Nightmare using compression fittings on plastic heating pipes

[DIYedboy]

I've been doing DIY plumbing for 30yrs.............I'm no expert but I can do it.

I wanted to run plastic pipes (with pipe insulation too) under the floorboards because it can withstand freezing temps better and for the first time I'm using brass compression fittings with inserts in the pipes because a brass fitting will not leak but that O ring on a plastic pushfit will finally give up in about 40yrs time.

I've run the pipes, had the heating working for the last 3 days............BUT................every morning most of the joints are leaking, I tighten the fitting more and all is good for the day. The next morning the heating won't work cos the pressure has dropped due to all the overnight leaks!!!!!!!

3 days this has happened, I'm gonna have to rip out the plastic n use copper. Has anyone else had this? my inserts are plastic but suitable for compressions

 

[slippyr4]

If you've been doing plumbing for 30 years already, will you be around in 40 years time when you suspect the o-rings in push fit will give up? (Some push-fit ranges are guaranteed for 50 years)

I'm not sure that plastic is any more frost resistant, other than that it insulates a bit better. At the end of the day, if the water freezes in a pipe, it'll fail, plastic or copper.

Anyway, I suspect that you have overtightened the fittings.

 

[Burnerman]

Are you using a stainless steel insert, or a plastic one?
John

 

[Jackrae]

Are you using brass olives or copper ones. Copper being softer than brass will get a better seal on the soft plastic wall.
40 years guarantee on an approved fitting sounds a lot better than failed compression joints.

 

[OvertonPlumber]

It's so simple to do leak free compression on plastic. Firstly tighten it up just past tight. Then undo it and pack the olive with a ton of ptfe tape then do up again voila.!

 

[DIYedboy]

How can anyone realistically give a 50 year guarantee on something that hasn't been around that long being that it has to undergo heat/ cold expansion cycles and under chemical attack from corrosion inhibitor? and even better, how many people would still have their receipt to actually be able to claim on that guarantee !

Mr Benchmark............you're a genius!............what a brilliant tip, who would know to do that!.............I'm now too 'frightened' to do that bearing in mind I have tightened 'the nuts' out of those fittings, so wonderful never let a man down copper pipe is going in

 

[Dan Robinson]

I dread to imagine the horror show that is being created by the OP . Can what're some pictures ?

 

[slippyr4]

50 years is estimated based on testin of repeated hot cold hot cold cycles and known data about how long it takes for the rubbers to perish.

How long will your PTFE over olive seal for?

 

[DIYedboy]

Copper pipes in, no leaks, I shall never stray from the path again!

 

[SandyLyon]

How can anyone realistically give a 50 year guarantee on something that hasn't been around that long being that it has to undergo heat/ cold expansion cycles and under chemical attack from corrosion inhibitor? and even better, how many people would still have their receipt to actually be able to claim on that guarantee !

You obviously know very little about how things work in the world of R & D and manufacturing.

Looking at the Hep2o system (50 year warranty)

a) It's actually been around for approx 40 years (firstly as Acorn then Hep2o)

b) As slippyr4 says above, product is on test 24/7, 365 day a year constantly cycling extremes of temperature and pressure. 50 years normal use can be replicated in much less time (all to relevant standards, British, European, Asian etc)

c) you wouldn't need your receipt as part of the BS / ISO standards requires all pipes and fittings to be stamped with data. The pipe is laser printed every metre with information of date and time of manufacture, what line it was extruded on as well as other coded information. Likewise the fittings are UV laser printed with similar information.

Nothing wrong with using compression fittings with plastic pipe as long as you follow the basics, use pipe insert, copper olives, don't over tighten, PTFE tape if needed (no jointing paste).

Or you could have used Hep2o pipe and fittings and got a 50 year warranty.

 

[DIYedboy]

of course I don't Sandy....................I'm just a normal bloke that don't stay in all the time looking up how products are tested!!

Ignoring your comments (which have arrived waaay too late to actually be helpful!!) it's interesting that another rad I have temporarily plumbed in with grey plastic pipe n compressions seals first time every time, the white stuff (with brass olives n plastic inserts) from Screwfix gave me all the problems.......................no-one wants problems!