Central heating clogging up

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Simpo Two

Original Poster:

85,321 posts

265 months

Saturday 21st January 2017
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My boiler (1988 Ideal Elan) has increasingly been struggling/wheezing/cutting out every minute, and occasionally the pipes make a loud clonk. I thought it was scale in the heat exchanger. A few times I've had plumbers in to declag it with Fernox etc, and it's improved for a short while then got worse again.

Yesterday a kindly plumber popped in at short notice and in order to get the hooch into the boiler as directly as possible, drained the system down a bit, then cut into the overflow pipe in the roof and poured the stuff straight down. We were surprised to see that the overflow pipe was half clogged with black gunk and bits that he called Magnetite. If the overflow pipe is that bad it doesn't say much for the rest of the system...!

He recommended a magnetic filter be fitted above the boiler in the return pipe, and then he goes round 'vibrating' each radiator to shake loose the clag and get it to stick to the filter. This way he gets as much out as they can and estimated about £500. He felt that a pressure wash would put too much strain on the system.

The house is 28 years old, standard gravity fed system, and I can't think of any other way to solve the problem. Replacing the boiler would give me a new heat exchanger but wouldn't affect the rest of the system.

If anyone can suggest other ideas I'd be pleased to hear them smile

FurtiveFreddy

8,577 posts

237 months

Saturday 21st January 2017
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£500 sounds a bit high to me for what you're saying he'll do and it won't even guarantee the issue will be resolved.

I'd get a CH engineer in for a second opinion.

Simpo Two

Original Poster:

85,321 posts

265 months

Saturday 21st January 2017
quotequote all
FurtiveFreddy said:
I'd get a CH engineer in for a second opinion.
Hmm, well his card says 'plumbing and heating' and he's Gas Safe - does a CH engineer have extra qualifications?

FurtiveFreddy

8,577 posts

237 months

Saturday 21st January 2017
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Simpo Two said:
Hmm, well his card says 'plumbing and heating' and he's Gas Safe - does a CH engineer have extra qualifications?
I've dealt with a few plumbers and heating engineers over the last couple of years during the refurb of two family houses, a new kitchen in my house and two central heating upgrades and IMO I'd say there is a difference between a general plumber and someone who only installs and maintains boilers and CH.

The qualifications and expertise required to become a gas safe engineer these days doesn't guarantee much, as was proved to me when the one contracted to sort out my kitchen managed to violate and ignore building and safety regs causing problems which took the best part of a year to sort out.

I'm certainly not trying to make out that all plumbers know nothing about heating, but there's a lot to learn and keep up with when it comes to doing a proper job of installing and optimising a central heating system and I realised that once I (eventually) found a specialist who really took an interest in his job.

Of the 7 plumbing and heating companies I've dealt with (and paid money to) during these last couple of years, there's only 1 I would use to do anything CH related.

So my advice is to look for a central heating specialist who does commercial and domestic work as they'll have more experience.

moles

1,794 posts

244 months

Saturday 21st January 2017
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A magnetic filter will help but you will always be polishing a turd as it were if the 22mm open vent is half blocked. If this pipe is blocking up the rest of the system will be 10 times worse. A flush will get rid of most of the dirt but not all of it and you may well get leaks on radiators if it's that old and dirty (sometimes the magnetite holds the water in the rad if they are that rusted). Systems that are that dirty are usually caused by the builders not flushing them from day one and they are normally piped up incorrectly in the airing cupboard so they draw air in.

Rickyy

6,618 posts

219 months

Saturday 21st January 2017
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Personally, I would fit a magnetic filter to the boiler return, run a decent system cleaner through the system for a week or two.

Then drain the system, take the rads into the garden and flush them through with a hose pipe.

Get someone in which is experienced in open vent heating systems. The cold feed, vent and pump configuration is crucial. If it's wrong, it can cause pumping over which can promote corrosion.

Wings

5,813 posts

215 months

Saturday 21st January 2017
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Rental flat with combi boiler and magnaclean already installed, over past 12 months regular boiler breakdowns, with a couple of the radiators having cold spots. Just had the system power flushed at a cost of £450, no breakdown faults presently reported, although the above couple of radiators still have their cold spots, and will therefore need replacing.

I would recommend a second, third opinion, and not just a plumber, boiler engineer, but one who specialises on carry out power flushes.

guindilias

5,245 posts

120 months

Sunday 22nd January 2017
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Simpo Two said:
The house is 28 years old, standard gravity fed system, and I can't think of any other way to solve the problem. Replacing the boiler would give me a new heat exchanger but wouldn't affect the rest of the system.

If anyone can suggest other ideas I'd be pleased to hear them smile
Gravity fed? Throw a pump on there and you'll get a lot less sludge - and faster heating up times. Then stick in a litre of X800 once you have your filter in, then dump the lot and add a litre of X100 when you refill.



guindilias

5,245 posts

120 months

Sunday 22nd January 2017
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Oh, and "vibrating the system" to free up sludge normally means hitting the rads with either a hammer wrapped in a towel, or a rubber hammer so as not to chip paint off. It's not hard to do yourself, at all.

Busa mav

2,562 posts

154 months

Sunday 22nd January 2017
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Surely the first thing is to drain the system, drop the rads and flush them out, that's where the crap will be, then start with a refill and cleaner for a couple of weeks.

Simpo Two

Original Poster:

85,321 posts

265 months

Sunday 22nd January 2017
quotequote all
guindilias said:
Gravity fed? Throw a pump on there and you'll get a lot less sludge - and faster heating up times. Then stick in a litre of X800 once you have your filter in, then dump the lot and add a litre of X100 when you refill.
Well, there's a Grundfos pump in the airing cupboard; what I meant is that the hot and cold water is gravity fed.

The radiators work well and heat up quickly, which I guess they wouldn't do if clogged up. I think removing them would be a massive and expensive job.

The hard part is knowing exactly where the problem is. I cleaned out the header tank before Christmas (another plumber who was too busy to attend suggested I drain it down a little and put some non-scidic cleaner in there, which I did to little effect) - and there was 1-2" of disgusting slimy clag and bits in there - so the system has been 'blowing its nose' for some time!

Simpo Two

Original Poster:

85,321 posts

265 months

Sunday 22nd January 2017
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NB So far this morning, from a cold standing start, it's working perfectly.

Fastpedeller

3,872 posts

146 months

Sunday 22nd January 2017
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FurtiveFreddy said:
I'm certainly not trying to make out that all plumbers know nothing about heating, but there's a lot to learn and keep up with when it comes to doing a proper job of installing and optimising a central heating system and I realised that once I (eventually) found a specialist who really took an interest in his job.

^^ Wise words. Taking an interest in the job is crucial - I've seen too many "highly qualified" who can't be bothered, so the end result isn't good. BTW, you can sometimes locate magnetite blockage in a copper pipe with a magnet! I kid ye not!

Simpo Two

Original Poster:

85,321 posts

265 months

Sunday 22nd January 2017
quotequote all
OK; I'll cast the net wider. Other than Google, how does one locate a 'CH engineer' and distinguish him from the others?

megaphone

10,710 posts

251 months

Sunday 22nd January 2017
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As above, take the rads off and flush them through with a hose, we did this on my 25 year old system before fitting the new boiler, got rid of loads of gunk.

Will also give you the chance to fit new TRV rad valves if you want.

roofer

5,136 posts

211 months

Sunday 22nd January 2017
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Rickyy said:
Personally, I would fit a magnetic filter to the boiler return, run a decent system cleaner through the system for a week or two.

Then drain the system, take the rads into the garden and flush them through with a hose pipe.
This is what i did to ours. The amount of crap that came out was unbelievable ! Also did all the pipework too, which was a pita, but worth the effort .

ColinM50

2,631 posts

175 months

Sunday 22nd January 2017
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Here's a guide to what's involved and how to do it. Seems quite a lot to it tbh, but not £500 worth. Had a quote from British Gas a couple of years ago for £600 and they saiod it'd be doen in a day, so a plumber and an apprentice, £600 a day. Wish I could get that

https://www.sentinelprotects.com/uk/support/guides...

Not sure where you can hire the relevant machine though. Maybe your local plumber's merchant might do it?

pim

2,344 posts

124 months

Sunday 22nd January 2017
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I would also buy a new boiler 1988 it has earned his keep.


21TonyK

11,513 posts

209 months

Sunday 22nd January 2017
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ColinM50 said:
Here's a guide to what's involved and how to do it. Seems quite a lot to it tbh, but not £500 worth. Had a quote from British Gas a couple of years ago for £600 and they saiod it'd be doen in a day, so a plumber and an apprentice, £600 a day. Wish I could get that

https://www.sentinelprotects.com/uk/support/guides...

Not sure where you can hire the relevant machine though. Maybe your local plumber's merchant might do it?
HSS hire the kit

https://www.hss.com/hire/p/central-heating-flusher

Simpo Two

Original Poster:

85,321 posts

265 months

Sunday 22nd January 2017
quotequote all
Thanks for the ideas; I'm certainly not going to hire a power flusher and do it myself!

Replacing the boiler isn't going to get the crud out of the system.

So we have:

Plan A - magnetic filter and bash the rads
Plan B - powerflush

Powerflush seems to have a slightly dodgy reputation as it can be used as a panacea to make money. More relevant, the fellow who came round said it could create leaks in an old low presure system - which makes sense to me - hence he proposed the filter approach. If he was after a quick buck he'd have gone for the powerflush, no?