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Heat pump: persistent loud gurgling

  • 13-01-2019 11:44am
    Registered Users Posts: 1 Dimmy90


    Any help appreciated pls.

    Have a nibe avcm 270, about 8 years old.

    Manifolds upstairs and downstairs. Every 6 months there is very loud gurgling in upstairs manifold. Try to vent the valves but soon after water comes out and noise doesn’t really go away. After a while the pressure in the system starts to fall, to almost 0. Then pay guy to come out. His solution has been to purge system and recharge it.

    Would like suggestions please on root cause and what’s a more robust way of dealing with the issue.

    Other relevant points:
    - the external circulation pump had to be replaced once as it broke
    - the manifold valves were manually vented until last week, when replaced with auto vent ones
    - in latest purge and recharge guy noted that the water was very dirty, which may indicate another problem
    - additional top up water hose installed about 6 months ago (where pressure drops this could be opened to increase pressure) but hasn’t been opened yet

    Given system has been regularly purged and recharged the dirty water must be from within? This could cause water to come from the valves when manually vented (dirt clogging up mechanism)? Could this cause the gurgling though which is the main problem, and the subsequent pressure drop? If so what do do please

    Any help appreciated


  • Registered Users Posts: 64 ✭✭✭ soundskin

    Firstly close all air vents in the system.
    Make sure you don't have any air vents on the negative side for your heating system (usually the return) that will draw air in and not vent it out.
    If your system is dropping pressure then you have a leak so expansion vessels and safety valves should be checked.
    A sealed system that is properly purged should stay that way without undue noise for 10 plus years.
    When the system is purged then it's best done via dedicated purge T, where hot water and heating side can be done.
    Also, try to vent your hot water cylinder.

    The problem here isn't your heat pump. It's your pipework and associated fittings.