Underfloor heating not heating

Joined
26 Oct 2015
Messages
114
Reaction score
1
Country
United Kingdom
Hi all . All of a sudden my ufh doesn’t get up to temp . Boiler fires up but between the boiler turning off when it reaches temp ans then the 2 minute off and then off when it reaches temperature , the return from the ufh is so cold , that the flow to the manifold never gets hot enough and hence the cycle goes on . Turned on my radiators to get the water hot and then turned on one loop of the underfloor .its only a small room maybe 8x10ft and 10ft at best from the manifold so it’s not a long run . Flow now stays hot ish but even with the pump on 3 and the flow meter showing 4ltr/ min the flow temp never gets above 45 and the return 35 , mixer valve is set to max . I know 45 is supposed to be aboht right for flow BUT I should be able to have it higher and the return should also comeback hotter which it used to do . Seems even though the flow is showing as ok there is actually some restriction somewhere .
Ideas ? Mixing valve ? Air ? Many thanks
 
Sponsored Links
Just as an addition , the flow temp just before the pump is really hot so it’s much higher than the 40 odd that’s getting to the manifold
 
If you can't get it any hotter and there is correct flow through the circuit and the temp into and through the pump is 60deg + from the Boiler, then it's got to be the mixing valve.
 
3981618B-EC00-4904-8024-FE240A5151A2.jpeg
Well up to the pump it’s hot , coming out it’s not if that makes sense..you can feel when the boiler comes on as the pipe before the pump cools a little then gets almost too hot to touch when the boiler fires up . To the right of the pump at the Manifold there is hardly any change this is the setup
 
Sponsored Links
The temp at the gauge at the red valve to the right of the pump used to go as hot as can be , now it won’t get above 45 at best if thst
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top