Immokk

UFH not working for nearly a year

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@immokk in an earlier post you mentioned a cold section of floor. How large is this room? And am I correct in thinking in this room with the cold and warm sections, the warm section is larger than what could be expected from a UFH single warm feed pipe enroute to another room?

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1 hour ago, epsilonGreedy said:

@immokk in an earlier post you mentioned a cold section of floor. How large is this room? And am I correct in thinking in this room with the cold and warm sections, the warm section is larger than what could be expected from a UFH single warm feed pipe enroute to another room?

Hi there @epsilonGreedy yes, the warmth when its working quite well (but not properly) gets fairly close to he middle but over time that gets progressively worse and ends up being only the very edges but, specifically in the kitchen (as its tile and easier to tell).

 

I'm fairly convinced it is air somehow as each time it's drained out and refilled through each loop, it works for 24 ish hours afterwards very well then progressively works less well over the course of a few days to a week until the floors are almost entirely cold.

 

No-one seems to know why and I wonder if the previous suggestion of an auto air vent might help?

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2 minutes ago, Immokk said:

each time it's drained out and refilled through each loop

 

When you say drained out and refilled - is that really the case. UFH can't really be drained as a radiator system can be because you can't get low enough in the circuit.

 

When I installed our solar thermal I had a helluva job getting the air out of the system - in this case because the top of the system was on the roof and there was no way to bleed it at the top.  I ended up connecting the system to the mains and running mains pressure water through and out which successfully took all the air out. It was a fiddle to get the antifreeze back in but it worked.

 

So the question is, when you say drained out and refilled, are you sure that any air pockets are actually driven through the system and out before it's recommissioned.

 

Simon 

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Thank you for your answer

 

He hooked a hose up to my outside tap and ran it out into the drain outside. So I assume he "drained" it in the respect that you describe above.

 

It's odd that it works for a period and then the flow drops back down to 1 from 1.5-2 over 12- 24 hours.

 

That flow is just enough to get warm floor in the tiny hall but other rooms are just too big for that it seems.

 

Even the hallway floor will eventually stop warming.

 

There is potentially still air but I don't know how he fixed that if he's spent the time doing what he's done. 

 

Perhaps the suggestion of doing that again and letting it run for a long time then installing an auto valve.

 

I don't know enough to know if that will work or, indeed, can work on my system.

 

It's pretty exhausting to still be having these conversations with the engineer after 3 months...

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5 hours ago, Bramco said:

When you say drained out and refilled - is that really the case. UFH can't really be drained as a radiator system can be because you can't get low enough in the circuit.

 

3 hours ago, Immokk said:

He hooked a hose up to my outside tap and ran it out into the drain outside. So I assume he "drained" it in the respect that you describe above.

This is referred to as 'purging' ;) Basically you take cold mains and blast it through the UFH loops to rid the system of pockets of air that cause air locks ( which significantly reduce or even stop the water from flowing through the loops ). The reason to need to purge is that the UFH setup is designed to flow at very low lpm flow rate, so basically any trapped pockets of air, or indeed an established air lock, would never get shifted as the flow potential of a commissioned system is insufficient to push said air out by itself. I've lost track of how many clients I've been called out to with such issues, and just purging the loops all out has resolved the issue.

The purging needs to be done quite religiously and when disconnecting the temporary hook-ups to perform this, you then need to make sure that no air then gets back into the system and cause the same problem again immediately after setting it all back to work!

One issue, the whole arrangement seems to be upside down. If you look at every pump manufacturers literature, it shows the recommended / correct pump orientations, not one I've seen ever shows the pump pumping down :/ . Reason being, is that air bubbles tend to get caught in an infinite loop of being sucked into the pump, the pump being insufficient to push them away, and then the bubbles want to return upwards and back through the pump when it stands still, and around that cycle keeps going. The UFH rails should be; flow at the top, and return on the bottom.

@SteamyTea makes the same observation as I, as in you should really have automatic air release valves ( bottle vents ) on each rail, or at least the higher one, to release any air pushed out of the loops / otherwise accrued in the manifold rails. Get them fitted and ( ideally ) get a plumber to swap this lot the right way up  

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Ok. So I googled older PP UFH setups and they do actually fit the pump upside down and put the rails the ( IMO ) wrong way around!?! They change this in their latest / current offerings to the 'right way around'...... 🤔

Has the system been re-treated with inhibitor after / during each plumbers visits? 

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Just found this thread.

 

I had an issue 2 years ago on one of my manifolds. Some rooms weren't getting warm and it wasn't obvious why.

 

There was a problem with the mixer valve where water only flowed properly when it was set to a very specific temperature. As you turned the mixer valve up and down the pipes would make hissing and gurgling noises and the flow would start again. Then it might stop randomly.

 

Then installers said it was very unusual for a mixer valve to fail, but just replaced it and it has been fine since then.

 

The fact you said that the flow varies may mean it is something similar. It may of course be something else entirely.

 

It is easy to check, when the heating is calling for heat and the pump is running, turn the mixer valve up and down and see if the flow changes depending on the setting on the valve. My flow gauges would bounce up and down when I did this on the broken mixer.

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10 hours ago, Nickfromwales said:

This is referred to as 'purging' ;)

 

I knew there had to be a technical term for it!!  😄

 

Interesting point about things being upside down and the pump just forcing any bubbles back down - off to check how the one in our current house is plumbed in!!

 

Simon

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10 hours ago, AliG said:

Just found this thread.

 

I had an issue 2 years ago on one of my manifolds. Some rooms weren't getting warm and it wasn't obvious why.

 

There was a problem with the mixer valve where water only flowed properly when it was set to a very specific temperature. As you turned the mixer valve up and down the pipes would make hissing and gurgling noises and the flow would start again. Then it might stop randomly.

 

Then installers said it was very unusual for a mixer valve to fail, but just replaced it and it has been fine since then.

 

The fact you said that the flow varies may mean it is something similar. It may of course be something else entirely.

 

It is easy to check, when the heating is calling for heat and the pump is running, turn the mixer valve up and down and see if the flow changes depending on the setting on the valve. My flow gauges would bounce up and down when I did this on the broken mixer.

 

Yes it does! Immediately on changing the the temperature there is a noises, the flow gauges bob up and down then go back to just the one.

 

I've been telling them that I've only been having the problem since the valve was replaced and the flow has been a problem since. It does improve immediately after getting air out but not for long.

 

I've asked for the mixing valve to be checked and all they say to me is that the valves are basically never faulty.

 

@Nickfromwales thank you for the advice and the tech term...  the system is pretty old and I can't really afford to pay for someone to change it right now, especially with how much this ahs been costing me. You ask this: "Has the system been re-treated with inhibitor after / during each plumbers visits?" and my honest answer, is that I'm not sure. where exactly should the automatic air vents be placed so I can be very clear to my engineer.. then I can have him do both at the same time? I read yesterday they should be after the pump but there is obviously no space for that. You say on both bars... would it be at the ends?

 

Thank you so much everyone. I think I need to insist on the valve being changed and ask for the air vents to be put in.

 

I will keep everyone updated and lets hope it works. I can't tell you all how grateful I am. It's been... not fun.

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17 hours ago, Immokk said:

Hi there @epsilonGreedy yes, the warmth when its working quite well (but not properly) gets fairly close to he middle but over time that gets progressively worse and ends up being only the very edges but, specifically in the kitchen (as its tile and easier to tell).

 

 

I wonder if that warm edge is a consequence of a separate UFH pipe loop that routes to another room where the UFH is working. It would be good to know the dimensions of the room with the hot and cold floor sections then folks here can estimate how many heating loops are under that room.

 

Your UFH pipes are numbered, do you have a plan showing which rooms they service? 

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3 hours ago, Immokk said:

Yes it does! Immediately on changing the the temperature there is a noises, the flow gauges bob up and down then go back to just the one.

 

3 hours ago, Immokk said:

I've asked for the mixing valve to be checked and all they say to me is that the valves are basically never faulty.

 

This does sound similar to what I had and changing the mixer valve fixed it. They didn't see how it could be the mixer valve which was only a year old and checked pressure etc but eventually they just replaced the valve.

 

Some days the water would flow correctly or at some settings on the mixer valve or simply by changing the setting on the mixer valve then it would stop flowing again a little later.

 

3 hours ago, Immokk said:

Yes it does! Immediately on changing the the temperature there is a noises, the flow gauges bob up and down then go back to just the one.

This is exactly how mine acted, changing the temperature on the mixer valve should have no impact on the flow and make no noise unless some issue with the valve is stopping the water flowing correctly. By turning the pump up to maximum you could force some water through the loops and get a little heat. I have 4 manifolds and all the other flow at 3lmin immediately on opening.

 

Changing the mixer valve is a quick and relatively cheap job. As well to do this as pay for hours messing around.

 

3 hours ago, Immokk said:

where exactly should the automatic air vents be placed so I can be very clear to my engineer.. then I can have him do both at the same time? I read yesterday they should be after the pump but there is obviously no space for that. You say on both bars... would it be at the ends?

 

They go on the last spare port at the end of the manifold usually. You don't have a spare but I think they can fit one on the end.

Edited by AliG

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Just a quick update... he's on his way to fit a new valve. I am hoping he is also fitting the automatic vents as asked but I was a bit concerned he didn't sound too sure about them and aso, as you say @AliG , there are no spare ports so hoping he knows where they should go!

 

I'll update tomorrow but hopefully that update will be that it is all sorted!

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On 03/03/2021 at 11:20, Immokk said:

Just a quick update... he's on his way to fit a new valve. I am hoping he is also fitting the automatic vents as asked but I was a bit concerned he didn't sound too sure about them and aso, as you say @AliG , there are no spare ports so hoping he knows where they should go!

 

I'll update tomorrow but hopefully that update will be that it is all sorted!

 

So... when we took the Mixing valve off the manifold it was full of a reddy/ brown/ clay coloured sludge. We have no idea what it is or why it was in there and why it impacted the system to quickly after installation. The mesh inside the mixer was completely clogged up.

 

The heating has been working since yesterday, the flow gauges are open well and they haven't closed off again (yet). I'm not convinced the centre of the floors are quite as warm as they should be but he think that's balancing so now we need to figure out which room is which on the manifold.

 

 

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2 minutes ago, Immokk said:

So... when we took the Mixing valve off the manifold it was full of a reddy/ brown/ clay coloured sludge.

 

Do you have a magnetic filter like a Magnaclean on the system and do you/have you inspected it? 

 

Do you have inhibitors (in the water).

 

 

 

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10 hours ago, Onoff said:

 

Do you have a magnetic filter like a Magnaclean on the system and do you/have you inspected it? 

 

Do you have inhibitors (in the water).

 

 

 

Thank you for the reply.

 

I don't know is the answer to 1 and as far as I'm aware he did not out inhibitor in.

 

It's frustrating as i feel like everyone us doing a half a*** job on it! But I have heating right now... for how long, who knows.

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8 hours ago, Immokk said:

Thank you for the reply.

 

I don't know is the answer to 1 and as far as I'm aware he did not out inhibitor in.

 

It's frustrating as i feel like everyone us doing a half a*** job on it! But I have heating right now... for how long, who knows.

I think it would be wise to get this power-flushed once and for all. That should sort this out long-term and leave you with a healthy refreshed installation. At that time, if it turns out you do not have a magnetic filter ( Link to a robust example here ), you might want to get one installed, and also instruct that person to treat the system with inhibitor ( and watch them do it ). Once this is done, you should have trouble-free motoring from that point onwards. 

Is your home UFH only, or do you have radiators there too? Trying to work out where this corrosion ( and subsequent build up of goop ) is coming from?

Have you had the automatic vents fitted? Pics?

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With help from the good folk on here I've just power flushed my system. Beforehand you add a cleaner that loosens everything up. When I then flushed the level of muck that came out was impressive. I've also now added inhibitor and a magnetic filter which you can perioidically inspect (without draining down) as the iron based crud sticks to it. End result is a more efficient, quieter system. Parts of my system are 50+ years old and have never been properly flushed or had any inhibitor in.

 

Lots of horrible goop like this in there:

 

20181212_195250

 

2018-12-12_06-57-51

 

I was lucky that I could borrow a flushing rig as this video shows:

 

 

This then is even AFTER adding the magnetic filter. You can simply, periodically, remove this bit and wash the collected crud off. (After 50 years etc there's a lot of crud in there). Also my downstairs rads are an antiquated, "single pipe" system which are awkward to flush:

 

IMG_20201113_210216961.jpg

 

IMG_20201113_210237287.jpg

 

IMG_20201113_210553812.jpg

Edited by Onoff

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Thank you so much @Onoff and @Nickfromwales

 

That picture the top is the exact colour that was splattered around the inside of the mixing valve.

 

I'm getting increasingly frustrated with my engineer (although I think he's a good guy):

 

  • I asked him to install automatic air vents, he came on Wednesday with a new valve and no vents. Insisting it wasn't necessary. So @Nickfromwales no, I still have no vents. I'm so tired of fighting with them over this stuff. Apparently, despite all of the screwing around they've been doing they still know better. I am partially suspicious that he is not sure how to do it on my system and this is why he hasn't.
  • I asked him to bring and use inhibitor. He said he would and on Thursday returned and, decided as the system was now working (at least for the time being) and there was nowhere to add it, he didn't feel like purging the system again in order to add the inhibitor was a good idea.
  • He was convinced the muck was not corrosion etc and that it came from the old pump/ new pump when it was changed. He said it was the wrong colour (expecting black)

 

Do you guys know how much a power flush should set me back? I'm exhausted with all of this and feel that I shouldn't have to press so hard to get the things I ask for done and yet, here I am, still faffing around. I'm totally okay to pay for it but don't want to be ripped off and it would be good to know what ball park I should expect.

 

Thanks again for continuing to take the time to try to help me.

 

EDIT: I only have UFH, no radiators.

Edited by Immokk

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1 hour ago, Immokk said:

although I think he's a good guy

 

Whoever installed the system and didn't put in a mag filter or certainly inhibitor then they are not good guys! 2004, the original install? Boiler replaced in 2018, I'd have expected a flush and the suggestion of fitting a filter then. I'm no expert (as many on here will attest to btw). To me yours is a "modern" system. Having no inhibitor and a dirty system just increases your fuel bills and raises the chance of an issue / pricey call out. 

 

The time to add the filter is when it's drained down. Thereafter it is a doddle to periodically remove the filter and wash away debris the magnet has collected and again a doddle to add inhibitor via the dosing pot.

 

This is atypical of a mag filter on the return leg to the boiler.

 

IMG_20201029_192048787

 

At it's simplest:

 

With the boiler pump off, the black valve either side isolates it.

Once you've done that you let the air out on top via a bleed screw (screwdriver).

You then unscrew the long magnet that goes down inside the pot. All the crud that was held in the pot by the magnet now floats loose inside the pot.

Hold a jug underneath and unscrew the plug underneath (Allen key).

The cruddy water falls into the jug.

 

You can unscrew the lid completely to withdraw a gauze screen that catches any big lumps. At the same time you can add inhibitor.....don't forget to put the plug back in underneath.

 

Once done you open the isolation valves and any air comes out the bleed screw. When you see water tighten it up.

 

Takes less time to do this than it did type! 

 

Before a flush you want a cleaner running round in there for a bit to loosen everything up.

 

NB: The black crap that comes out will stain anything! Hands, white sinks etc. 

Edited by Onoff
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38 minutes ago, Onoff said:

Whoever installed the system and didn't put in a mag filter or certainly inhibitor then they are not good guys!


+1.

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On 23/02/2021 at 10:30, Immokk said:

https://www.dropbox.com/sh/qjb6brq1rbspjrb/AAAOjN83eTm4QGc2u3giiD-ra?dl=0

 

Thank you so much for taking the time. 

 

Here are more pictures (in drop box). And one below showing temps. Hope this works! 

 

The pipes when I felt were warm to touch but I could easily hold them and none were hot. 

 

The two temp gauges are similar temperatures for flow and return (the flow gets up to just below 40 although if you look at the mixing valve on one of the pictures, I feel like that's open to full, which I think is 60c)

 

Added info: the pump light comes on, when the demand is sent from the wall thermostat to the boiler, and the boiler kicks in, the flow gauges drop from the top (open)

20210223_085248.jpg

 

 

I've been back over the OP and some of the follow up posts.

 

Its clear there is some sort of flow issue but it could be in one of two places:

 

1) Around the floor loops: I think this has been disproven by the fact that the red loop flow rate indicators show adequate flow.

2) Between Boiler and manifold through the mixer.  

 

In the OP you said..

 



We did notice that the downstairs demand goes to the boiler and the boiler fires up but then after not long the flame icon on the digital panel goes off. After a while it comes back on again. Then off. Then on. This doesn't seem to happen with the upstairs manifold.

 

That sounds like the boiler is shutting itself off because the flow temperature is getting too high.  If you can catch it doing this check the temperature of the flow and return pipes near the down stairs manifold. There can be two causes..

 

a) There is flow but its all bypassing the manifold due to an issue with the mixer. This could be proved/disproved by the temperature of the boiler flow/return pipe near the manifold. eg If both are boiling hot the issue is with the mixer (Which I note you had replaced shortly before the problem started).

 

b) There is no flow. In this case the boiler flow and return near the manifold would be cooler. This could be due to an issue the pump that circulates water from the boiler to the  manifolds or the signals that control it. If the pump wasn't working then you might still get flow to the upstairs manifold due to thermosyphon (aka heat rises). Check if this pump runs when the downstairs manifold calls for heat.

 

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