New Central Heating SYstem - Is it wise to use pushfit?

[hns123]

Hello Plumbing Forums

I am having a new central heating system installed at my house. The new system will consist of a worcester bosch greenstar 27 cdi combi boiler, 12 no radiators (compacts), 11 thermostatic radiator valves. The system will be sealed, unvented.

The pipe work will be mostly run under floorboards, the only place where it will be seen is at the radiator points, at the boiler and at the radiator in the kitchen - concrete floor here, so it will have to be run above ground for around 1.5m.

The plumber doing the work wants to use speedfit pipe and fittings, we've had a few talks about this but i remain largely undecided. He has said i can have copper pipe and fittings if i want but he recommends the plastic.

I've been told that plastic fittings can be unreliable over time and also should not be used on a pressurised system.

Can I please have some thoughts on this subject.

Thanks very much

 

[newbie1]

he wants to use plastic because its quicker to pushfit then solder i dont know of many people that prefer plastic fittings..i personally would have the copper every time..flame suit on but pushfit is more for convenience and speed and can cause problems if the fitting gets disturbed

 

[garry]

i agree i use copper most of the time i fitted a mixer shower a couple of months ago and the customer wanted plastic fittings which i used but one elbow under the shower tray keeps weeping i have been back four times now it stops for a few days then starts again am going back tomorrow again to rip it out and put copper fittings in its place as he waiting to tile the floor a right pain in the a**e and not in the easest places either. Just glad its not one of the ones i put in the wall and covered due to plaster and tiling on the wall finished.

 

[CharterGAS]

DONT USE SPEED FIT YOU WILL HAVE PROBLEMS

use polyplumb or hepworth but make sure the installer does a hydrostatic pressure test and all will be good

 

[leakylea]

I,ve been to two jobs in the last week where plastic has failed, sadly the first job will require the complete distruction of a beautifully finished bathroom to access one fitting that has devastated the down stairs flat.
Copper looks the nuts if the bloke putting it in is a plumber.The extra time putting it in is usually time that the tradesman finds all the little bits and pieces that makes your job unique,thetime he takes to produce a neat job will mean a greater working life of the appliance, and he will be more likely to stand by his work,

 

[GPS164]

Steer clear of plastic fittings! I hate plastic! Even plastic backnuts, plastic threads on ballcocks etc.

In my view plastic pipe is ok for an awkward run of pipe if you use compression fittings at both ends, but push fit fittings are more hassle than they are worth...regardless of the brand. They are unreliable and the preferred choice of a have-a-go "plumber".

 

[hns123]

Thanks for all the responses.

I am seeing the plumber later on today so I will definitely be going for copper pipes and fittings

Thank you.

 

[paulplumber86]

Ive got to agree with copper..


However, weve done dozens of heatings in plastic. Some dating back a few years not without any problems. We came off the boiler (22mm copper) to 22mm plastic to 2 central manifolds. Then piped the rads from the manifold with 2 continuous lengths of plastic. So apart from the rad valves and manifolds theyre wasnt any joints or fittings used.

All worked fine, no pipework on show at any of the rads and alot quicker.


So im not anti plastic like most here!!

 

[stevetheplumber]

have used a lot of plastic for heating, my favourite for new builds is manifolds and 10 mm pipework
advantages are
can be cabled in from below
no joins in floors
no visible pipework to rads
pipe work can be lost behind dry lining
low water content gives fast heat up
for existing buildings i use15mm plastic below floors and come up with copper

 

[garry]

im not anti plastic i agree it is easier in new builds with pre drilled joists cos they never are in line its not all plastic but am not as conident with plastic joints as i am copper you can see when the joint is sweated properly you just av to hope with some plastic fittings.

 

[stevie t]

Hi,

Ive been using plastic pipework, manifolds, fittings and their inserts for years and I would recommend them everytime. The brand i use in particular and stick to is John Guest Speedfit but this is a personal choice.

Without sounding like a salesman for all that is plactic let me say if your htg engr hasnt alreadly:

* all plastic materials are factory tested by its manufacturer to 10bar. Ur htg engr can test and show u ur current domestic water pressure at the mains supply, demonstrating to u 10bar is v high pressure putting your mind at rest, indicating fittings are unlikley to blow off. **Must add I have witness this in burst pipes both plastic and copper,
*plastic fittings are more expensive but the speed at which plumbers can work is greater than using copper. This wont make job cheaper in anyway as it evens itself out in the end,
*lime scale in your area? well as far as i'm aware plastic dont do limescale build up or significantly reduce it anyway. Should u have limescale in ur area (tell tale signs: look in your kettle see if theres a hard white build-up clinging to the element) your plumber can fit a limescale reducer reducing limescale build-up in your boiler that would otherwise causing "kettling",
*plastic is a lot tougher than u think especially with its medium density barrier protection,
*your less likely to get a burst pipe as plastic will expand slighty whereby copper wont. However see ** first comment above,
*no heat loss thru plastic. Copper/metal is a heat conductor u can physically feel difference on hot water pipework where plastic and copper is used,
*1 metre copper tails should come off the boiler at the flow, return and domestic hot water. That said I run off at least 1 metre tails from boiler inlets/outlets regardless. Gas pipework and fittings should always be copper nvr plastic as per Gas Regs, but ur htg engr will know this,
*best to use 15mm as opposed to 10mm. 10mm and 8mm is a non starter for me!



Hope u find this helpful

Note for DIY'rs using plastic. Cut pipework flush across the diameter with the proper cutters leaving no burrs - dont use hacksaws!. Ensure pipe ends are pushed fully home into their fitting and hand tighten. Dont mix and match various plastic types and always use the correct pipe inserts.

stevie t, belfast

 

[Blackcatgas]

A bit of plastic is ok, I will however use copper, mice and rats love chewing through plastic pipes.

 

[ecowarm]

I've seen plastic pipe nibbled by mice until it leaks under floors and roof spaces

 

[pauls]

i would go for copper i done one in plastic custard wanted cost lowered so gave him the plastic option ive never slept properly since

 

[Billy Bob Bob]

copper do it proper

 

[Mbear]

i would go for copper i done one in plastic custard wanted cost lowered so gave him the plastic option ive never slept properly since

Work to live mate not live to work. Get some gd zzzzz's in

 

[Bernie2]

Copper myself. I have had push fit blow off, you just don't know with them. Some guys think they are great though.