Advice needed - central heating issues

dryjoy

Hi, I’d be grateful for some advice on our central heating if possible. 

We’ve just had a new boiler installed by British Gas (yes we did get other quotes, but they actually came out the best l), however we’ve also long had issues with a number of radiators in the house. 

There’s at least two that are completely stone cold, and two or three others that are luke warm. The other ten or so are working pretty well. 

We’ve bled them many times, and the boiler install people did that as well, so that’s not the problem. 

They also did a power flush as part of the boiler installation but this didn’t improve things. They said there must be some significant blockages somewhere, and noted some of the radiators have small pipes, which they regarded as problematic. They recommended getting a plumber in to look and probably having some radiators replaced. 

However I’m wondering whether they spent long  enough on the power flush. They were here working a total of about 13 hours - it was quite a big install as we had the boiler site moved from the loft to the landing, lots of effort getting the holes in the wall, the new flue in position etc. 

I think they spent somewhere between 2 - 4 hours on the power flush. However having researched a bit, I now have the impression that a good flush could take 8 hours or even more for stubborn blockages (for info, we have 13 radiators). 

So I’m wondering:

• Should we try to get them back for a longer, more thorough attempt at the power flush? We haven’t settled the bill yet, so I wonder whether we could make a case for this? British Gas’ own website says a power flush takes 8 hours or so.  
• Is there anything else we can do ourselves to try and get these radiators working? Having shelled out on the boiler, we don’t have the budget for nice plumbing work in the immediate future.  

EDIT: I should have added, the BG people did try to balance the system as well, and that’s also been done in the past (and we’ve also tried to do it ourselves in the last couple Of years, but with no success, like the BG engineers). 

Lorian

Could be balancing. Could be a lot of things. Are either of the pipes to the ones that are cold warm to touch?

Do all or most of your radiators have TRVs?

.

dryjoy

Thanks - I should have mentioned it’s not balancing either. They tried to balance them, and it’s been done before (and we’ve tried to do it before too). 

A lot have TRVs. Probably the majority. 

FreeBear

I had a dickens of a job balancing my radiators initially. Sat down and had a long think about it and had another go tail end of last year. Turned the pump speed down to its lowest setting, and as if by magic, balancing the radiators became a doddle. On my Viessmann 050, pump speed is set by an option buried in the service menu. A bit of a pain to find it, but at least I don't need to get a Gas Safe engineer out to do it.

Read the boiler installation manual, turn the pump speed down, and give balancing another go.

Lorian

Something quick to try. Make a note of the settings on all the TRVs. Then turn them all to 0 except the ones playing up - set them to 5. Run the heating for 20 mins, do any of the not working ones then start getting warm?

Put the TRVs back then (but they really ought not be set to more than 3)

Also have you checked the TRV pins are not stuck. Don't go pulling the pins out they will leak. you push to test

dryjoy

Lorian said:

Something quick to try. Make a note of the settings on all the TRVs. Then turn them all to 0 except the ones playing up - set them to 5. Run the heating for 20 mins, do any of the not working ones then start getting warm?

Put the TRVs back then (but they really ought not be set to more than 3)

Also have you checked the TRV pins are not stuck. Don't go pulling the pins out they will leak. you push to test

Thanks. We did try turning all but the problematic radiators off a year or so back, but didn’t make any difference. The BG engineers checked the TRV pins, said they were all ok. 

dryjoy

FreeBear said:

I had a dickens of a job balancing my radiators initially. Sat down and had a long think about it and had another go tail end of last year. Turned the pump speed down to its lowest setting, and as if by magic, balancing the radiators became a doddle. On my Viessmann 050, pump speed is set by an option buried in the service menu. A bit of a pain to find it, but at least I don't need to get a Gas Safe engineer out to do it.

Read the boiler installation manual, turn the pump speed down, and give balancing another go.

I haven’t thought about the pump speed. I’ll take a look. Thanks. 

Veteransaver

It's usually stuck pins on the trvs. Obviously make sure they lock shield valve on the other end of the rad is fully open too.
Try shutting off all the rads that aren't working, then run the heating, turn the pump speed up if necessary.
To check the trv pins, remove the trv head and then try pushing down on them with a flat metal bar or something, the pins should move down and spring back up, but not a lot, they are stiff though usually so use some force carefully.
Obviously make sure the radiators don't have air in them either. Does water come out when you bleed them ,ie they have water in them?

Beeblebr0x

Whereabouts are the problem radiators in the run? Are they furthest from the boiler or is it random? 

dryjoy

Veteransaver said:

It's usually stuck pins on the trvs. Obviously make sure they lock shield valve on the other end of the rad is fully open too.
Try shutting off all the rads that aren't working, then run the heating, turn the pump speed up if necessary.
To check the trv pins, remove the trv head and then try pushing down on them with a flat metal bar or something, the pins should move down and spring back up, but not a lot, they are stiff though usually so use some force carefully.
Obviously make sure the radiators don't have air in them either. Does water come out when you bleed them ,ie they have water in them?

Yes there’s no air in them, water comes out, no air when we bleed them. The heating engineers checked the pins, but I suppose it wouldn’t hurt to check them again. 

dryjoy

Beeblebr0x said:

Whereabouts are the problem radiators in the run? Are they furthest from the boiler or is it random? 

It’s a bit random, one of the stone cold ones is one of the further ones, the other two that’s not the case.