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Baseboards hot when boiler is heating DHW water

DeanG
DeanG Member Posts: 16
edited December 2023 in Oil Heating
Happy Holidays! I have noticed that when my boiler is heating direct hot water that one zone with radiators is getting hot too without a call for heat. 

 (logamatic status shows water symbol on my Buderus which tells me it is heating water until it satisfies my DHW temp)

All of my circulator pumps have been replaced with new taco Internal flow check models except for the circ pump for my DHW. 

Does it make sense for me to replace this old taco circ pump so I get one with an internal flow check to solve my problem? The zone that is getting hot already has an IFC so I’m trying to understand how it would get hot from this as there hasn’t been any call for heat for 24 hours from that zones thermostat and I verified the taco relay is working correctly. Thanks for your advice as I’m learning.

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,381
    It make no sense to change the DHW pump. That pump is not the problem.

    Sometimes with multiple zones you can get "ghost flow". The flow checks in the pumps are supposed to stop this. Ghost flow is exactly what you are getting when a pump from a different circuit causes flow in another circuit.

    There are several fixes:

    1. remove the pump on the circuit with the ghost flow and make sure the check valve is seating properly (maybe just replace the check valve) and that their is no debris in the pump or check valve.


    2. Remove the check valve from the pump and install a regular "flow check valve" which is a weighted check valve in the piping near the pump.

    3. Install a zone valve on that zone. When a zone calls for heat it starts its respective pump. With a zone valve the thermostat would open the zone valve and when the valve opens it will start the pump.


    Has anything else changed? Did the system work without ghost flow previously?




    Is it just the one zone that is having ghost flow?
  • DeanG
    DeanG Member Posts: 16
    edited December 2023
    Thanks for the advice. Everything has worked fine prior to this. 
    One zone is heating up and the rest are fine. I replaced the zone circ pump that is getting ghost flow with a brand new taco ifc pump a few days ago and that didn’t resolve the issue. Upon further inspection that pump is actually stuck running without the taco relay lighting up so that may be my issue actually. I thought the vibration was another circ pump but I can hear this one going not intentionally 

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