UFH and skirt heat issue - Wits end

[surfstar]

Hi All,

I have failed in my journey and I now need some advice. I have been trawling this site and the Internet for over 1.5 years to find the answer to my problem. I have reached out to three plumbers and the fitting company of the system but unable to get anyone through the door. I am a capable DIY person and will give you a breakdown of my issue and what I have done. Please be kind, pic attached to help J

I have three UFH manifolds in my house, which was renovated in stages and is very large. All manifolds work fine, all zones work fine. I laid all the pipe work myself and assisted the plumber in installing the manifolds etc.

Everything works except two zones on one manifold that feed skirting board heating in two different rooms. These two zones (Thermaskirt) did work when installed two years ago. Then suddenly there was a leak in one zone skirt, which was replaced, and since then neither zones have worked.
The zones are installed to a UFH manifold (see pic) on 6 & 7 far right.

What was done:
· For some reason the plumber installed copper from the 15mm pvc to the manifold on both zones. Number 7 is now pert, as I have replaced a section in trying to troubleshoot by removing 4x 90-degree bends.
· By doing the above the plumber used non supplied eurocones which I have replaced on zone 7 to help troubleshoot and blocking issues

What I have done.
· Replaced the flow meters on both zones twice.
· Replaced copper/pvc and angles on one zone with pert and joined from 16mm pert to 15mm pvc with a compression fitting. The 15mm runs underfloor to the skirts.
· I have bled the system multiple times isolating all zones except zone 7.
· When bleeding I push hose water through red tap on top right and expel through blue tap bottom right (isolating the incoming and outgoing to mains) About 20% of the water seems to come out and I have no idea where the rest is going. (this may be the problem!)
· When I bleed the other way (hose to blue, expel from red) the full hose force comes out and flow meters move on zones 6-7
· Re pressured the system and left zone 7 actuator off for full flow. (pin in manifold is not sticking)
· Fired up a working zone which calls heat to the flow, working zone gets hot and nothing goes through zone 7, just gets mildly warm.

Other than ripping up my carpets I am lost on what the next things to look at would be. As the flow meters dont move at all when on mains im wondering if this is pressure related. The boiler pressure is a 1.5 bar

Thanks in advance.
Chris – Lancing, West Sussex

 

[Gasmk1]

have you actually undone the feeds for the thermaskirts and checked they are not blocked

 

[surfstar]

have you actually undone the feeds for the thermaskirts and checked they are not blocked

Yes, when bleeding I isolated zones 6-7 and they pass water through flow and return. However pass less water in one direction for some reason

 

[Sharp Point]

There maybe a strong possibility that when you try to purge the loop of air with the cold mains, it’s bypassing through the thermostatic mixing valve.

 

[Sharp Point]

So if so water will take the path of least resistance

 

[Gasmk1]

So if so water will take the path of least resistance

good point thats why i said to take of the flow and return and try that way

 

[surfstar]

Thank you both.
So am i right in understanding that if the purge passes through the mixing valve it is bypassing the loop completely? Therefore the air loop remains in place and the purge test is giving a false positive?
I will attempt to purge direct on to the flow and return removing the manifold and mixing valve completely from the equation

 

[Sharp Point]

Thank you both.
So am i right in understanding that if the purge passes through the mixing valve it is bypassing the loop completely? Therefore the air loop remains in place and the purge test is giving a false positive?
I will attempt to purge direct on to the flow and return removing the manifold and mixing valve completely from the equation

Yes, exactly. Is there any isolation valves either side of the pump?

 

[Sharp Point]

If not you could cut down some plastic the same size as a pump washer and put it in against a pump washer to block the waterway.

 

[Sharp Point]

I will attempt to purge direct on to the flow and return removing the manifold and mixing valve completely from the equation

That won’t work neither, as the ports are mixing

 

[surfstar]

That won’t work neither, as the ports are mixing

I tried this, removed the flow and retrun and pumped hose water down the zone 7 flow and it came out of return as expected. Along with a lot of air and sediment.
Connected back up and problem persists

 

[Sharp Point]

As I said a post or so ago, cut a piece of hard plastic and put it in against a pump washer and tighten the nut back up and then try a hose pipe on the fill/ flush valves.

 

[Sharp Point]

And make sure your flow and return valves are isolated( blue n red)

 

[Sharp Point]

And make sure your flow and return valves are isolated( blue n red)

The 22mm pipes

 

[surfstar]

As I said a post or so ago, cut a piece of hard plastic and put it in against a pump washer and tighten the nut back up and then try a hose pipe on the fill/ flush valves.

Understood. Will give this a go tomorrow and report back