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Discuss UFH Pump - Always on? in the Plumbing Forum area at UKPlumbersForums.co.uk.

  1. MJB5373

    MJB5373 New Member

    Hi all,

    I've had a Polypipe UFH solution fitted and I've got a query about the water-pump. I've asked the plumber but he's passed me onto the spark - who fitted it this way. Kinda think between them I've not got a definitive answer...so here I am asking the plumbing gurus...

    In a nutshell - this pump, I'm assuming, is constantly on. The green light is on, and it omits a sound, from the pump and the pipes. Its not pumping hot water because the thermostat isn't calling the boiler but I feel its pumping cold around the system 24/7?

    I've got the plumber and a spark coming round tomorrow, so looking to gear myself up with some knowledge

    Can anyone offer me any advice please?

    Cheers, Mark

  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    It’s always pumping which is wrong

    Also there’s looks no independent control of the zones so there all on
    • Agree Agree x 1
  3. MJB5373

    MJB5373 New Member

    thanks for that swift reply Shaun; does this photo help with regards to the independent controls.. what should I be expecting?

    Cheers, Mark

  4. king of pipes

    king of pipes Trusted Plumber GSR

    Your underfloor heating zone should have its own time and temperature controls and switch the pump off when either the stat is satisfied or the zone is not in a timed on mode I would expect to see a 2 port zone valve and a timer of some sort. Regards kop
  5. MJB5373

    MJB5373 New Member

    image.png Got ya, it’s got a Nest Thermostats connected to the boiler and a value. That pump seems to be just plugged in to perm power... should it be switched in some way
    Last edited: Jun 17, 2019
  6. Brambles

    Brambles Active Member

    With due respect whoever installed that system does not understand the concept of how a wet underfloor system operates. I would suggest that you get a credible plumber in to correct the faults, set up and balance the system properly.

    You really should not be employing tradesmen who you have to tell them the basics about what is wrong / missing with the installation they have left you with
    • Agree Agree x 1
    Last edited: Jun 17, 2019
  7. MJB5373

    MJB5373 New Member

    I totally hear you! Unfortunately, as many pre and post me. I have fallen into the trap of being told they are credible professionals and can install my solution. Getting someone else in could sort or exacerbate my issue..
  8. Brambles

    Brambles Active Member

    I can sympathise with your position - but you probably need to recognise that this is probably their first time installation with wet underfloor system
    Last edited: Jun 17, 2019
  9. king of pipes

    king of pipes Trusted Plumber GSR

    Yes the pump needs to be wired into the correct connector blocks in series with the underfloor controls it very much looks like a wiring issue . Kop
  10. MJB5373

    MJB5373 New Member

    Many thanks again, much appreciated
  11. Chalked

    Chalked Plumber GSR

    Best to disconnect the nest from the ufh. It can’t anticipate the heat and cooling demands.
  12. Jones82

    Jones82 GSR

    I think the nest has an underfloor heating setting? It certainly has a "radiator" option. I think the trouble here is the pump has a permanent live, likely from a crossed wire with the grey on the 2 port valve... assuming there is one!

    Does the pump run even when the boilers off?
    • Agree Agree x 1
  13. Brambles

    Brambles Active Member

    Nest works with both electric and wet underfloor heating systems. The latter must be properly designed and well balanced to deliver a consistent and even heat pattern to give Nest a chance to work effectively.

    The normal issue ( problem) is that the Nest Heatlinks for multiple zones are placed too close together and too close to “significant” metallic objects - multiple copper pipes or hot water storage tanks. Heatlinks should be spaced at least 300mm apart, preferably a lot more. To be fair this is an issue ( signal interference) with the Honeywell wireless systems too
    Last edited: Jun 17, 2019
  14. MJB5373

    MJB5373 New Member

    Hi Jones, the pump shows the green light always, and makes a very low sound, which is mirrored through the pipes. So I’m assuming it’s doing something... even when the boiler isn’t being called.

  15. Brambles

    Brambles Active Member

    Yes, it is. Probably circulating cold water 24 hours / day.

    Generally, Wet Under Floor Heating Systems are silent to the human ear - well they are to mine anyway!!
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