Results 1 to 4 of 4

Thread: Humming TRVs after central heating system adjustments

  1. #1
    Automated Home Lurker
    Join Date
    Nov 2006
    Posts
    2

    Default Humming TRVs after central heating system adjustments

    Hi folks. Hoping you can help...

    In January we had an open-plan conservatory added with two large-ish radiators plumbed into the heating system. The (professional) plumber adjusted our 7 year-old heating system to accommodate these new radiators and the extra space of the conservatory. I don't know exactly what he did, except turn the pump speed from II to III. The heating system works well - radiators and boiler have coped with the change to the house's layout.

    Since then, two of the original Danfoss TRVs have hummed once the system is up to temperature. The humming starts quiet and becomes intrusive (presumably as the valve closes). I've tried turning down the pump to II again (at the plumber's advice) but the humming is still there (although the system is quieter generally at speed II). The only way to stop the hum is to turn the two TRVs down/off completely.

    Before I get my hands dirty and try to replace these two valves, does anybody have a suggestion for me to try and tune the system? Perhaps the plumber adjusted the bypass valve to force more water through the radiators? Should I tweak this?

    Thanks in advance.
    Ben

  2. #2
    Moderator sunbeam's Avatar
    Join Date
    Feb 2006
    Location
    lancs
    Posts
    261

    Default Re: Humming TRVs after central heating system adjustments

    i would guess the trvs are on the wrong way round,ie on the return pipe and not the flow,with modern trvs you can do this,but on older ones they tend to chatter when reaching temp,

    does the pipe on which the trv is on get warm first?

  3. #3
    Automated Home Lurker
    Join Date
    Nov 2006
    Posts
    2

    Default Re: Humming TRVs after central heating system adjustments

    Thanks for your reply.

    The two noisy TRVs are in the original system, so they weren't disturbed by the plumber. They didn't hum before the two extra radiators were added.

    The new spur to the conservatory radiators isn't close to the noisy TRVs either, so I guess the flow through them hasn't been affected by changes to the pipework.

  4. #4
    Automated Home Sr Member NeilUK's Avatar
    Join Date
    Jul 2005
    Posts
    71

    Default Re: Humming TRVs after central heating system adjustments

    By increasing the pump speed the flow and pressure in the pipework will also have changed. It could be the TRV's are in the wrong way round as prevously advised and if they are of any age then it would be best to have them replaced with a modern universal valve from the likes of Honeywell. If you can find the make/model of the TRV's you may be able to google and find out how they are meant to be installed - in the flow or return pipe on the radiator. If they are in the wrong way round then you could find that other TRVs are also incorrect and in fixing the two existing noisty valves you then find that others become noisy.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •