Underfloor Heating - Flow meter issue

[Rushi P]

Hi All,

I was wondering if someone could help me, I've been struggling so much with one outstanding issue in regards to my underfloor heating. All of the zoned Flow meters/gauges don't seem to be indicting an increasing in flow, I have attached a picture to show you...

I have recently taken the flow meters out to clean the dirt inside, just in case something is clogging it up but this has caused what looks to be a little air in the tube... The red indicator continues to stay up.

The actuators are opening the valve, the flow seem to get hot, but the return pipes do not, I've had the heating on solid for 2 days.

All seems okay with the system apart from this annoying issue! Do you think I need to replace them?

Thermostat calling for hot water
45" heat going through pump.
Pump switching on and off
Actuators open valve

I even purchased some Salus Auto Balancing actuators thinking that this will resolve the issue because they have senors on the flow and return pipes to balance the temperature.

In fact I have to say I got a 15 minute spurt whereby the return pipes got piping hot, I though it was all resolved but it didn't last.

I'm sure this all boils down to not having enough flow in pipe system as indicated by the flow meters.

Any suggestions on what I can do?
Any assistance would be much appropriated, this is really giving me a headache just thinking about it constantly for the past few days!

Thanks in advance

 

[Fly1000]

Having a few issues myself, but have learnt alot. No expert but happy to help.

Does the pump run after the 15mins ?
What is the Mix temp set too ?
What are the Thermostats doing are they still calling ?
What is the flow and return Temp difference ? 7c is ideal on the pipes.


How are the Salus ? Thinking of buying a set to help my issues out.

Fly

 

[Rushi P]

Hi Fly,

The pump is newly fitted because I thought that was the issue, seems to be running fine.
I have set the mix temperature to 50, it was 45 before.
The thermostat is constantly calling for heat, I see the boiler temp plus the flow pipe from the boiler is very hot.
The flow temperature is hot, the return pipes are not warming up at all, in fact I havent got a temp gauge but Im sure there is not a 7c difference.

In regards to the Salus, they havent really worked for me, so not impressed although the issue I have could mean the Salus auto temp actuator would never have worked.

Thanks
Rushi

 

[Fly1000]

Have you tried winding the flow meters out to allow max flow on one loop and closing the rest. Could be air stuck in and you need to force it out. do this on all 4 zones ( so 1 open other 3 closed ) also my mixing valve was set on the splines wrong. So I set it to 45c and that was actually 25c flow. As long as the pump is pumping the water should be going somewhere.
You will need to take the Powered actuators off for the above procedure of course.

 

[Rushi P]

Thanks Fly, so you make a great point to which I have done but not mentioned esrlier. I closed all flow meters and left one open. It worked! Hence why I purchased the Salus auto balance actuators.
Do you think I should repeat the process for each zone?

 

[Fly1000]

Yes, if all run ok, then you may need to up the pump speed a little. How long are the loops do you know ?

 

[Rushi P]

So I had a plumber round yesterday, just because I’ve spend way too much time trying to figure this issue out.
He feels that although I’ve tried to flush the system out using a home hose, this would not generate enough force to clear out the dirty that may have been caused. He feels the radiators upstairs have particles that have resided into the under floor pipes over time, so it needs a proper pressurised push.
I’m willing to give this a go because this could be the only issue I guess, he’s coming back tomorrow to carry out the work.
Although my heating systems are on two thermostats 1)radiator/hot water 2)underfloor heating, the pipe system is the same hence the build up. The flow meters did have some rusty slums built up before I cleaned them so I guess it’s possible.
The alternative for future issues is to get a separate boiler but then again that will be a costly fix.
I’ll see how the power flush goes and take it from there. Maybe I’ll just have to flush the system out every couple of years, I could potentially learn how that’s done, not sure.
Will let you know how that goes.
Thanks Fly for all your messages.

 

[Madrab]

Do you have a mag filter connected to the system?

You shouldn't really have to flush the system every couple of years. As long as the system is flushed and filled properly to start with and then set up correctly there really should be an issue with debris.

A mains flush, mains water pressure and flow dependent, can supply a significant force to clean the system out, that coupled with a system cleaner that's been run in the system for a few days.

Make sure, that as your plumber is stating that debris is the issue, that the powerflush he has recommended (and performing?) actually corrects the issue and that he'll guarantee it.

 

[Rushi P]

Thanks, we discussed the mag filter because I did mention that this should pick it up but the plumber said it has been fitted on the return. so I guess it means the particles go through the under floor heating.
I’ll check this with the plumber before he starts tomorrow, thanks

 

[Madrab]

Nope, the idea of the filter being placed on the return, as close to the boiler as possible, is to stop the particles getting to the boiler. If it's working properly then it should be catching most of the debris before it gets to the boiler, then the flow and then to the UFH.

How old is the UFH? How black was the system water prior to the clean?

What make is the mag filter?

Not not sure I would be at the powerflush point quite yet. I would be trying to set the system up properly first before getting there.

 

[Rushi P]

I got the house done back in 2017, didn’t even use the UFH much last winter. Makes sense about the mag filter being close to boiler, the make is a MagnaClean (well that’s all I see on it) have added a picture.

The flow meters did have a rusty look about them before I cleaned them out. I’m also a bit surprised about it needing a flush so soon, but the guy did say everything else looks fine.

Thermostat calling for heat, boiler sending hot water, pump turns on, hot water pipe before pump gets hot, flow on manifold is hot, it’s just the return pipe never gets enough of the hot water. Added another few pics.
Thanks

 

[Rushi P]

So Fly and Madrad, thought I’d provide up update and take the opportunity to say thank you for all the input.
The plumber has been and gone and the issue looks to be sorted.
He started a power flush and realised that when rotating the flow the opposite way there was an issue.
I've put a picture up but basically that area on the return was simply clogged up, look to be particles that were crystallized to the point whereby it was affecting the return side. Luckily the is a filter type ring that captures the dirt.
It's all been cleaned up and I guess I know what to look for if it's a continuing issue with my ufh in a year or so.
Not sure there is anything I can do to rectify now without spending a fair bit.
It's also had the power flush so I'm hoping this will last now.
He also fixed a wiring issue so that I don't need to turn on water (pump) and the heat separately which was annoying.
Anyway he was here for about 4 hours and was open to explaining things because I had a good understanding of the system.

Thanks all.

 

[Fly1000]

Add some extra inhibitor and a Magna Clean and Im sure you will be good.

 

[snb]

Looks like you have automatic flow balancing actuators. You need to make sure you have the correct sensor attached from each actuator on the flow and return pipe work from the underfloor. You also need the flow controls to be set fully open. The actuators are designed to adjust continuously to achieve a differential of 7 degrees