Is UFH flow and return reversed?

[Philpee]

Hi Guys,

I wonder if somebody could give me some advice, please?

I've had an extension built, and as part of the project, I had the boiler moved and a single loop underfloor heating fitted to the new extension ground floor.

It seems to me that the UFH flow and return is mixed up.

From the photo, the pipe from the blue valve is much hotter than the one from the red valve. When the heating engineer fitted the boiler, he had the flow and return hooked up incorrectly, and I eventually got the builder to get him back to fix that (hence the hark fittings).

Could someone please advise me if I need to get a Heating Engineer in to fix this, or am I being dumb? I am just assuming that red is flow and blue is return, and the motorised valve is on the flow side.

Thank you for any advice (I don't mind if you say I am being dumb). Unfortunately I have fallen out of love with the builder, so I will have to sort this out myself.

Thanks again.

Phil

 

[Madrab]

Yes, the motorised valve should be on the flow side into the mixing valve on the UFH manifold.

Looking at it though, if the mag filter is correct then that should be on the return just before the boiler and that's what the return from the UFH is connected to.

Turn off the heating and let it cool down. Without turning the UFH on, call for CH. Going by the way it's piped, the left hand pipe running down the right hand side of the boiler should get hot first. Then call for heat from the UFH, the 2 port valve should open, the pump on the UFH manifold should run and the hot water should flow through the 2 port into the UFH manifold via the red handled valve, down through the pump and into the pipe below going into the floor.

If it doesn't then it needs looked at and sorted.

 

[Philpee]

Thanks Rob,

I did as you suggested.

It seems that perhaps the motorised valve is faulty (or not wired correctly), as the return from the blue valve gets much hotter than the flow to the red. The motorised valve does not seem to actuate (the lever remains loose).

The pump comes on straight away, once the UFH calls for heat.

Strangely, though, when the UFH comes on, my Towel Rails come on. The Towel Rail has always come on with the Hot Water (by design) and there is a motorised valve in the airing cupboard to control this.

Could the UFH motorised valve be wired incorrectly, do you think?

Thanks very much for you help. I do appreciate the time that you chaps give voluntarily.

Phil

 

[Lower]

The lever on the motorised valve will be loose if the valve is in the powered (open) position.

 

[Madrab]

I think you need to get them out again and get someone to go through the whole thing from back to front. You don't want the first person back if they somehow got the flow and return back to front. You certainly don't want them back if it still isn't right after they've had an opportunity to sort it and it still isn't right. It isn't rocket science for a qualified installer. The wiring may not be correct either.

As suggested, if the lever on the 2 port is loose it means it's powered up and open so the red valve side of things should be the hotter side if it's all plumbed correctly.