Central heating with 10mm plastic pipes

Matt_Newton

Hi everyone,

I'm the process of getting some quotes for a reinstall of the central heating system in our new house in order to replace badly installed 8mm microbore piping. After the comedy of an exhorbitant quote from British Gas, I now have a couple of quotes on the table from two local CORGI registered installers. One of them appears to meet all of our requirements, but the plumbing to the radiators will be done with 10mm plastic piping. The installer says that he always uses this and there's no point in using traditional copper anymore. However, this does make me a bit uneasy on the basis of my subsequent investigations since its not going to be a lot larger than the existing microbore (especially the internal diameter is smaller for plastic) and the fact that plastic pipe seems to be used mainly for DIY or for particularly complicated installations. On the other hand, the same quote uses good quality components elsewhere (Worcester boiler and Stelrad radiators).

The other quote on the table is for traditional copper pipe (with 15mm runs to the rads, IIRC), and is more expensive.

Does anyone have any info on the pros and cons of plastic pipe vs copper pipe (especially at these diameters)? In the long run, is it going to be worth me spending more initially on the copper?

Thanks,

Matt

weekendwarrior

Spend the extra and use copper.

I use plastic in houses that I am goint to sell, but in my own home I use copper.

10mm plastic uses inserts and the diameter of the hole in the inserts is tiny, perhaps 6-7mm, so the 10mm pipe size is reduced at each joint.

Copper is tried and tested, bit more expensive, but much better imho.

There is nothing wrong with plastic pipe, so you can use 15mm plastic pipe and then use compression fittings, this will give you full bore and they are often better than push fit joints!

alanobrien

I have to admit i have always disliked plastic piping on a heating circuit. That said our loft conversion in the old place was installed using plastic pipe and it was fine.

My next door neighbor recently replaced their whole system with plastic piping. Advantages include less heat loss and lower cost installation, disadvantages....less robust than copper.

I am still unsure about it but would certainly consider using a plastic piped installation in future if necessary.

Nile

Hello Matt Newton

Welcome to the MSE site.:wave:

thescouselander

It all depends on the type of plastic pipe you get but some plastic pipe I have seen is only rated up to 4 bar @ 65 degrees C and this gets less if the pipe gets hotter than this. I'd say you could be working near to the pipes limits if you have a pressurised heating system if you're not careful.

Personally I would go with copper.

bestyman

Plumber here with 22 years experience. Most new houses use plastic pipe, 10mm plastic to rads is not unusual .
Ive seen 22mm copper pipes scale up, nothing to do with pipe size but poor system design and lack of inhibitor.
!0mm plastic will be fine.

EDIT 50 year guarantee, how long do you want it to last? Other info on this site http://www.hep2o.co.uk/

weekendwarrior

bestyman wrote:

Plumber here with 22 years experience. Most new houses use plastic pipe, 10mm plastic to rads is not unusual .
Ive seen 22mm copper pipes scale up, nothing to do with pipe size but poor system design and lack of inhibitor.
!0mm plastic will be fine.

EDIT 50 year guarantee, how long do you want it to last? Other info on this site http://www.hep2o.co.uk/

A guarantee is often not worth the paper it is written on!

If you go to one of the sheds and but a 10mm Hep20 pushfit joint and then take it home and use it on chrome pipe, there is a good chance that it will eventually blow off because the grip ring cannot grip the chrome. When you purchase the 10mm Joint it says nothing on the packing about this and often if you go to a plumbers merchant it will be a single joint that came from out of a bag of 50 joints, so no instructions.

So, you have a massive leak and try to sue Hep20 but you probably won't get far as pushfit is not to be used on chrome unless the chrome plating is removed first.

Remember scotch video tapes "guaranteed never to fade"?

This is one of the reasons that big companies like Hepworth and M3 corporation have tradenames, in 20 years when they discover faults with the pipe or fittings that can cost them millions of pounds to rectify they could close it down and open it up again under a different name. So you may then be purchasing Hep30 fittings, but this is nothing at all to do with Hep20 as they had faulty fittings, not like ours!

Like I said earlier the pipe is ok, but I would not trust the pushfit joints as they have o rings and could eventually fail.

Speedfit is also better than hep20 IMHO.

onedime

This has been a nightmare with our house.
I have a 12 year old house with 10mm Hep 2O plastic central heating pipes and currently have 3 radiators not working out of 10.
Oxygen barrier pipe is recommended for central heating but mine isn't and I could not get anywhere with the builder,NHBC warranty,plumbing contractor who installed the system,Hepworths or Sentinel(inhibitor)or British Gas (service contract)
Our hall radiator went off fairly early in the life of the system.
I have tried cleaning system by flushing through with desludger but each time I drained down system another radiator was knocked out.
British Gas were offering to Powerflush at about £750 with Magnaclean filter but stopped offering and finally said only solution was to repipe whole system at several thousand pounds cost(I forget exactly how much)
I think the pipes are simply not big enough diameter (as all central heating systems seem to sludge up to some extent even with corrosion inhibitor) and just block up.Some sort of filter to collect the sludge is also essential I think.
Any suggestions for rectifying my system appreciated.
I would not specify plastic pipe for heating systems , even oxygen barrier type.
I can see the advantage of plastic pipe to the plumber installing the sytem but I believe the finished product can only possibly be satisfactory with a pipe diameter bigger than 10mm.
Regards to all suffering from this problem -there must be thousands!

gas4you

I use plastic where copper would be impossible to fit in. I would always prefer copper.

50 year guarantee! if the pipe splits at 49 years 9 months, do you really think they will honour it?

For one, the receipt will probably have been lost, so no proof of installation, then they will blame system water quality or contact with another inappropriate material has caused it.

Don't forget also, that rats love plastic pipe. It's so easy for them to chew through when they sense water.

katalin_2

Has anyone used multilayer composite (MLC) pipes? I've heard these are better than plastic and copper, but that they also use o-rings that can come undone.
I need to repipe my flat as the copper pipes were laid poorly at construction 10 years ago (not sleeved properly, and unprotected from the screed) and now are corroded. So far I've had recommendations on copper, plastic and MLC and am undecided.

aboard_epsilon

One more thing you want to consider is ..what ever make of plastic pipe you decide choose ....in 10 year ..15 years ..who knows ..it will be obsolete ..with no fittings available for it ..and incompatible with the next trend.

i used plastic pipe, for the pipe over to my workshop ..the stuff was called Acorn........they ain't around any more ..and i have not checked weather it is compatible with any of the new stuff ..i suspect it isn't ...or does anyone no better than this .?

all the best.markj