Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss U/F heating directly off a combi in the Central Heating Forum area at UKPlumbersForums.co.uk.

  1. chris watkins

    chris watkins Plumber

    Has anyone taken an under floor heating system straight off a combi or heat only gas boiler without using a blending valve or mixing header ?
    If so, did it work & was there any problems with the boiler controlling the water temperature?

    The boiler operating temp range can be fixed (heating side only) to 50 - 30deg C on the board.
    I know the limitations on the boiler pump but it is a very small circuit & there in maybe another problem as the heating load at -3degC is only around 3.5kW, the boiler has an anti-cycling timer which hold it off for 3mins but just not sure if this will work correctly.
    Help Please, thanks Chris.
     
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Is that the only circuit eg no rads ?
     
  3. chris watkins

    chris watkins Plumber

    Yep, it is just a 1 or 2 coil U/F system in a Summer/games room. Bit overkill IMHO but thats what he wants.
     
  4. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    its going to cycle like a mother i would close tee it

    if you can set it up right eg the temps cant see why not just label the temp knob as do not touch due to under floor etc
     
    • Informative Informative x 1
  5. chris watkins

    chris watkins Plumber

    I have been told you can fix the Temp with a jumper on the board. So at least that won't be a problem.
    Thanks Shaun
     
  6. bogrodder

    bogrodder GSR

    What’s the size of the area that needs the heating Chris?
     
  7. Rob Foster

    Rob Foster Top Contributor!!

    Some on here might say - as I have been told myself - thats DIY !
    I think the concept is good -
     
  8. chris watkins

    chris watkins Plumber

    Approx 8x4m stand alone building.
     
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    diy?
     
  10. chris watkins

    chris watkins Plumber

    I remember doing a job in London must be at least 25 years ago which was all underfloor, it had 2 large blending manifolds one on each floor, fed by a heat only Ideal iMax condensing boiler on which you could set the operating temperature to give a maximum of 50deg C flow.
    I couldn't understand why the boiler was then set up to give high temp water which then had to be blended down to give no more than 50 at the manifolds, it didn't make sense as boiler could have been in condensing mode all the time.
     
  11. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Separate hot water boiler ?
     
  12. chris watkins

    chris watkins Plumber

    Yes, electric cylinder for some reason, it was a large doctors surgery so not much required.
     
  13. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Sometimes it's due to them wanting a back up eg heating goes off they can still work etc
     
  14. Chalked

    Chalked Plumber GSR

    Did some shops with a combi and just underfloor, about 5 years ago.
    No blending valve and using the combi pump.
    I service them every year and so far, no probs.
     
    • Like Like x 1
  15. chris watkins

    chris watkins Plumber

    Thanks Chalked, what was the boiler & did you limit the temperature range ?
     
Loading...
Similar Threads - heating directly combi Forum Date
Central heating not working Gas Safe Register Forum - Public Forum Sunday at 3:18 PM
Baxi Neta-tec works on water but intermittant on ch heating Central Heating Forum Saturday at 12:17 PM