Hi there,

Well, further to my last thread on my house purchase, i'm now about to complete and get stuck in! The subject of recent rapid research has been plumbing and there's a few areas i'd appreciate comments on from anyone with any experience...

1. One thing is the plastic vs copper debate for any plumbing I will have to do (moving rads, new boiler, new pipes to extended kitchen). The picture i'm seeing is that plastic is probably the inevitable future (but there are plenty of hangers-on to copper), and that it can be every bit as reliable as copper if installed properly. The main advantage of plastic is of course the ease of installation and servicing. Anyone have any experience/words of wisdom to offer on that one?

2. Also considering the type of system. Currently it's an old back boiler and hot water tank in the roof. Obviously the back boiler has to go but what should replace it? Conventional boiler keeping the existing hot water tank or go combi and have everything mains fed? It's a 2-bed bungalow with just me and me partner (to start with) so shouldn't be too much simultaneous hot water demand, though we do like baths every now and then. What other factors are worth considering?

3. Finally i'm considering layout. In addition to the conventional layout of main runs teeing off to appliances/taps i've seen (mainly on american sites) this manifold block layout. You have big manifolds at the mains supply/water heater location then individual pipe runs from the manifolds to each appliance/tap. I've only seen this in plastic systems and the advantage seems to be a central location for shutting off any individual part of the system and no fittings anywhere except the manifold location and the appliance/tap ends. Disadvantage is the much larger number of pipe runs to install - i guess the reason i've only seen it in plastic. Perhaps this is really something for a new build only? Any comments on that?

Once again all advice much appreciated!

Cheers,

Liam

i run all pipe that is not seen in plastic as is so easy dont need to pull bends. but i use compresion fitting on the the pipe as some time when you drop the pressur cant spell sorry the fitting can weep and if under the foor its a pain to sort out

Go for plastic...so much easier for the DIYer.....and given the price of copper....must be cheaper?


Have you considered a heat pump for your heating and water needs? (Means you could also fit underfloor heating....which is seriously efficient compared to radiators)..


I dont see the point of the manifold system...it just means that you have to have more pipe runs....thus spend mroe on materials...

I can see it being quite handy on a high demand property where, someone having a shower halfway along a supply run might effect everyone else.....but in such a small house....whats the point!

Yeah the manifold block layout does seem a bit gimicky - probably another reason i've only seen it on american sites!

So...er...what's a heat pump exactly? Is underfloor heating all that awesome? The house is 30s construction with ventilated floor voids and floor boards over. Can underfloor heating be installed in voids or does it have to be in screed? (could i just fill the voids with screed? will the vent bricks mind?). Hmmm now you've opened up another can of worms I love the idea of no radiators...

Liam

[Edited on 12/6/08 by Liam]

you have U2u

I got a bit of both but prefer plastic. Try to get the main pipe from boiler mains and hot water running in a central location in the house and tee off from that, keep joints to a minimum and try to fit where you can gain access if needed. I would fit a condensing boiler. Make sure you lag everything as this will save heat and cost. I ran the hot water to my bath in 15mm pipe fills quick and doesn't run cold due to demand.

Off the top of my head, before I go to bed:
You cant use plastic pipe to connect up a boiler. You need a minimum run of copper due to the heat.
Plastic is easier to run than copper, but can look less attractive if you need surface runs.
You can also make much tighter bends in copper (with the right tools) than you can in plastic.
Plastic is more susceptible to attack by vermin (rats and mice) trying to get to the water than copper.
I used a mix of each, with high-end push-fit connectors, and it was an absolute breeze compared to using just soldered joints and copper everywhere.

I'd go for copper, but that's cos that's what I was taught to use many moons ago. I can't see plastic lasting as long though it's no doubt quicker to fit.
Anyway bending copper pipe is good practice for making your own roll cage.
The guy who taught me could work wonders with soldered joints and lead pipe so don't call me old-fashioned.

Polyplumb or the like is literally childs play, it's just like meccano only probably easier. As above you can't use it too close to the boiler but I'm pretty sure it's only one metre or so!. The only thing to be wary of is using the joint more than once as the grab rings in the join pieces can get a bit warped if you take them apart and re-build them.

My daughter's dog managed to chew a tiny hole in the plastic pipe to a radiator... not easy to fit (harder to fix than copper, anyway).

use speed-fit twist and lock push fit fittings from screw fix ...... top job .... if you use the plastic pipe remember to use the inserts

IMO, I'd use, and do use, copper and proper soldered joints, can't leak when done properly. Plastic hardens with time, I just pulled some out of my daughters house last year, don't know how long it had been in but, it cracked very easily.

Mechanical, (non soldered) joints are always prone to differential expansion with heat and every one is a potential leak.

Just my opinion for what its worth....

I was just about to mention the inserts!!
I've done lots of plumbing in lots of houses. New builds, renovations, barn conversions, extentions etc...
You can't beat plastic for speed and simplicity. Just mark the pipe with a pencil to make sure it's pushed in far enough. Most plastic pipe already have little arrows or gradients marked on so as long as you cut the pipe on the marks, and the fitting is pushed up to the corresponding mark, it should be on.
Any exposed pipework, I do in copper. Any work in airing cupboards or up to radiators, do in copper. Don't forget, you can push copper into plastic fittings. Plastic looks untidy and it doesn't paint well!!
The first 300mm from a boiler should be in copper.
The manifold system isn't worth the grief of extra pipe!
Run the hot to the bath in 22mm if the run is fairly long as the water will be cooling and therefore loosing pressure if it has a long way to go in 15mm!
If you have a mixer shower, feed the hot and cold from the same place to avoid any pressure difference (usually the same tank to feed the hot water tank and the cold for the shower). Unless you are going all combi............
Heat pumps involve pumping a chemical (ammonia and other substitute stuff) into the ground where it picks up a bit of heat which is then converted via the heat pump like a reverse fridge. It can be expensive to buy and set-up and in a small property, you may struggle to save any money in the next 10 years. But still worth a look!

[Edited on 13/6/08 by owelly]

like every one has said use plastic where hidden and copper where seen. On plastic make sure you use inserts and i always use something called a collet clip its there to stop the fitting opening on its own if you putting plastic on any mains or hot water on a combi make sure you fit a pressure reducing valve on the mains plastic is only garanteed to 3bar even though tested to 10bar. heat pumps are very good but very expensive and in most cases you need a back up boiler to. also with a heat pump you need too dig all your lawn up run pipes and alot more in short not worth it. as with the boiler it has to be condensing now you cant fit anything else solar power is better and cheaper then heat pumps but is still expensive as for the manifolds you are going to have alot of long runs with them so it will take longer for the hot water to come through if you go for combi get a good one there is a big difference either vaillant or worcester bosch i recomend min distance from the boiler in copper is 1000mm but make sure you check in the instructions any more questions u2u me cheers adam

ps never seen proper hot cold water plastic pipe crack the only thing i can think that other bloke is on about is in about the 70s there was a shortage of copper pipe and other metals so they used overflow type pipe that you glue but this is very rare and if you have it get rid of it

[Edited on 13/6/08 by adam1985]

Super-duper-super! Thanks folks - it's all much clearer now (apart from the new can of worms: do i put in the work and go underfloor heating and loose the rads ).

Hmmm - can't think of any more questions for now...

Liam

underfloor heating is meant to be much better than radiators, as it warms from the bottom up. You also end up with very insulated floors as this is part of the system, with rads you might not bother insulating the floors.

I dont like plastic pipe and fittings, but i do appreciate their advantages when putting runs under floors. I wouldnt put any hidden plastic fittings in though.

im a big fan of copper (use it every day)
if you do go plastic you could use a manifold to rid the need (hopefully) of joints under the floor
i have used plastic in the past and have had one fitting blow so i try to stick to copper

at the end of the day the choice my friend is yours

BTW
dont even think about underfloor heating
just get it fitted you'll never regret it
HTH

quote:

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Originally posted by Liam
Super-duper-super! Thanks folks - it's all much clearer now (apart from the new can of worms: do i put in the work and go underfloor heating and loose the rads ).

Hmmm - can't think of any more questions for now...

Liam

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Just a quickie, plastic pipe is not only guaranteed for 3 bar pressure, it's guaranteed for 25 / 50 (depending upon application) years at the working test pressure, usually in the region of 7bar 95°c.
We recommend a metre of copper to connect to the boiler, then the rest of the system in plastic. Copper is getting very expensive now and although it will probably outlast plastic, I'd only use it for longer horizontal runs where you can see the pipe.
Underfloor heating is great. Check out here
for an idea for simple UFH. I did all the development work on this, so I'm a bit biassed

cant agree on the last comment as the manufactures told us to make sure it doesn t go above 3 bar and fit a prv

I am a manufacturer

Wow cheers folks!

Just another quickie - do you normally bother fitting an electric shower if you have a combi boiler system?

Cheers

Liam