UFH not working - suspect issues at manifold

[Mjward]

Hello

As per title, the 3 zones of UFH to one manifold are not working.

All is good from an electrical perspective, i.e. the room thermostats are calling for heat, the UFH wiring centre is triggering the boiler, but simply no heat is coming from the floor.

What makes analysis difficult is 1) recently moved in and had the system turn off for long period whilst doing works 2) 2 of the zones are same room, large kitchen with aga oven releasing heat.

Assuming it's an issue at the manifold, what are the things I can test for? The flow meters are gunked up, could that be the cause or indicate whole system needs power flush? It has a grundfos motor but I can't hear anything, but same motor is on different manifold and is silent but working fine, how do I test if motor actually working?

Anything else I can cross off before getting someone out?

Thanks!!

 

[Mjward]

The manifold metal bar ie the part where the UFH pipes are connected, is getting hot on both top and bottom, almost identical on both around 40c. Plastic pipes themselves not warming at all

 

[ShaunCorbs]

Open one flow meter fully open

 

[Mjward]

Thats what I've done so far. Opened one fully, closed two fully, given it some time but nadda. Same for all three loops.

I'm confused how both top and bottom can be hot if loops themselves aren't flowing. I thought only flow side was fed the warm water from the flow mixer. From the piping on mine it looks like there is a connecting (vertical) pipe from the flow mixer that is perhaps simultaneously feeding both top and bottom bars

Open one flow meter fully open

 

[MOSSEP]

It could be that you have inadequate flow to your actual manifold, your main system pump could be the issue. Isolate the other manifold that is working and see if it gives an improvement.