Underfloor heating manifold installation - flow direction

24 Mar 2018
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Hi All,

This could open a can of worms... But we have just had 2 manifolds installed for around 120m2 of underfloor heating and the plumber has installed the manifolds like this. Can anyone with technical understanding of these validate if this is installed correctly. I am worried that the lock shields are at the bottom and back. We are having trouble balancing it, and have been told to let it run for a few days before we try.

Problem I have is that the flow meters in the lock shields aren’t even registering flow, the pipes do get hot if set to max but we are also trying to be extra gentle with the screed for the next few weeks as it’s only been in 7 weeks (fast drying 75-100mm cement screed)

Problem I have is I only have a basic understanding of these manifolds, flow direction, calibration and commissioning and so any help would be greatly appreciated.

Picture below. Flow is bottom copper pipe, return is top copper pipe with auto air vent. Flow in manifold is from top actuator bar and return is the red lock shield bar.

Many thanks



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Thanks Russ. I have the technical guys at Ambiente tell me that as well today. Actuators “always” go on the bottom and lock shields on the top.

Thanks for reassuring me I wasn’t going mad.
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D, looking at your setup it is similar to mine I installed 20 years ago, see attached
Actuators, “return” top manifold.
Flow meters “flow” bottom manifold
(It’s a pity the top manifold pipes weren’t routed behind the flow meters)
I have had a couple of issues over the years, one a pump loosing head over a period of time causing flow rates to drop across individual loops and the second was air trapped in the return manifold even though I have bleed valves at the end of both manifolds.
Your new installation I would expect the pump to be efficient but over time I have learnt don’t presume anything (with all the flow valves fully open, do you register flow across all loops? the other observation is possible air lock, how do you bleed the top manifold, I don’t see the air vent on the manifold.
With regards screed, after seven weeks it should be ok but turning the blend valve (temperature) down will
give you protection, do you have floor temp sensors in the heated rooms?


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