I've recently fitted a Under Floor Heating system; a two room, four port manifold system.

I filled the system from the hose connection as directed (flowing water through the circuits until there are no air bubbles etc), checked pressure and so. I followed the instructional video which the supplier pointed me to with my order: video

I then connected the system to my central heating loop, and the pump is running (when required) and the actuators are firing, however there is no water flow according to the gauges at the top of the flow manifold.

So it looks like I'm not getting anyway water flow through the manifold. Is there anything obvious which could be the cause of this?

I have isolated the loops and turned on the drains out of the manifold and managed to get water to flow through the manifold from the flow line and out of the drain on the side of the manifold. So water is free to flow down the pipe, it just isn't for some reason.

  • Is there a bleeder valve above / near the circulation pumps? If they aren't self priming you need to let all the air out of them too.
    – freshop
    Sep 10, 2019 at 17:17
  • I've already bled them, no air is in them. It's as though water isn't getting to them
    – Puffafish
    Sep 12, 2019 at 10:26
  • Is there no flow in any of the lines or just 1 or 2 that are not working?
    – Ed Beal
    Oct 1, 2019 at 14:11
  • @EdBeal there is no flow on any of the loops at the manifold. I can turn loops on or off in any combination, none show any flow.
    – Puffafish
    Oct 1, 2019 at 15:11
  • Have you connected the 'end' of your UF loop to the 'return' or is it connected on the same line on the collector? (post a picture of the connection on the collector)
    – DDS
    Oct 2, 2019 at 8:24

1 Answer 1


As mentioned in the comments, I found the cause in the end: there was an extra automatic valve added between my thermal store and the UFH loop. Once I connected this to activate at the required time, hot water was received at the UFH manifold and all worked.

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