Push fit connectors for central heating?

[Matthew]

Hi All,

Does anybody have any experience of using the push fit plastic connectors on central heating systems? How reliable and robust are they? I was thinking of adding antother radiator upstairs and just wondered how durable these fittings are. It would be a plastic section tee'ed into a copper run. A lot of places seem to sell it now (in Wickes at the weekend) and I like the idea of convenience. However am not sure about these fittings (but then I dont know how they work) in that they only seem to seat on an O ring. Presumably it must be reliable. The new build houses near us seem to have had plastic almost throughout, you could see it from the pavement during the build.

As an aside, as I mentioned last week I have a leak under a concrete floor and was going to replace that section with new copper. Would plastic also be suitable here?

Thanks for any advice, Matthew

[Grunff]

Yes, many people do.

They're fine.

That would be fine, as long as you have spare heating capacity. You may well need to re-balance.

They're fine.

If it's buried in concrete, plastic would be better.

[Christian McArdle]

They're fine. I tend to use compression fittings instead, though, as I'm a cheapskate and they're much cheaper.

I wouldn't dream of burying copper in concrete these days. Plastic is far superior. These days, you should either be using pipe within a pipe in a concrete floor, or leaving the pipe channel intact and boarding over for access.

Christian.

[daddyfreddy]

I've always used JG Speedfit fittings and haven't had any problems. Copper is fine with me but plastic pipe hidden away can save a lot of time with awkward runs.

[Matthew]

How do the plastic fittings fair on mains pressure water, say 5 bar, hot and cold?

Thanks, Matthew

[Grunff]

They're fine.

[mcbrien410]

'O' rings are just fine. In the oil industry they are used downhole at

15,000psi and at 175degC.

Just make sure there are NO scratches in the mating area where the 'O' ring makes the seal.

Also don't forget to lock them.

Chris.

[Roger Mills (aka Set Square)]

Plastic pipe and push-fit fittings are fine for central heating systems - and for domestic hot and cold water distribution - with a couple of exceptions. You can't use plastic pipe within a metre or so of a boiler. Also, I wouldn't use it in situations where is needs to support something, such as a pump or zone valve.

For central heating, you *must* use barrier pipe - which prevents oxygen molecules from permeating through the walls. AIUI, Hep2O is made in barrier and non-barrier versions, so you need the right type. I think JG Speedfit pipe is *all* barrier.

You can mix and match copper and plastic pipe - and fittings. For example, you can use compression fitting on plastic pipe - provided you use pipe inserts in the ends - or you can use push-fit fittings on copper pipe.

Push-fit fittings use a star-lock washer which digs into the pipe and grips it, and an O-ring to provide a seal. They are all good for pressures of up to 9 or 10 bar. Many types can be de-mounted. I like the variety of JG Speedfit fittings which have a bit which rotates to lock them, stopping them from being accidentally demounted. But they are a bit bulky. For neatness, where the fitting shows - particularly if using copper pipe - I use copper push-fit fittings which are much slimmer.

[Andy Hall]

They work very well.

One general point is that using the proper cutting tool on the pipe, as specified by all the manufacturers is an instruction to be followed. They are not expensive.

[Matthew]

Thanks for all the info. It looks like certain 'little plumbing' jobs that I have put off till later will be carried out sooner than I thought!

Where is the cheapest place to buy the plastic fittings from?

Thanks, Matthew

[Andy Hall]

Any of the plumbing or heating merchants or on line if you prefer at

[Dave Plowman (News)]

If cost is a factor copper with end feed solder fittings is even cheaper. ;-)

[Antony]

The cheapest are the usual crowd:

plus, you can try eBay. Do a search on this term (speedfit, speed fit, johnguest, john guest) and you'll get a long list of items for sale. It's usually the cheapest way to get coils of pipe and bags of fittings, but not so good if you want a specific single fitting. I've used this route with some success.

If you only want one or two things, it's better to go to B&Q Warehouse or Wickes, but the fittings are about 2x the other sources.

You can also get pushfit radiator valves, if you want.

BTW, for short runs (less than 3m), I'd suggest getting the straight lengths of pipe rather than coiled. The coiled speedfit pipe doesn't like being straightened (especially the 22mm stuff).

Always remember to cut the pipe square and clean using the proper tool, and use the right insert for the plastic pipe and fitting (speedfit has two different inserts for pushfit and compression).

-Antony

[daddyfreddy]

I've used them on mains pressure pipe as well with no problems. Even used one on an outside tap with plastic pipe once - but that has to be painted because they're not UV safe. Admittedly, I've failed to get round to painting it. Must get that sorted!

The only things to watch for, particularly with the JG Speedfit or other stuff with the exposed release collar is that it isn't near a pipe clip or joist that could depress it. You can get circlips that you push into the gap or covers to prevent this.

Also, you've got to take more care with plastic pipe because you want to avoid having any nicks where the rubber seal will sit. I'm pretty meticulous and I've had no failures so I don't know how much you can get away with.

[Andy Evans]

Really? I found the proper tool didn't cut as well as a less expensive pair of secateurs.

Andy.

PLEASE remove spam_off to reply

[Andy Hall]

I don't know what you bought.

Certainly the blade needs to be sharp so that the pipe is cleanly sliced rather than crushed.

This Monument one is pretty good, having an anvil to steady the pipe square as well as a ratchet action

[Doctor Drivel]

Matt, it is not good at all and a waste of money. I have used one. You have to compress the blade and body of the cutters together, which can nick your hands, so the ratchet can catch the next notch. It also can leave a sharpish edge that may nick the O ring. I would rather us a hacksaw and finish off with a file or sharp Stanley knife to get the square clean edge than use that tool.

Best avoided.

[Andy Hall]

Either you had a dud one or you are cack handed.

Mine works fine.

You're not supposed to put your fingers in the way......

You are meant to have a clean square edge. If you do that and insert the tube according to the instructions, then nothing bad will happen.

Mmmm.... and it's a matter of record as to what happened to you when you tried that.

[Doctor Drivel]

Matt, it was not dud, pretty new, and a poor design. The ratchet steps are too far apart.

You have to hold the blade and body together for the fratchet to catch. Your fingers can get nicked.

Matt, that is so, but it doesn't always give one.

Nothing does happen unless you hold the two together as you squeeze the handles together

I have done that regularly and always had a square clean edge as I am a craftsman. These cutters are supposed to make matters quicker, but don't deliver on usability and the result, which is not good enough as I had to use a fine file to take away the nicks. A waste of time. Monument rebaged the tool and obviously never tested it out.

[Dave Plowman (News)]

See other threads about the water shortage...