Advice needed - central heating issues

dryjoy

ThisIsWeird said:

Has a magnetic filter been installed? Hopefully this will continue to catch any released sludge.

Yes it has. 

Ibrahim5

We moved into a new house 25 years ago with microbore piping. The builders started us all on British Gas contracts. My dad said "get some inhibitor in that system". I phoned British Gas and asked them to check it but they wouldn't so I told them what to do with their contract. I filled it with Fernox, whilst the neighbours continued with the British Gas contracts. The neighbours started to block up and British Gas charged them £1000s for power flushes. Then they blocked totally. One neighbour in particular who has sadly just died was always asking me if I could sort her cold radiators out. I think once they are totally blocked you probably have to replace the pipework. Mine are all great. Thanks dad.

John_the_Boy

Had a similar problem with my biggest rad that was also furthest away on the heating system. BG came back with a thermal imaging camera to work out where the blockage was. They were just about to replace the blocked pipe when the radiator strangely started to heat up. Never knew why, just assume it was because all of the other rads were turned off and the boiler had been running for ages whilst they were thermal imaging so it eventually cleared the blockage. A bit of extra balancing and the rad now works ok.  

dryjoy

ThisIsWeird said:

dryjoy said:

Yeah one of the non-working ones is a new one, and it’s the new ones that have the microbore pipes. It worked to some extent, but it was never great - at some point in the last few years it’s stopped working at all. 

They’re definitely not BG’s fault, they were an issue before and we just happened to need a new boiler. My one query is over whether they could/should have spent longer on the power flush as they can’t have spent more than 2 - 4 hours on it and some sources lead me to believe it can take a fair while longer if there’s a stubborn blockage somewhere. Might be a long shot though. 

Yes they did try to get these rads working - they said they were unable to, recommended getting a plumber in to really get to the bottom of the issue, but we want to see if there’s anything we can do for ourselves first. We need to let the finances recoup really before lining ourselves up for a potentially big plumbing job. 

This is the UR rad. Not one of the new ones but probably ideal in terms of size and location for some experimentation. This one used to get nice and hot, I’d say it’s only in the last couple of years that’s not been the case. It stays stone cold now. 

That's still quite a heavy rad! But ideal in many ways as the floor is tiled.

Could you, as an initial step, try out what I outlined in my last post, and report back?

I agree - BG will have done what can be reasonably expected of any new boiler installer. They fulfilled their obls.

Clearly you could have asked them to come out and strip down your pipework, looking for the presumed blockage, but that would cost.

It would still be useful to see what the overall layout is, to see if it's obvious where all this microbore pipework began.

So we’ve taken this rad off today. Drained it, took it out into the garden and flushed through with a hose. I have to say the water coming through looked clear, no visible gunk, although not sure whether it would have been noticeable if it was severely blocked? 

With the radiator off, if I open the lock shield valve  briefly we get a moderate trickle of water, on the TRV side the pressure is much higher. Not sure if that is expected but I think the issue is probably blocked pipes as opposed to the rad itself. 

vacheron

dryjoy said:

ThisIsWeird said:

dryjoy said:

Yeah one of the non-working ones is a new one, and it’s the new ones that have the microbore pipes. It worked to some extent, but it was never great - at some point in the last few years it’s stopped working at all. 

They’re definitely not BG’s fault, they were an issue before and we just happened to need a new boiler. My one query is over whether they could/should have spent longer on the power flush as they can’t have spent more than 2 - 4 hours on it and some sources lead me to believe it can take a fair while longer if there’s a stubborn blockage somewhere. Might be a long shot though. 

Yes they did try to get these rads working - they said they were unable to, recommended getting a plumber in to really get to the bottom of the issue, but we want to see if there’s anything we can do for ourselves first. We need to let the finances recoup really before lining ourselves up for a potentially big plumbing job. 

This is the UR rad. Not one of the new ones but probably ideal in terms of size and location for some experimentation. This one used to get nice and hot, I’d say it’s only in the last couple of years that’s not been the case. It stays stone cold now. 

That's still quite a heavy rad! But ideal in many ways as the floor is tiled.

Could you, as an initial step, try out what I outlined in my last post, and report back?

I agree - BG will have done what can be reasonably expected of any new boiler installer. They fulfilled their obls.

Clearly you could have asked them to come out and strip down your pipework, looking for the presumed blockage, but that would cost.

It would still be useful to see what the overall layout is, to see if it's obvious where all this microbore pipework began.

So we’ve taken this rad off today. Drained it, took it out into the garden and flushed through with a hose. I have to say the water coming through looked clear, no visible gunk, although not sure whether it would have been noticeable if it was severely blocked? 

With the radiator off, if I open the lock shield valve  briefly we get a moderate trickle of water, on the TRV side the pressure is much higher. Not sure if that is expected but I think the issue is probably blocked pipes as opposed to the rad itself. 

Oh, you would know!

This is what we we were faced with when we purchased our house in 2010. The silt settles like clay in the lower middle of the radiator, so we were using a hammer drill against a metal plate with a towel as a protective layer in order to vibrate the silt to get it to mix with the water. 

Took about 6 full flushes and 3 buckets of water like this before it began to run clear! 

 

ThisIsWeird

So we’ve taken this rad off today. Drained it, took it out into the garden and flushed through with a hose. I have to say the water coming through looked clear, no visible gunk, although not sure whether it would have been noticeable if it was severely blocked?

With the radiator off, if I open the lock shield valve  briefly we get a moderate trickle of water, on the TRV side the pressure is much higher. Not sure if that is expected but I think the issue is probably blocked pipes as opposed to the rad itself. 

As Vach says, you'd have noticed the inky-black water when you drained the rad  

You drained the rad in situ? So what did the water from that look like?

With that rad - can you see through from one opening to the other - are the two holes in line, with no bends? If so, and you can see the light, then it's clear.

Remind me - your boiler has a pressure gauge? If so, it's a sealed/pressurised system, and will deliver water out an opened valve with a decent force behind it - that's good. But the system pressure will soon drop and will require repeated topping up - that's a wee pain.

Ok, I'd get a larger container under each valve in turn, and figure out a way for the ejected water to get into that container safely. Now, open the valve fully (for TRV, open to 'max', and the l/s open at least a good 4+ turns) and let it spray. Ideally have someone else at the filling-loop, and ask them to maintain a flow to keep the indicated pressure at around 1 bar; it doesn't matter if it drops down, or rises towards 2 bar, just juggle the top-up flow to keep it going, so it keeps on spraying out the valve.

Take a photo of the ejected water flow. Note if it increases or fluctuates much. Note the colour. Check the contents of the container - what do you see?

Now shut that valve - and the filling loop.

Move to the other valve - repeat the process. Open the valve fully. Let it run. Keep the pressure topped up. What do you see?

Do you have a magnetic filter fitted on your system? (Edit - you will, as it's a new boiler).

FreeBear

dryjoy said: With the radiator off, if I open the lock shield valve  briefly we get a moderate trickle of water, on the TRV side the pressure is much higher. Not sure if that is expected but I think the issue is probably blocked pipes as opposed to the rad itself. 

Get yourself a 1/2" BSP hose connector to screw on to the lockshield/TRV body, Run a hosepipe out of the door, then open up the filling loop on the boiler. If there is a blockage in the pipe, water pressure would (hopefully) clear it. You could also try running the heating system with some cleaner added (say Fernox F3 or Sentinal X400) for a few hours before connecting up the hosepipe.

When you refill the system again, don't forget to add corrosion inhibitor.

ThisIsWeird

FreeBear said:

Get yourself a 1/2" BSP hose connector to screw on to the lockshield/TRV body, Run a hosepipe out of the door, then open up the filling loop on the boiler. If there is a blockage in the pipe, water pressure would (hopefully) clear it. You could also try running the heating system with some cleaner added (say Fernox F3 or Sentinal X400) for a few hours before connecting up the hosepipe.

When you refill the system again, don't forget to add corrosion inhibitor.

Good call - that will make it much easier to control.

But do collect the water in a bucket or similar so you can see what's coming out.

Don't panic - you can always shut the valve off any time you need!

With the slower-running lockshield end, make sure it's opened a good few turns, keep it flowing, and keep the pressure topped up - if that side is partially blocked, you'll want to give it a fair chance to clear - and you want to see the results, the evidence.