Plastic pipes v copper pipes!

[Vikki]

Hi

I hope someone can advise me here as I am totally clueless!

We moved into our house about a year ago and inherited a baxi bac boiler and central heating system. We have decided to change the syste and have a combi boiler fitted and this will allow us to have a ne inset fire and get rid of the not so nice one that we have at th moment.

We have had BG out who have given us a quote which we are happy wit and they sent their surveyor out yesterday to measure up. It was al booked in for next week but as the surveyor was leaving he noticed tha all our pipework is plastic. They are now saying that they can't insta a combi and we can only have a normal boiler. We don't want a norma boiler as we want to get rid of the water tanks in the loft. My husban has spoken to some of his friends and they have combi boilers wit plastic pipes and can't see what the problem is. We have pulled up th floor boards so that we can see the pipes and they have written on the "12 bar/12c 7 bar/82c HBPUK PB" and we have been told that this is mor than okay for what we need.

Is the fact that we have plastic pipes a problem or not? If we get local plumber out to do it will it be okay or will it start leaking? I there anyway around the problem other than changing all the pipework?

Yours hopefully

Vikk

-- Vikki

[Owain]

This is excellent news as it allows you to dispose of the quote from British Gas and get one from someone else who will probably be 20-50% cheaper for the same or better.

Owain

[Calvin]

...

The general opinion here seems to be that BG will rip you off big time. I'd advise getting some other quotes.

pipework can't be plastic (the first section from the boiler must be copper). If there is a technical reason why you can't do this it won't be because it might leak a bit, it will be a safety issue related to what happens in certain fault conditions. Why not browse the manufacturers web sites, both plastic pipe and the manufacturer of the proposed boiler. Alternatively give the manufacturers technical departments a phone call.

[Now for some fun]. What does Dr Dribble think?

[chris French]

In message , Vikki writes

Well I suggest getting other quotes, BG have a reputation for charging well over the odds.

And this is an even better reason as he is talking absolute bollocks. Did he say why?

find as long as you are aware of the limitations of combis as well.

There isn't one, I installed a CH system with mostly plastic plumbing with a combi it was fine.

Yep. Sounds it. A typical combi system will run at about 1 - 1.5 bar with a maximum pressure of 3 bar.

No. The only consideration IIRC was that the first metre of pipe from the boiler had to be copper.

Yes.

No, it shouldn't unless it was improperly installed in the first place - a risk with any existing system though.

Yep, get someone who knows what they are talking about to give you a quote :-)

[daddyfreddy]

Maybe the plastic pipes are the older type without any oxygen barrier and that's what he is objecting to..or he's just a knob or thinks he can get more work by changing all the pipes as well. Regardless, use someone else, British Gas are rip off merchants.

[Calvin]

BG, bless 'em, have got a thing about non-barrier pipes. The trouble is that because they are (erroneously) trusted people tend to think that using non-barrier will inevitably lead to disaster. Just to be clear for the OP, even if they are non-barrier there shouldn't be an issue. They might lead to slightly increased corrosion in the system but not enough to justify the disruption and additional expense of removing already installed pipework.

[graham]

Give Worcester Bosch a call. We've had a Worcester Bosch boiler for nearly 20 years. It is still going strong.

When the engineer recently opened it up for its first service in 20 years, he said it is in perfect condition and he could see no reason why it shouldn't last another 20 years.

Worcester Bosch have a very good service / advice line.

If you are thinking of a new boiler talk to them about their range. I am sure they can also give you some advice about the plastic pipe issue.

Graham

[Doctor Drivel]

How odd. BG take on maintenance contracts fitted with plastic pipes. How much plastic is there? Is it on the Radiator circuit? Is it on the hot and cold water circuits?

[Christian McArdle]

Whilst I believe that BG prefer barrier pipework, there shouldn't be any difference between a combi and a system boiler, so it makes no sense that they would fit one, but not the other. Very odd indeed, particularly as it is the primary circuit (which is identical) that benefits from the barrier. The mains water supply is so full of oxygen already that a lack of oxygen barrier is of no relevence whatsoever in the actual hot water pipework.

Indeed.

Christian.

[daddyfreddy]

Best guess would be that they underquoted for the work and prefer the simpler option of just replacing like for like instead of changing the system and using any old crap excuse to do this.

[Aidan]

It pains me to say that I think BG are probably right. It's probably polybutylene tube (HEP2O?), but I don't know if it's a barrier type. If it is not barrier pipe, there's probably existing corrosion of the radiators and a lot of corrosion products in the primary side. The plate heat exchangers on combis have narrow waterways and are liable to get blocked with sludge. It may be some BG rule born of bitter experience.

The early non-barrier tubes have caused big problems with some UFH systems.

Yes, I trusted them once. Huge mistake, that I'll never repeat.

It will be an issue, but probably in some years.

[Doctor Drivel]

They don't take on non-barrier pipe CH systems. As long as the inhibitor is changed every 4 years there is no problem. Very rarely is this done.

[Rumble]

Had to look up the difference between barrier and n Pipe Selection

Hep2O® pipe is manufactured as two types, Standard and Barrier. Their correct applications are as follows:-

Standard Pipe

Standard pipe is suitable for domestic hot and cold water services and heating applications. As standard pipe may allow the ingress of minute amounts of oxygen molecules through the pipe wall when used for heating a suitable inhibitor (Betz Dearborne Sentinel, or Fernox MB1) should be used. Standard pipe is not accepted by British Gas for their service schemes.

Barrier Pipe

Barrier pipe is designed for central heating systems and incorporates an oxygen barrier to inhibit oxygen permeation. Barrier pipe is accepted by British Gas and must always be used where British Gas service is likely to be sought. The use of inhibitors with barrier pipe is still recommended as corrosion can occur in all types of system regardless of pipe material. Barrier pipe may be used for domestic hot and cold water services.