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countryman69

Around 20 years or so ago and shortly after Hep2o came on the market, I installed the central hetaing system in our house using a mixture of Hep2o plastic (no barrier available then) and copper. Although inhibitor was put in (and regularly refreshed) I'd not heard anything about haematite.

It's a big house and so some rooms have very little CH flow through them. Over the years I noticed a gradual falling off in efficiency with some rads not getting very warm. Investigating further I found at least one of the pipes blocked with this black gunge. Interestingly, the copper pipe that this plastic pipe was connected to was perfectly clear.


hep20.jpg

I put this down to haematite in the system but surprised that it deposited itself only in the plastic and not the copper.

I mentioned this today to the engineer who came to do the annual service on the oil boiler and his response was that the 'original Hep2o decomposed which was why they introduced barrier pipe'. Googling hasn't really come up with anything to back up his claim and so I thought I would ask the experts here.

Since discovering the blocked pipe in the picture, I've power-flushed the system and installed a Magnatite which does need an annual wipe down as there is a build-up of a slight film of haematite.

Supplementary question, if I may. I fitted Acova Striane radiators which have a very narrow internal bore. I recently took one of them off to do some replastering behind and thought I'd flush it out with the hose. I was surprised to find that it had sludged up a bit as forcing mains water through pushed out a fair bit of black and shaking the radiator from side-to-side seems to flush out even more. So I'm wondering whether I should take off all the radiators and repeat the same flushing.

Bit stumped really as to the best way forward.

Any advice gratefully received.

Thanks
 
Re: Does original Hep2o pipe decompose?

The old pipe was porous and subsequently allowed more air to enter the system than copper and barrier pipe. This greatly increases the reaction between air ferrous metals.
 
Re: Does original Hep2o pipe decompose?

I have never heard of Hep20 "decomposing". What the non-barrier polybutylene (PB) pipe does allow is the ingress of oxygen through the pipe wall, which is why it is not recommended for heating systems, but is fine for (for example) domestic water service, where the water is already likely to be heavily oxygenated.

The oxygen that will have entered via the pipe wall will have reacted with any ferrous metals in the system (rads, iron pipe or boiler hex) to produce the black sludge. Where is settles is sometimes a physical property of the system design, rather than whether the pipe is copper or PB.

If the system has been flushed and you have added a magnetic filter, thats probably all you can do, short of replacing rads and pipework. It won't be perfect, but it has given 20 years of service already.
 
Re: Does original Hep2o pipe decompose?

The non-barrier pipe was found to be porous to oxygen in very small amounts - so small that it would be unlikely produce significant corrosion in a heating system over its normal life (25 years). However, around 25 years ago, British Gas were troubled by the mention of corrosion and ingress of oxygen, in regard to their installation contracts. Thus, to satisfy BG, the barrier pipe was introduced for heating systems. Hepworth, had to get BG using the product so others would follow suit - it worked!

In regard to the problem, the power flush etc just treats the symptom. If you have excessive production of magnetite in a heating system, then the 'root cause' needs to be found.
 
Re: Does original Hep2o pipe decompose?

Many thanks for the replies, chaps. I think my first line of attack must be to remove the rads and flush them out.
 
Re: Does original Hep2o pipe decompose?

Just looked at the pictures again, the original stuff was Brown pipe and fittings.
 
Re: Does original Hep2o pipe decompose?

Just looked at the pictures again, the original stuff was Brown pipe and fittings.

Are you thinking of Acorn, which was Hepworth's original cold water only pushfit system? I don't think Hep20 was ever brown.
 
Re: Does original Hep2o pipe decompose?

Are you thinking of Acorn, which was Hepworth's original cold water only pushfit system? I don't think Hep20 was ever brown.

Have seen Brown pipe and fittings(15 only) on ancient systems identical to the old demountable hep. It maybe acorn, bit before my time to be honest . I did ask an old timer at the time and was told it was the original hep this may be incorrect though. On a seperate note, has any one ever seen or could shed light on glued heating pipes on a domestic system?
 
Re: Does original Hep2o pipe decompose?

Have seen Brown pipe and fittings(15 only) on ancient systems identical to the old demountable hep. It maybe acorn, bit before my time to be honest .

Cheeky young whippersnapper! :)

Acorn was the fore-runner of Hep, and was made by the same manufacturer. The fittings look like they are made out of bakelite. Or is that before your time too! :)

On a seperate note, has any one ever seen or could shed light on glued heating pipes on a domestic system?

Probably Polyorc. Brittle as hell, and an absolute pig to work with although you can still get adaptors for it. Was used in the late 70s and early 80s (?) during the copper shortages.
 
Re: Does original Hep2o pipe decompose?

Cheeky young whippersnapper! :)

Acorn was the fore-runner of Hep, and was made by the same manufacturer. The fittings look like they are made out of bakelite. Or is that before your time too! :)



Probably Polyorc. Brittle as hell, and an absolute pig to work with although you can still get adaptors for it. Was used in the late 70s and early 80s (?) during the copper shortages.

Thanks Ray. Yes bakelite, vacuum tubes, chokes and asbestos are all before my time thankfully. Have only seen the glued stuff, I haven't had the pleasure of working on it and by the sounds of it hopefully never will.
 
Re: Does original Hep2o pipe decompose?

I ve come across this once before. Went to look at why one rad wasn't working on an otherwise perfectly performing system. After a lot of messing about taking the rad off, checking the valves etc etc the owner mentioned that a few years back he had put a nail through the copper flow leading to the rad. He lifted the board cut out about 2 foot of copper and replaced with non barrier plastic pipe and two push fit couplers.
I took it apart at the couplers and found the 2 foot of plastic completely solid with black gunk. The copper either side of it completely clear!
Never liked plastic pipe, disliked it even more after this.
 
Re: Does original Hep2o pipe decompose?

Thanks, Sam....that is exactly the conclusion that I came to.

I now think that the idea of decomposition is wrong but that for some reason the black gunk prefers to drop out of solution in the plastic - which was my initial conclusion. It would be interesting to put two lengths together - one plastic and the other barrier to see if there is any difference.
 
Re: Does original Hep2o pipe decompose?

Old Hep pipe had a 10 year guarantee only. New Hep barrier pipe has a 50 year guarantee. Air is causing your problem with corrosion.

We carcass with Hep mostly, just in the floor bringing out copper tails. I think it's good stuff personally, easy to work with and serves it's purpose well enough.
 
Re: Does original Hep2o pipe decompose?

But what was it guaranteeing? Surely that it would not leak. Or does it start to let air through more and more as it gets older?
 
Re: Does original Hep2o pipe decompose?

Old Hep pipe had a 10 year guarantee only. New Hep barrier pipe has a 50 year guarantee. Air is causing your problem with corrosion.

We carcass with Hep mostly, just in the floor bringing out copper tails. I think it's good stuff personally, easy to work with and serves it's purpose well enough.

But what exactly is this 50 year guarantee with Hep? I think it really just covers against manufacturers defects. In other words, not much.
 
Re: Does original Hep2o pipe decompose?

But what exactly is this 50 year guarantee with Hep? I think it really just covers against manufacturers defects.

But what else can a manufacturer guarantee? World peace?

:)
 
Re: Does original Hep2o pipe decompose?

Well I'd suppose your probably right Best, it's not what I'd fit in my own house unless it was free lol but it should last plenty long enough. Long enough to be a paid job to put right haha
 
Re: Does original Hep2o pipe decompose?

Just saying, everyone reads the "50 YEAR GUARANTEE" and thinks, wow! - that's got to be so good and it will never give trouble!
Fine print will say, " against manufacturing defects", which might mean, - " You got a leaking or broken fitting or pipe? Sorry! Wasn't really what our warranty covered! We made the thing properly and it is just wear and tear, or not installed correctly, etc, etc."
 
Re: Does original Hep2o pipe decompose?

I ll never be convinced it's as good as copper as some people suggest. When I was with British Gas they were insisting we used it to the extent that of all the pipe you got from the merchants 20% of it had to be hep or you were penalised for it. It definitely has its place but if it can be copper it should be in my opinion.
Just out of interest does anyone know if the fittings suffer from air entrainment like the non barrier pipe used to?
 
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