Central Heating - Radiator Replacement

[CHiLL]

The radiator in my living room has been faulty since I bought the property two years ago. It's warm-hot at the top and cold at the bottom, which is the opposite of the common 'it needs bleeding' issue. I have bled it anyway, just to be sure. I'm suspecting that it has 'sludge', a build up of gunk at the bottom of the radiator.

 

This is the last radiator in the system and the feed pipe to it is scolding hot, however the return pipe is luke warm at best. All other radiators are working perfectly. The common fix for sludge in a radiator is to remove it and blast it out with a power washer or clean/flush the entire system. Both of which appear to be more expensive than just replacing the radiator

 

My question is; Do you think replacing the radiator would fix the issue? I wouldn't be doing this myself, I'd be getting someone in to do it. I don't really want to spend the money, only for it not to fix it.

Edited November 29, 2019 by CHiLL

[mikeprice]

If there is a central heating person or company that you trust then ring them up and ask them

 

They may just look at it and say it needs flushing properly and that will be it

 

or they may look at it and notice that it is mounted wrongly

or maybe the system has more rads that the boiler is designed for

 

or something

 

or they may say it will be better to replace it

 

better to ask an expert really

 

 

in any case - they will know better than I will

[Disease]

I agree with @mikeprice better to get a plumber to look at it and give you his opinion, I changed a radiator myself and it wasn't that much of a chore, couple of youtube vids later

 

Plumber Parts do some great vids.

 

plumberparts

[CHiLL]

Thanks for the replies. Yeah, I plan on getting someone to look at it, it's just finding someone. Unfortunately I don't know of any decent plumbers, so I'll have to ask around at work. I certainly don't think I'll be attempting it myself. I'm pretty useless at DIY and I know that my central heating doesn't have any drain off taps, so it has to be done by disconnecting one of the pipes and draining it into a pan or something. Also the piping is smaller than the standard piping (learnt this the hard way when I had a previous plumber in and things didn't go too well...). I also don't have an outside tap or pressure washer to hose through the radiator!

 

I've contacted a plumber and it looks like it'll cost about £300 to replace the radiator and it would be the other side of Christmas. The guy did suggest getting it flushed instead (which they don't do), so I've requested a quote to another company for having the entire system flushed.

[mrbios]

Could be an airlock, but that could also look the same as a sludge issue.

 

Have you tried turning off all the other radiators in the house by the TRVs just leaving that one on, then turning the heating on for a few minutes then off again? Keep someone by the radiator when you do this as they might hear air move. Is it a pressure based system? EDIT: if it is sludge, i guess probably best NOT to try this incase that pushes the sludge elsewhere through your system.

 

When you say the piping is smaller than usual, is it smaller than 15mm? 15mm is standard internal plumbing for radiators, taps, toilet etc. normalled with 22mm in the main heating ring, and into the house etc.

 

I'm getting quite handy with DIY, bought my house a year ago and have since had to replace two radiators, the 3 port valve and accutator, the pressure valve, also just had my bathroom done and i had to plumb in a new pump for the shower.

Edited November 29, 2019 by mrbios

[elsiegee40]

Cold at the top and hot at the bottom means it needs bleeding.

 

Cold at the bottom and warm at the top is usually sludge. The radiator, or possibly the whole system, needs flushing.

[southhamster]

If it's microbore pipe 10?mm there's a reason it's hardly used any more. Famous for blocking up. Have you tried moving both the rad valves in case they are bunged up?May be very stiff so be careful and possibly may leak slightly when turned.

[CHiLL]

Could be an airlock, but that could also look the same as a sludge issue.

 

Have you tried turning off all the other radiators in the house by the TRVs just leaving that one on, then turning the heating on for a few minutes then off again? Keep someone by the radiator when you do this as they might hear air move. Is it a pressure based system?

 

When you say the piping is smaller than usual, is it smaller than 15mm? 15mm is standard internal plumbing for radiators, taps, toilet etc. normalled with 22mm in the main heating ring, and into the house etc.

 

I'm getting quite handy with DIY, bought my house a year ago and have since had to replace two radiators, the 3 port valve and accutator, the pressure valve, also just had my bathroom done and i had to plumb in a new pump for the shower.

If I recall correctly, the piping is 9mm with 15mm adapters to the radiator valves. The property was built in 1985, so it's not that old. I'll give that a go this evening and see what happens.

 

Cold at the top and hot at the bottom means it needs bleeding.

 

Cold at the bottom and warm at the top is usually sludge. The radiator, or possibly the whole system, needs flushing.

That's what I thought, but I don't want to spend money on something that won't fix it, if I can help it!

 

If it's microbore pipe 10?mm there's a reason it's hardly used any more. Famous for blocking up. Have you tried moving both the rad valves in case they are bunged up?May be very stiff so be careful and possibly may leak slightly when turned.

I haven't tried removing any valves and I don't think I'm confident enough to try because I have no idea what I'm doing. The last thing I want is to remove something and not be able to put it back together.

Edited November 29, 2019 by CHiLL

[Andrew_C]

I know that my central heating doesn't have any drain off taps,

Whatever else you do, get the plumber to fit one as part of the job. Everything in future will be MUCH easier!

[mrbios]

If I recall correctly, the piping is 9mm with 15mm adapters to the radiator valves. The property was built in 1985, so it's not that old. I'll give that a go this evening and see what happens.

 

Oh see my edit, i didn't get there quick enough. As I'm no expect, it might be worth waiting for someone to advise as to whether it's a bad idea to intentionally shift the sludge elsewhere in the system. In theory if it's an airlock it just leaves one radiator for the pump to shift water through, but if it sludge i didn't think about the fact it could just move that sludge "elsewhere" obviously don't want it ending up in the boiler pump or something....maybe someone more experienced could advise on that though.

[CHiLL]

Whatever else you do, get the plumber to fit one as part of the job. Everything in future will be MUCH easier!

Yeah, I will do that. I have no idea why it doesn't have one and it would make sense whilst the system is drained.

Oh see my edit, i didn't get there quick enough. As I'm no expect, it might be worth waiting for someone to advise as to whether it's a bad idea to intentionally shift the sludge elsewhere in the system. In theory if it's an airlock it just leaves one radiator for the pump to shift water through, but if it sludge i didn't think about the fact it could just move that sludge "elsewhere" obviously don't want it ending up in the boiler pump or something....maybe someone more experienced could advise on that though.

Ok, I won't try that then! Last thing I want is for more radiators to stop working correctly, especially when it's getting this cold!

Edited November 29, 2019 by CHiLL

[elsiegee40]

If I recall correctly, the piping is 9mm with 15mm adapters to the radiator valves. The property was built in 1985, so it's not that old. I'll give that a go this evening and see what happens.

 

 

 

Our house was built in 1992. We have microbore downstairs and 15mm visible upstairs!

 

There is no circuit upstairs, microbore runs up the walls at regular intervals from the downstairs circuit to feed the upstairs radiator above.

 

It’s a pain in the backside. We have had sludge problems galore downstairs.

Edited November 29, 2019 by elsiegee40

[Ditto]

This chap has been posted on Edugeek before, but

is a great little video to explain the story with micro-bore.

 

Couple of key points to consider from this video.

1. The blockage could be in the manifold, not the radiator.

2. When he shows you a micro-bore rad value, you'll see it's got a in-built drain-cock. If you have adaptors to standard size, it most likely increases the risk of blockage.

I have used chemical cleaners (Fernox F3 for example) in normal CH systems to good effect, but if you have a complete blockage the chemicals don't get to work so the powerflush is more likely to be needed. I've done a fair bit of plumbing in the past, so draining, cleaning and replacing radiators has saved me a lot over the years and I have avoided the expense of a powerflush, but in the circumstances you describe, I suspect it is going to be the most cost effective solution. Word of mouth is best to get someone, but you would be wise to mention you have a micro-bore system inadvance. Hope you get it sorted soon - it's only going to get colder in the next few weeks!

[Theblacksheep]

I found the https://www.checkatrade.com/ site useful last time I needed a plumber, pick one with loads of good reviews.

[stgoodyeara]

Take the radiator off and take it into the garden and run a hose through it. This will at least give you a free indicator of what the internals are like based on the state of what comes out, you wont be able to flush it fully with a hose as you need some chemicals and some decent pressure that you wont be able to achieve with a garden host to do any damage to years of sludge. Just be aware that powerflushing pushes the pipes and rads to the top end of whats acceptable in terms of pressure. I worked for a city council building maintenance department for a couple of years and i'd say 1 in 10 powerflushes resulted in a leak on the system somewhere.

 

If you do go down the powerflush route....which will inevitably cost you a couple of hundred quid minimum get the heating engineer to fit a filter to the system while they are on. https://www.screwfix.com/c/heating-plumbing/central-heating-filters/cat2840004

 

They aren't cheap, but neither is a powerflush every few years.

[mikeprice]

Last couple of times I have needed a trade person I have used Rated People - done it twice and both were good

 

Checkatrade generally comes up with no-one around here for some reason

 

pity you aren;t near here as I have a tame central heating firm - step-son's father-in law owns it!

[rad]

I’d ask locally on a Fb page.

 

Be aware that places like Rated People, the tradesman have to pay the site to get your details to quote, this works fine when it is a complicated query but not always for other standard jobs.

[rich_tech]

If it's microbore pipe 10?mm there's a reason it's hardly used any more. Famous for blocking up. Have you tried moving both the rad valves in case they are bunged up?May be very stiff so be careful and possibly may leak slightly when turned.

 

I have 10mm ones here and its terrible with those thing pipes, compared to having thicker pipes in our previous homes its noticably worse at keeping the house warm with them.

[Andrew_C]

Got 10mm and no problem with slow warming.