Underfloor heating

  1. atomant48

    atomant48 Member

    Messages:
    766
    Salisbury UK
    question for the experts we have underfloor heating in some of the downstairs- all done with new slab floors etc last year so I’m happy the insulation etc is done right. The kitchen (about 5mx5m) struggles to keep about 20 deg when it’s proper cold outside.

    The system is set to about 50deg for the water (reading off the manifold gauage) and I’m reluctant to go much higher as I “understand” there is risk to the slab if it is too hot. The floor is latex then covered in karndean.

    It is running off a grundfoss UPM3 pump and I have determined from the manual that it’s on the lowest (presumably) flow setting PP1 as per the pic below.

    My question (finally got there !) is whether I can simply select a higher flow (PP2 or 3) without risking damaging the pipework? Any of our plumbing experts use these pumps ?

    Thanks in advance !
     
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  2. brightspark

    brightspark Member

    Messages:
    27,427
    Location:
    yarm
    if you increase the speed of the pump more than needed all it will do is spin the water round in the pump body and make a racket it wont flow through the pipes any faster . you generally set them on high speed and turn them down till they run quiet
     
  3. hotponyshoes Member

    Messages:
    1,510
    Location:
    Somerset. Uk
    Is there a manifold on the downstairs system with flow controls?
     
    brightspark likes this.
  4. atomant48

    atomant48 Member

    Messages:
    766
    Salisbury UK
    Thanks for the replies.

    Yes I think there is - pic attached. I assume the glass tubes are flow indicators and the solenoid looking things are adjustable flow valves ?

    I’ve also shot a pic of the gauge - it is actually at about 52 deg with the ED2D7296-DFCB-4274-A46E-4D8A18623E78.jpeg F626B665-5975-40CA-BCD1-036FEB78F030.jpeg 0ED359C9-3423-4CB4-B63E-534EFE1878C3.jpeg 7151BB4E-1470-4E00-BAC1-E0234A30F8B9.jpeg C57CD644-DC97-4E48-AA30-EC0DAF1EB55F.jpeg parallax.
     
  5. daleyd

    daleyd Member

    Messages:
    6,118
    Location:
    Wrexham, North Wales
    We find with ours that it needs to be on longer than a radiator system, if you have it coming on at the same time as the rads then it may just need more time :dontknow: The lower temp is offset by the fact it’s on for a longer period.
     
    Parm likes this.
  6. Domdom Member

    Messages:
    69
    Location:
    UK, Warwickshire
    We have it in the new part of the house and I find it best to leave it on all the time. We set 18 degrees for night and 20 degrees for the day, starting about an hour before we get up. You should treat it more like a storage heater to get the best out of it. I run it at 40 degrees on the manifold thermostat and the pump is set to be as fast as possible without being noisy, i.e. turn it full up and then wind it back until it runs silent.
    I did have to be careful in the snug though. This is carpeted unlike the kitchen/ breakfast room and I had to get special underlay which passes heat. Most underlay is designed to insulate which defeats the object of the underfloor heating. Wasn’t cheap either
     
    Sean likes this.
  7. atomant48

    atomant48 Member

    Messages:
    766
    Salisbury UK
    Yep all noted. Should have said at the start it is set to 20 manual on the stat and runs all the time.
     
  8. Sean Another 602 fan

    Messages:
    1,152
    Edinburgh
    you can reduce the flow on the other circuits which may force more flow round the problem circuit, take it there's a room stat and its working and not situated somewhere warm or in the sun etc

    Oh and the correct room stat working the right actuator on the circuit....dont ask about that one :whistle:
     
  9. Agrismith Member

    Messages:
    414
    Location:
    Uk south east
    When I was researching I found lots of stories of rooms not getting hot enough from new being down to using electricians that arnt familiar with underfloor heating I cant remember the exact problem and never gave it much thought as mine is only single zone so fairly straightforward but if you have multiple zones it may be worth checking the wiring
     
  10. brightspark

    brightspark Member

    Messages:
    27,427
    Location:
    yarm
    looks to have 4 zones with solenoids you must have 4 thermostats presumably one for each zone or there supposed to be
     
  11. Shox Dr

    Shox Dr Chief Engineer to Carlos Fandango

    Messages:
    14,057
    Location:
    East Yorkshire
    Under floor heating should be regarded as back ground heat, it cant react fast enough to cope with the temperature fluctuations we get. Secondly heating is required to react to a sudden temp drops
     
  12. Sean Another 602 fan

    Messages:
    1,152
    Edinburgh
    turn 3 room stats to 0 and see which circuit flows at the manifold
     
  13. brightspark

    brightspark Member

    Messages:
    27,427
    Location:
    yarm
    there marked up opn the solenoids what zone does what the pilots on the control box would say when they were activated
     
  14. Kayos

    Kayos Member

    Messages:
    4,938
    Location:
    Yorkshire
    Just swapped 2 of them pumps on an under floor system, dead in 12 months

    Use a Wilo 6m and set it to underfloor mode, usually 4 to 5 is enough

    55 is fine on the mixer but you need a 7 degree difference between flow and return so that is how you should set it up
     
  15. atomant48

    atomant48 Member

    Messages:
    766
    Salisbury UK
    There are 2 stats - one in the hallway and one in the kitchen. Hallway works fine but it’s in the middle of the house so I guess it doesn’t work as hard. Kitchen and utility (adjoined) run off the same stat which now makes me wonder why there are 3 circuits feeding them. I’ve got a photo of the pipes before the screed went down I’ll take a look how the circuits ran.
     
  16. Agrismith Member

    Messages:
    414
    Location:
    Uk south east

    If the floor areas are too big they may run two loops in a single zone this is what mine has as its one large room
     
    Sean likes this.
  17. atomant48

    atomant48 Member

    Messages:
    766
    Salisbury UK
    79FE53FC-3F9E-48E0-BF2A-5026E6F5B287.jpeg Seems to be as above - just broken the room into several areas.

    So I guess the question is can I simply increase the flow on the pump without damaging the pipework ? It’s a great point above about setting the flow to give a certain temp drop flow to return but I can’t see a way of measuring the return temp.
     
  18. Kayos

    Kayos Member

    Messages:
    4,938
    Location:
    Yorkshire
    Check your pump hasn't died, grundfoss ups3 are the worst pump they ever made

    Ufh has constant pressure, I use 6m pumps and reduce them down so they are not on max all the time, Wilo have a nice display for this

    Just measure the temp of the return pipe, the system should have been designed with a delta T of 7 so in theory it doesn't matter what the flow temp is as long as the return is 7 degrees less

    Ufh is not some complicated black art, its pipes with water in it......
     
    daleyd likes this.
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