Central heating alterations

A couple of weeks back I asked on here about soldering joints on existing pipework. Having now had a good look around, i see that Conex et al produceflame-free copper push fit pipe fittings, which are less chunky and exactly what I need.

Also, Screwfix stock a plastic pipe system by FloPlast (Flo-Fit) at a good price. Does anyone have any experience of it?

(Screwfix is finally coming to Cornwall on November 9th!)

Thanks

Reply to
DIYer
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Check the temperature and pressure ratings. The pressure rating drops dramatically as the temperature rises. Plastic also needs to be well supported if you aren't going to get excessive sagging, over time, between supports.

Reply to
Dave Liquorice

Is that likely to be a problem with any of the plastic plumbing systems though and even a pressurised system is only run at 1 bar or so. Hep2O and Speedfit are fine.

I've no experience with flopast, it looks similar to Speedfit, which is fine. They have their own website if yoiu want more info.

True, and I'd not use it in visible areas where appearance mattered. but it's easy to install and I find it useful when working in awkward areas

Reply to
chris French

Why not just use solder fittings? I (like many) consider push-fit to be crap, especially on CH systems. Soldering really isn't hard, and will remain mechanically strong and leak-free for decades. Push-fit relies on rubber 'O' rings.

Reply to
AlanD

The problem that brought this about, was expelling water / steam in the existing pipework

Reply to
DIYer

IIRC the OP can't get the pipe dry...

Reply to
Dave Liquorice

There are always Cuprofit (IIRC) - pushfit for copper and the fitting is brass. Can be demounted wiht a special (but cheap) tool. Still has o-rings, but is otherwise bomb (and mouse) proof.

Reply to
Tim Watts

Solder the joint up dry on the bench, then attach it to the system with a couple of push-fits... ;-)

Reply to
Jules Richardson

If you've got mains pressure hot water, that can get a fair bit over 1 bar. (Without checking the ratings, I don't know if it's likely to be a problem.)

Reply to
Alan Braggins

Yup, they work ok, bit pricey though...

The fittings yes, the pipe no. Not been that impressed with FloPlast fittings - they seem to need quite high insertion forces to get a properly seated joint, and they are not at all tolerant of any misalignment on entry.

The pipe however may well be fine since I can't see much they could do wrong with that!

Reply to
John Rumm

Temporary fit Speedfit here - 4.5bar pressure on the hot water side, up to

60C, no problems.
Reply to
Tim Watts

I can't remember now without looking it up, but Hep2O was fine for the mains pressure water in our old house - and that had pretty high pressure.

Of course this ha smade me go and look it up :-)

for Floplast it gives a max working pressure of 12 bar at 20C

at 85C, 4 bar

Reply to
chris French

Anecdotally, no. In our old house I used it quite a bit and it had mice but we had no problems with nibbling. I've had abit in this house for a couple of years (running a temporary replacement supply out through the old stable and that's also fine.

Reply to
chris French

I have seen copper pipe fail after less than 20 years and fittings that never worked, I have yet to see any plastic pipe/joints/fittings fail even in heating systems. I have plastic pipe in my heating system, its ~29 years old.

Reply to
dennis

So says the bloke who still see the fairies in the bottom of his garden.

Reply to
ARWadsworth

Hmm. In the middle of the night when the mains pressure might reach

10 bar in some areas you won't be running hot water through it, and you won't run your hot taps or shower at 85C. But I think you would want to be cautious about how close you ran it to a combi boiler or thermal store heat exchanger.
Reply to
Alan Braggins

This is true. One set of boiler installation instructions I read said to take the last bit (1m, IIRC) in metal pipework and not plastic.

Reply to
Tim Watts

That is to limit damage when the boiler decides to keep firing after the stat has broken.

Reply to
dennis

I had to rectify a cowboy's work on a new boiler. The tosser had connected the Qualpex right onto the boiler. It had lasted three months or so, which surprised me.

Reply to
Grimly Curmudgeon

I think that is the recommendations of the plastic pipe makers as well.

Reply to
chris French

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