Underfloor Heating Unexplained Temperature Drop

[swiflee]

Turn boiler stat up until u/floor flow pipe gives enough heat to manifold (try 70)
Is u/floor completly full of water without any air present and all valves on mani open (flows and returns)
Then find out why flow is loosing heat from boiler to mani (ceiling void open to elements or draughts, no lagging ?)
I assume new build, so maybe not fully finished

Tried turning the stat up. Makes no difference apart from the Rad circuit getting toasty :vanish:

All mani valves are open / off and there is no obvious signs of air... but the issue is the manifold flow bar cooling down. I cant fathom this part out.

Its a refurb, changing from vented to unvented with new pipework so all ceilings are down.

 

[dancinplumba]

Shut the rads off

 

[jonnyswamp]

Restriction or air in flow (or return)to mani from boiler, as said above shut rad circuit 2 port and try
If that don't work, I would disconnect flow and returns from primaries and mani and try hosing through both

 

[walterwhite]

Start again. Finish wiring it & commission it properly. Put valves on to auto. Get a plumber in is the best advice

 

[swiflee]

Thanks guys. Next step is to isolate the UFH circuit as you've said and try.

Will post the update here.

Have also got the tech guys from the manifold supplier (well known) on the case.

 

[walterwhite]

You haven't finished installing it yet! I bet it hasn't been balanced either. Flow rates for each loop need to be set. You will get heat going through to the ufh when you have manually opened the 2 port. Am I missing something or is this a wind up?

 

[dancinplumba]

Can you put a PIC up of manifold

 

[swiflee]

Here you go. Just to confirm that the white nuts on the bottom rail are all open. I just fixed them in place so I didnt lose them.

And I closed all the flow meters down except the last loop nearest the bypass valve just to see if we could get the heat across the manifold when the pump was running.

 

[walterwhite]

I've never seen a manifold plumbed like that.

 

[jonnyswamp]

Pump is running directly on the mains atm just so we could test system. The flow cools down and the return goes cold when the pump goes on.

Yes I have flow meters. When the pump goes on the little discs drop inside the vials

So if the flow meters indicate you have water movement through u/floor, problem with restriction in dedicated flow/return
Your central heating pump should supply hot water to the manifold, then the pump on the mani does the rest
If your mani pump is moving the u/floor water around then its a supply problem I would have thought
Not seeing first hand so guessing really