underfloor heating

[Danny boy]

Hi

My plumber has changed my old back boiler for a standard boiler and put in a new location. In addition he has removed my old hot water cylinder and installed a megaflo in my loft. The problem is that now my underfloor heating does not reach the desired temperature unless the normal central heating is on too. It used to work fine on its own before. I have go an electrician
to look at the wiring and both pumps appear to be working?. If anything I would of though it would have worked better without the central heating on?. If I turn the central heating off and leave the underfloor heating running the hot supply pipe temperature to the underfloor heating manifold goes right down.

Any ideas why this is happenng - has it been plumbed incorrectly?

 

[Deleted member 2053]

Difficult to know with such a scant description. Do you know if your original layout made use of relays at all?

 

[Danny boy]

Hi Graham

Thanks for the reply.Sorry for the delay.
I dont believe there are any relays in the layout.
I have had my plumber round and he is mystified. Its either got to be a
pressure problem or something wrong with my manifold on the underfloor heating. The supply pipe to it gets red hot but the reurn pipe, although hot is not as hot as it should be which to me suggests a flow problem.
The manifold (from continental ufh) has a temperature knob on it which
means you can manually adjust the temp up and down. Is it possible this is not working properly and is holding up the flow from the supply pipe?.
As I said when it is on independently it only reaches a flow temp of 40 degrees (should be 50-55), yet when I have it on with the normal central heating it gets too hot (over 60 degrees)which I am hoping is not going to damage the pipes or flooring. The pumps seem to be working fine (although not taken them apart) and the boiler seems to be doing its job?

Any help would be appreciated as getting very stressed!