it sounded differently and the maintenance staff had replaced the steam trap. And when we turned the unit on, the coils would get hot but the fan would never come on and there was no clanking noise from the unit. They returned the next day to reattach the disc sensor you mentioned and now the heat turns on with the fan, but now we get this clanking noise.

    Also note that when we turn on cooling mode, with the fan on, there is never any clanking noise. Only with heat mode.

    I will ask about the zone valve with the maintenance staff. Thanks
    HVACNUT Member Posts: 5,750
    Steam trap?
  • some_one092
    some_one092 Member Posts: 4
    Yes, I think it's that circular joint piece on the vertical pipe. When they removed it, it was hissing with air, releasing into the room
  • mattmia2
    mattmia2 Member Posts: 9,431
    It is 2 pipe steam. that is a vertical steam trap. i thought it was hot water to begin with. The coil needs to be pitched to the return both side to side and front to back or it will trap water and you'll get water hammer. it probably shifted when they replaced the trap.