Help with underfloor heating

[Ozz]

Hi All,

Im looking for a little advice from anyone who knows about underfloor heating systems.
I recently bought a house which has underfloor heating downstairs and CH upstairs, all heated from an oil burner. This is my first experience with underfloor heating.

Here is the boiler and Ive marked:
V1: Water filling valve
G1: Water pressure gauge
C1: Controller 1

Here is the UFH manifold:

The heating is working ok. The UFL seems a bit patchy (hot and cold areas) which I assume to be some air in the system. I have been trying to determine exactly how I can flush the system but am finding it hard to get all the info I need. I think this has not been done since it was installed as the previous owner has had the annual service done every year for the boiler but knows nothing about the UFH system. Also the CH upstairs was terrible until I bled the radiators as they were all about half full.

When I bled the CH radiators this also dropped the pressure in the UFH system, then both pressured up together when I opened valve V1 (photo 1) so the 2 systems must be connected (also the hot water is coming from the oil burner).

First I have a few questions:
1- Does it seem reasonable I should flush or bleed the UFH system?
2- Do I need to fill it with antifreeze or can I just flush with water?
3- What is a reasonable pressure to set it at? I increased the pressure to 2 bar on the boiler (max in the manual is 3 bar)
4- What is valve (regulator) V5 for? I cant seem to turn it, without worrying it is going to break... Also Im not sure if it is set to Min or Max (as it is fully turned in one direction).
5- Can you please help with the process for bleeding/flushing the UFH.

I read that I should flush 1 zone at a time. So whats the best way to isolate the zones?
What are the black caps at the top of each zone inlet pipe (they have a valve operated by a key attached at the side). Is this to isolate the zone or to bleed them?
There are 2 hose connection points - 1 under gauge G2 and 1 marked V4. Do I need to isolate all but 1 zone and use a hose connected to V4 and a drain under G2 to flush? Can I just open the valve V1 on the boiler instead of connecting a hose to V4??

As you can see Im not quite sure how to do this so appreciate any clear instructions for help. I can supply further photos if needed.

 

[picasso]

System pressure should be 1 bar when the system is cold

turn the under floor heating on and see if the indicators on top of the actuators move

no antifreeze, water is fine

the valve you cannot move is a thermostatic valve , leave it alone till you get the rest of the ufh working and then you can test to see what temp the ufh is running at

no need to flush till you find out if the rest of the installation is ok.

 

[Agile]

You could try running for about 10 min with each one of the UFH loops turned on individually in turn.

That should force out any air in the loops.

When running it would help you if you had a contact thermometer to measure the flow and return temps on each loop when all are running.

Tony

 

[Dan Robinson]

.... Wrong forum.

 

[Ozz]

Thanks for the replies.

Picasso - The actuators move. The system is working, just doesnt seem quite right, there are often hot and cold patches. Could you explain what the thermostatic valve does?

Agile - How would I do this? Would I just turn down the thermostats in all but 1 room (zone) or should I isolate all but one zone (how?) Where would the air escape to? I thought it was a closed system.

The Real Pin 5 - Which forum should it be in?? I cannot see a more relevant place to post.

Cheers

 

[PullerGas]

You could try running for about 10 min with each one of the UFH loops turned on individually in turn.

That should force out any air in the loops.

When running it would help you if you had a contact thermometer to measure the flow and return temps on each loop when all are running.

Tony

Complete tosh Tony!! There's no way a standard 5-6M head circulation pump will shift air in an UFH loop. Tony, I like you but you're handing out advice based in zero experience or qualifications.

IF there's air in the UFH loops, they need purged by high pressure mains cold water.

Your expansion vessel is grossly under sized also.

 

[dilalio]

Might be Shyte and not air.

 

[Dan Robinson]

The Real Pin 5 - Which forum should it be in?? I cannot see a more relevant place to post

I was referring to my post being in the wrong forum - apologies.

 

[picasso]

Pump on the way out ?

 

[Agile]

There's no way a standard 5-6M head circulation pump will shift air in an UFH loop.

IF there's air in the UFH loops, they need purged by high pressure mains cold water.

I don't expect that the OP would be able to do any more himself than what I have suggested.

If there was a little air in one loop running it on its own might well clear the air.

By measuring the flow and returns as I suggested to him he might be able to get an appreciation of how it is performing.

Depending on what he finds he may well need to call a professional.

 

[PullerGas]

I don't expect that the OP would be able to do any more himself than what I have suggested.

If there was a little air in one loop running it on its own might well clear the air.

By measuring the flow and returns as I suggested to him he might be able to get an appreciation of how it is performing.

Depending on what he finds he may well need to call a professional.

Do you know the first thing about commissioning or balancing an UFH system Tony?
I agree, he needs a Pro in & not some career change chancer or course cowboy either!! The industry has been killed by these rsoles.