Underfloor Heating Unexplained Temperature Drop

[tolly]

me neither, cant see the need for that chrome bypass pipe either.

 

[Chalked]

thats return by the looks

and i guess there is non return in the bottom right end of manifold to prevent pump drawing from the return

On these, the non return is on the left hand side of the manifold. Just before the pump. The bypass works when the pump starts up an before the heads have opened.

 

[walterwhite]

I don't like it., but chalked has answered the OPs question in #23

 

[swiflee]

Thank you Chalked. Yes it is a wundafloor and everything you have said about the bypass and boiler return and non return is correct.

I thought I would have been able to at least get hot water circulating through the manifold (even with the loops closed) at the boiler temperature with the motorized valve on manual and certainly no flow temperature drop when the circulating pump is switched on irrespective of whether any controls are wired.

There is a pump in built to the boiler as its a system one.

 

[Gray0689]

It's the return to boiler. The chrome pipe above is a bypass.
It's a Wundafloor system by the looks of it.
The problem is very simple. Your motorised vslve is being held open manually.then your main pump can force water throght the loops.
Job need finishing,wiring up and testing. If you let the motorised vslve close msnuslly it will stop getting warm.

Exactly what he said
Get it wired correctly and jobs good