UFH Manifold Banging

[Tlawrence]

Hi all,

first post here so be gentle!
We have recently installed UFH in around 60M2 of our house. It is a John Guest 3 port manifold assembly with 3 speed John Guest pump & Blending Valve. Each port has an electronic actuator head fitted.
The boiler has recently moved into the loft and is a Worcester 30CDi System boiler controlling a radiator circuit on one valve and an unvented cylinder on another. The UFH system has it's own 22mm feed teed about 1M from the boiler flow / returns.

The system was commissioned after the boiler was installed in the loft (around 3-4 weeks ago). The UFH worked fine for a couple of weeks after that until the plumber returned to fit a magnetic filter to the system. Ever since then we get a loud regular banging noise from the UFH manifold at seemingly random times of the day although typically worse over night (3AM & 6AM seem to be common).

The noise does not go away when switching between the 3 speed settings on the UFH pump although it does change in speed in accordance to the pump speed change.
Turning the blending valve temperature down does cause the noise to go away temporarily although I'm not sure if this is perhaps just due to the temporary reduced flow. I was running the system between 50 & 55 degrees C. When I reduce it to around 45 then the noise stops. I still get the odd squeak periodically like a bubble of air is squeezing its way through the pump but not nearly as severe as when at 55.

I had initially assumed that installing the mag filter had introduced some air into the system (well, it definitely did as I had to bleed all the radiators).
However, every time I the banging has occurred (even at 3AM :-( ) I have opened the bleed valve on the pump and even tried cracking off unions to let air out. This doesn't seem to have made a difference.
The only thing I have not done is a full bleed of the UFH loops using the filling valves and opening one loop at a time. Do you think this may help? It doesn't sound like air in the loops as I'd expect this to be a more regular noise as the air cycles through the system.

Video of the noise:

Hope you can help. It's driving us mad and result is turning UFH off in the night which means ruddy cold house at the moment!

Tim

 

[Riley]

Could well be air but why are you not getting the installer back?

 

[Tlawrence]

I’m happy to get him back. It’s kind of a joint effort though. I installed the UFH. He just moved the boiler and tank into the loft. Not sure he’s a UFH expert hence asking the wider audience here

 

[ShaunCorbs]

air or pump maybe

pop the zone heads off just incase its one of them

 

[Tlawrence]

It happens with all actuator heads off and also with flow meters closed one at a time so dont think that’s it

 

[Sharp Point]

Try swapping the pump

 

[chris watkins]

Tim that noise is a non-return valve snapping shut & you can see the shock wave moving the flow meters in the manifold.
Check the blending valve.

 

[Tlawrence]

Thanks Chris,

What do you mean check it?is it serviceable in some way? Having turned it right down to 45 last night the situation seems greatly improved

 

[chris watkins]

They are often fitted with spring loaded check valves in both inlets.

 

[island fling]

I have seen this issue & it was the flow & return round the wrong way into the blending valve so maybe worth a check.
What flow rates are you getting on each loop? Is there an auto by-pass valve fitted?
Does it make a difference if the radiators are being called / not being called at the time. So if the issue happens & you call for heating upstairs does the issue ‘go away?’

 

[Nicholas Tims]

Any update on this? I've got newly installed UFH whose manifold is banging in a similar manner.

 

[mrT123]

Old thread I know! Been dealing with the same problem for last two years! Tenants unfortunately landlord doesn’t want to pay the real price to solve the real problem!
Had mixer valve and pump changed and temporarily resolved the problem. It’s back again same problem.

They were advised two years ago to have a flush through UFH by another company who serviced the external air source pump. They never did it, they also had a quote from my friends company who are heating engineers, advised to change the manifold along with the actuators pump and mixer valve and full power flush through the UFH systems pipe work.
Might have even got away with a power flush two years ago!
However since the problem has arisen again another local company who specialise and work along side the company who serviced the air source pump have advised the very same thing as before with the manifold etc to be all replaced and flushed.
Guess who didn’t get there rent this month! Sick to the back teeth of the system waking me up at 3:30 to keep the place warm.

 

[mr1234]

Old thread I know! Been dealing with the same problem for last two years! Tenants unfortunately landlord doesn’t want to pay the real price to solve the real problem!
Had mixer valve and pump changed and temporarily resolved the problem. It’s back again same problem.

They were advised two years ago to have a flush through UFH by another company who serviced the external air source pump. They never did it, they also had a quote from my friends company who are heating engineers, advised to change the manifold along with the actuators pump and mixer valve and full power flush through the UFH systems pipe work.
Might have even got away with a power flush two years ago!
However since the problem has arisen again another local company who specialise and work along side the company who serviced the air source pump have advised the very same thing as before with the manifold etc to be all replaced and flushed.
Guess who didn’t get there rent this month! Sick to the back teeth of the system waking me up at 3:30 to keep the place warm.

hi did you ever resolve this issue, if so what was the remedy thanks