# Central heating pipe - Is plastic bad?



## jimmy rivers (10 Mar 2015)

Swimbo has us signed up to British Gas Homecare..not entirely convinced myself but anyhoo's...

We moved in end of last summer and when we fired up the system only half the rads worked due to corrosion blockages in the pipework. I initially thought this was due to rads being isolated (at both ends) in the unused rooms. 

Had an engineer out to look at a section that was blocked dead. She had a go but after no luck said it was blocked due to the pipework being plastic... because the plastic pipe allows air into the system which contributes to corrosion which in turn causes the blockages. She said a power flush would be a waste of time as it would happen again and again and that the only solution is to replace the pipework and fittings with copper (£££'s  ) . 

When she left I went through the problem section of the system, pulling it apart and re-push-fitting until I got it all unblocked and running again...it was a PITA and took me two days. I topped the system up with inhibitor and cleaned out the MagnaClean filter. Job done.

5 months later our boiler has been mis behaving so a new BG engineer came out and replaced a part (not related to muck in the sys). Afterwards he asked how we found the system, as he'd been called out a few times prior by the previous owner. 

I updated him about the blockages and repairs and he said..._'Well - it's the plastic, you need to replace IT, AND the fittings to soldered copper, it's going to happen all the time'. _

I queried _'It's HEP2O barrier pipe...and I've read it's been approved by BG for CH systems? '_ 

He said _'it doesn't make any difference, it gets in at the fittings...' _ :| 


Are BG fishing for business?...is it a plumbing snobbery thing?...surely if plastic was that bad they'd stop using it on new builds?! 



SO...We're now not sure what to do... #-o 

We don't really want to be flushing the system every year at a £300 - IF it blocks... but in the same breath, we don't fancy forking out a fortune to replace :shock: in copper. The house is an old property and a very unusual layout, so I expect to replace the pipes could be pricy due to a complex install, which is possibily why the last owner went plastic due to it's bendy abilities.

A bit long winded...if anyone's got this far...and has an opinion on this plastic to copper topic...thoughts would be most appreciated?

Cheers Jim


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## Racers (10 Mar 2015)

Sounds like BG need to make money to pay for the adverts.

Pete


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## blackrodd (10 Mar 2015)

First I've heard of it! there's a plumber or two on here, perhaps hear what they have to say.
Regards Rodders


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## flh801978 (10 Mar 2015)

I have used it in my house for 7 years or so and installed 2 complete CH systems in daughters houses with it and never had a problem or heard of the problem
I dont see how air can get in via an O ring seal when theres 2-3 bar water pressure inside
Ian


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## Phil Pascoe (10 Mar 2015)

Racers":10omvwsi said:


> Sounds like BG need to make money to pay for the adverts.
> 
> Pete


I was advised years ago not to deal with plumbers or electricians who advertised in Yellow Pages.


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## John15 (10 Mar 2015)

Beware plastic central heating pipework. Two years ago I had some improvements done including a new boiler and re-routing some of the pipework below the floor in plastic. About a month ago the boiler lost pressure so I called out the plumber. He soon discovered the loss of pressure was do to a leak in his plastic pipework - it had been chewed through by mice!!

John


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## lurker (10 Mar 2015)

BG have a well known reputation for telling people that this or that needs replacing as the technicians ( they are NOT engineers!) are all on sales bonuses.
I would not let them on my property bunch of scammers the lot of them!

Find a plumber by recommendation and once you are happy with one treat them like a minor deity


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## graduate_owner (10 Mar 2015)

I installed my own system about 20 years ago using copper mainly, but with plastic where there were routing difficulties. I have not had any blockage problems, or at least I am not aware of any. I do get air gurgling in the radiators which need bleeding regularly, there is one particular radiator that seems to collect most of the air, but no blockages. There is no microbore used, 15mm is the smallest. Also there is no filter.
I will be having the old boiler changed soon and will fit an auto air vent when the system is drained down, hopefully that will be an improvement. I want to have a magnetic filter imstalled at the same time.

So from my own limited experience, no problems with plastic, but then no mice either (I hope)


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## jimmy rivers (10 Mar 2015)

Some good feedback thanks guys.... It's sounding like hot air from BG guys/gals (hammer) ...In support of this...the 1st engineer a few months back suggested that now that it's 'logged and recommended' that I should run copper in place, they 'may' not repair or replace parts damaged if the cause is from a suspected blockage... Forcing an unnecessary upgrade?

The engineer (technician) today said his manager '_might_' be in the area tomorrow and could visit to provide a quote on new pipework... I hope he hasn't delayed the parts repair till tomorrow so his manager is available...my wife is heavily pregnant and we have... no heating or hot water! :shock: just... two cats (no mice  ) and a log burner :roll: 

Mal Practice? Conspiracies? :lol: :? 


In theory if the system has a good glut of inhibitor in it and a MAG filter to catch the deposits before they build up we _should_ be fine. I guess (like I suspect many Brits do) we have naively signed up with a BG check and approve existing and assumed my plumbing to be then covered for disasters. After the 1st engineer comment I'm quite doubting BG will cover me if the big brown stuff hits the fan! ...ha!

I'll be keen to move to a good local recommended plumber at the end of the year like lurker suggests, I'll make sure I've a good selection of AAA biscuits :-D


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## themackay (10 Mar 2015)

I installed my own system about 20 years ago using hep 2 0 pipe started blocking up at the extemities of the system after 5 or 6 years none of the "experts" could tell me why, it turns out the hep20 pipe used at that time was not barrier pipe oxygen entering through walls of pipe I eventually replaced with barrier pipe about 12 years ago has been ok so far


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## Water-Mark (10 Mar 2015)

Send an email to the manufacturers with BG's report and quote, i'm sure they'll be thrilled.

I'm a plumber and have used hep and speedfit extensively in all applications and never heard of this.

How can it let air in and not water out?


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## Lons (10 Mar 2015)

It's a load of b**cks IMO and smacks of malpractice.
I've used it extensively for years and providing the correct quality pipe and fittings are used it's a reliable system.
if air is getting into the system it's likely to be entering on the "suck" side of the pump and liable to be a compression fitting. Most of the corrosion will come from the steel radiators and of course the more air in the system the more corrosion but this will happen in a copper installation as well.
BTW I've seen many a soldered joint fail (never seen a mouse chew though one though :lol: )


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## blackrodd (10 Mar 2015)

Water-Mark":36z3wa18 said:


> Send an email to the manufacturers with BG's report and quote, i'm sure they'll be thrilled.
> 
> I'm a plumber and have used hep and speedfit extensively in all applications and never heard of this.
> 
> How can it let air in and not water out?




I wondered that! 
Also speaking to the works plumber, any awkward or badly designed system will need the pump speed higher, which makes more air in the system and blockages.
When my combi was fitted, I had been to an auction and bought several bundles of copper, 22mm and a few 15mm tube
and most of the fittings. So quite lucky.
regards rodders


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## Doug B (10 Mar 2015)

Water-Mark":3atg306x said:


> How can it let air in and not water out?



Water tight doesn't automatically mean air tight.
Interestingly I've got to go look at a job next week, a 20 year old central heating system on which the radiators keep developing leaks, half of the radiators on the system have had to be changed & the system is very sludged up. The property is on a newish housing estate & several of the homeowners have had the plastic pipe work taken out & replaced with copper,
There are no signs of leaks but the combi boiler has to be topped up weekly & as all the pipe work is in ceiling voids or behind plaster work any leak would show up pretty quick. Even with the combi isolated from the heating system pressure is lost, I envisage a little head scratching coming on.


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## Water-Mark (10 Mar 2015)

I've seen plenty new build microbore systems weep at joints and valve glands, the water evaporates with almost no evidence of water damage.

How i hate microbore, plastic or copper.


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## jimmy_s (11 Mar 2015)

The oxygen enters the heating based on differences in partial pressures on either side of the pipe wall. Hep has a barrier layer to help prevent this so you should not have much oxygen get through. The oxygen getting through the fittings will be minuscule I would think. The mice are quite partial to Hep - I was told it was to do with the oils used in manufacture.

Once there is crud in the system the water can act as an electrolyte creating galvanic corrosion - if the boiler has an aluminium heat exchanger this can be a problem - the corrosion byproducts are from memory a gray/brown colour - the water is cloudy with a very fine particulate in suspension. We had this recently on a newish block of flats with a communal heating system that operates at low temps. This system was piped in steel tube so no oxygen issues and it still ended up with corrosion.

The other type which is more common is black crud that mainly gathers in the radiators - a mixture of iron oxides I think. We have had bother with this recently as well on a school where the entire heating system was replaced in phases over 21/2 years. Traces of crud from the old system seem have been left in solution as it was commissioned in phases. The black crud seems to increase in quantity quite quickly once it gets a hold, we also found the corrosion process created some gas which tended to gather in the radiators. Again this was a steel pipe job so no oxygen diffusion issues. 

In both cases the heating systems were re flushed after allowing a chemical cleaning agent to circulate for some time then dosed with inhibitor.

If your heating system is open vented and you have a leak then over time that could allow oxygenated water which may increase corrosion. You will tend to get more crud from in an open vented system as the F&E tank is open to atmosphere allowing oxygen to enter the system in any case.

I knew a gas fitter who worked for BG - he left. I understand they get training to sell services to the customer etc, he didn't like the selling bit and got another job.

If your system filling with crud again I would find out what the boiler heat exchanger is made from and then get a suitable cleaning chemical from Fernox or Sentinel and dose it with that, run it for the recommended time then flush it out. Sometimes its hard to flush all the muck out of the radiators. Most crud gathers in the radiators as the water is moving quite slowly through these. If need you can drain the system and remove the radiators then flush them outside somewhere with a hose through the valve tappings. You need to get rid of all the crud otherwise it can begin to corrode quite quickly again. Once properly flushed out get the system dosed with a suitable inhibitor and you should be fine.


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## porker (11 Mar 2015)

One point that was mentioned earlier in this thread is that some of the pipe (particularly earlier stuff) allowed oxygen to pass through the walls and it was not recommended for CH applications. That is not the case for barrier pipe which is the majority of the stuff now. It took me a long time to trust plastic but I am convinced its good stuff now. I try not to put any fittings where they can't be accessed and I have to watch the rodent issue but no problems with this so far.


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## jimmy rivers (11 Mar 2015)

Thanks for the feedback guys...fortunately no manager/sales rep visit with BG engineer (tec) today. The forum advice has been reassuring so in the meantime we're gonna sit it out with our current pipework and brief the cats on a patrol route... :lol: All is repaired...heating is on... now...


...dare I look to see if he's replaced all the screws to the boiled cover panel? :roll:  (hammer)


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## finneyb (11 Mar 2015)

jimmy rivers":10ryadpg said:


> I updated him about the blockages and repairs and he said..._'Well - it's the plastic, you need to replace IT, AND the fittings to soldered copper, it's going to happen all the time'. _
> 
> I queried _'It's HEP2O barrier pipe...and I've read it's been approved by BG for CH systems? '_
> 
> ...



It's a plumber's closed shop issue. Any DIY dimwit can push fit plastic, provided they put the inserts in of course, whereas it takes more skill to solder copper. It takes work away from the tradesman - it's a bit like supermarket checkout people not using self-scan because it threatens their job.

Suspect Solicitors do it with Wills and House conveyance

My 2p worth

Brian


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