Uponor underfloor heating installation

7 Jan 2011
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United Kingdom
Hi All, First time posting on here, so hope this is clear.
As part of our extension we have had underfloor heating installed in the new part of our property. Our builder has installed an Uponor system in a screed floor. The total area of the kitchen and utility room (the areas served by the underfloor heating) is 18 square metres.
It is in a single zone as we don't need to be able to operate the kitchen and utility areas independently of each other.
However...it is our understanding that, no matter which Uponor small area pack is used, a manifold and various control packs should be installed. Initially we were told that these had been on site, delivered as part of the package, but that the workmen had lost the manifold and controls (probably chucked in the skip by accident) and that a new manifold etc would be sourced and installed. Eventually, after a considerable time delay and prompting, the builder sent his plumber to complete the system and then told us that a manifold had been fitted (and demanded the outstanding 25% of the ufh cost). However, we could not see that a manifold had been installed and asked him to clarify, to which he replied that he couldn't comment as he wasn't an underfloor heating designer, and neither could his plumber comment because he wasn't an underfloor heating designer either!
Smelling something fishy, we continued to ask for clarification and even sought technical advice from Uponor (not hugely helpful - they just referred us to their technical specification brochure which shows that a manifold and various control packs are supplied with the system).
At a subsequent meeting, and when pressed on the matter again, the builder explained that a manifold had never been delivered with the system as one wasn't needed. (Why then did he say that a manifold had been installed as, at that point, if it is true that a manifold is not needed then he would have known that).
Also, the wall mounted control for the underfloor heating is a Danfoss one, not an Uponor one (again contrary to what their technical specification says should be used). The builder has told us that Uponor and Danfoss are part of the same company and that Danfoss make all the controls. However we can find no evidence of this.

I would be really grateful if someone who has a little knowledge in this area could explain, in layman's terms (!):
- whether this set up is normal and as per the manufacturer's specification (i.e. no manifold)
- what the implications are of there being no manifold or control, apart from a wall mounted dial (not a thermostat) which just allows us to control whether the underfloor heating is on 1,2,3 or 4! (Reading a little on this site makes me think that the manifold enables water already in the system to be recycled in order to provide good efficiency and energy savings).

Sorry to be so long - thought it best for you to have details. Thanks in advance for any help/suggestions.
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I can't comment about what is normal for a single-circuit however"

1) If there is just one circuit, it could run without manifolds ( note there would be a feed and a return manifold so two. )

2) The manifolds I know include flow-meters, but this is only of real use when balancing multiple circuits. They also incorporate a thermometer which allows you to see flow and return water-temperature which is useful to know to adjust system.

Whether manifold or no manifold, the UFH is a closed-system, so the same water stays in the circuit. If your wall-mounted dial is not a thermostat, then I don't know what it is.

If the manufacturer says a manifold is necessary, it is not really down to the plumber to say it isn;t.

Was a study commissioned with Uponor to design the layout ? Do you have the plans ?

If you paid for the manifolds they should be fitted. In your position I would not pay the balance until done - manifolds are quite expensive components.

Please note that I don't what what the Uponor kit looks like and my comments are based on my knowlege derived from multiple circuit systems.
The ufh is unlikely to be a separate closed system on its own, unless there is a plate heat exchanger for system separation. You need some sort of blending or mixing valve to regulate the ufh flow temperature, which needs to be lower than the flow temperature for the radiators. This valve should have come with the ufh packaged kit.

Please, in your own interests, get this installed correctly, either by educating your installers, or sacking them and finding someone who can do the job.
Thanks to both of you, mointainwalker and mysteryman. Your comments confirm my fears and suspicions.
Not being a plumber I have had to do a lot of reading online and research in order to have enough knowledge to refute the claims made by our builder. We strongly believe a manifold should be fitted. I understand and accept that the system is able to operate without one, but, as you mention, the job of the manifold is blend the water coming from the heat source/boiler, which is around 70-75 decrees C, and way too warm for underfloor heating, with cold water to ensure the appropriate temperature is reached.
We asked the builder whether we are able to isolate the ufh from the rest of the central heating system (for maintenance, repairs, switching off in summer) and he replied that we could use the wall mounted dial (which is not a thermostat and simply has numbers 1-4, like non-thermostatic radiator valves) and that we could turn the whole system off by using the connection valves where it has been plumbed into the hot water system.
I am concerned that operating the system as it has been installed will result in the screed floor it was laid in to crack or be damaged, to say nothing of what this might do to the pipework itself.
Thank you again for your help on this - it is much appreciated.
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Do you have the uponor "Compact Control Pack V4"?

They call it a manifold which is not really correct. All you have is a pump combined with a blender and f&r connections.
Isolating valves should be fitted on the boiler primaries to aid future maintainance.

Can you post an image of what you have?
The comment that Uponor use the term "manifold" for mixing-valve could make sense. If this is the case then it is imperative that it is fitted.

It might help your discussions with the builder to know that under (Building ? ) Regs, the temp of the floor surface must not exceed 30 C as there is otherwise a health risk ( phlebitis , if temp is a lot higher ).

Depending on numerous variables this would usually mean a flow temperature of 40 - maybe 50 C tops , so much lower than a rad circuit.
Thanks again mointainwalker and Norcon. No Uponor Company Control Pack V4 has been fitted. We have previously raised this with the builder, whose response was to send us an out of date (2006) which states that the Uponor small area pack of 14m2 (despite our floor area being 18m2) can "be connected to an existing radiator system operating at typical 82/71C flow and return water temperatures and without the need for a mixing valve, manifold or additional circulating pump". It uses something called an FHV-R valve which limits the surface temperature of the floor. The Danfoss wall control is an FHV-R valve, so I guess the system works. However it does not tally with Uponor's current brochure (to which we have been directed several times) which shows that all small area kits since 2009 (when the brochure was produced) come complete with manifold, compact control pack and wall control.
So it looks like what he has put in was OK a few years ago, but is not what Uponor currently supply.
Also, are Uponor and Danfoss part of the same company? We cannot find any evidence that they are, or that they co-market their products.
Thanks guys - really appreciate your help. Will try and post images tomorrow.
Sorry, it might also be worth mentioning that, when I looked at the Danfoss FHV-R valve specification on their website, it mentioned that this type of valve should not be used in ufh areas exceeding 10m2. Our floor area is 18m2. Even if the builder has cheated and used a 14m2 small area pack, the valve is still insufficient, is it not?
I have the Uponor small zone fitted in my summer house, it is for 15sq/mtr areas and controlled by the danfoss fhv-r mixer control and it works a treat.

I doubt that any one has tried ripping you off, there has just been a lot of misunderstanding flying around.
The plumber probaly wasn't told exactlly what he was installing, ie underfloor. He would have expected brass manifolds pumps etc.
The danfoss control comes in a stupid little box and could quite easily get thrown in rubbish.
You might have a total area of 18sq/mtr but a lot of that will be taken up with fixed items such as units, hopefully that was considered when heating coil was laid. From memory it is the "Meander pattern" that should be used.
i think youve got a return limit valve, they will connect it into the heating pipework nearby.
i think youve got a return limit valve, they will connect it into the heating pipework nearby.

Spot on me thinks

Its not a manifold with pump etc

Its just a thermostatic valve that restricts the flow of water through the coil on the return so that the heatloss through the pipes maintains an average temp on the small area
Not the best idea as you cant turn on earlier than the main heating etc but a simple and cheap way to install U/F systems in small areas

What was specified/quoted for .... U/F is not anything that the average heating engineer should have any probs with

Does the underfloor work and is the room warm

Uponor, in the past, did offer UFH small area packs designed from 14²m upwards.

Today they still offer the SAP of 14²m, incorporating the Danfoss FHV-R valve, for installation guides please click on the link below,


For SAP areas Uponor offer the One-Pack, a self quotation service, for up to 112²m.

These SAPs do contain a manifold, they are called the Compact Control Pack V4s. The manifold will depend on the number of loops that are needed.

For greater than 112²m Uponor offer a bespoke quotation service

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