various plastic pipe questions

[sparksburnout]

I have some general questions about plastic pipe systems, as I have not used them before, and am a little confused:

1. Are all the various brands interchangeable? For example Flowplast, "JG" Wickes own brand etc, or are we still in the dark ages of the various brands being slightly different?
2. I need to Tee a plastic pipe into an existing copper one. Is it really satisfactory to use a plastic speedfit Tee to connect to copper, as it says on the fitting instructions?
3. I am taking the plastic pipe into a shower (Triton) and they say that it is not acceptable to use push fit connections onto the inlet pipe. Can't see what the difference is myself, anyone any thoughts on this? I have tried to get a conventional compression to push fit connector but can't seem to find one, can you use a conventional compression fitting with plastic piping?
4. If burying the pipe in a brick wall, is it preferable to house it in trunking to allow movement etc (its just a cold feed) or ok to just render/plaster over it?

 

[sparksburnout]

Ah! Just answered one of my own questions i think.....do you use the inserts to allow plastic pipe to be connected into conventional compression fittings?

 

[Ermintrude]

Plastic on shower is because of thermal stress. Ur not supposed to use plastic within 1m of boiler. U can mix fittings but use insert for the pipe not for the fitting. Plastic fine on copper as long as it's clean . (Bright - wire wool or pan scrubber . To concert to copper just use a normal plastic elbow or straight.

If your fitting a shower I hope for safety's sake your electrical is better than your plumbing!

 

[sparksburnout]

Plastic on shower is because of thermal stress. Ur not supposed to use plastic within 1m of boiler. U can mix fittings but use insert for the pipe not for the fitting. Plastic fine on copper as long as it's clean . (Bright - wire wool or pan scrubber . To concert to copper just use a normal plastic elbow or straight.

If your fitting a shower I hope for safety's sake your electrical is better than your plumbing!

Thanks for the (almost) sarcasm free reply. Yes, I am a fully qualified spark, just not up with this new plastic plumbing stuff that's all. Now, I understand why you have to keep the first meter copper if you are taking a feed from a boiler, but does this apply to an electric shower? Is it classed as a boiler? Surely the heat is going away from the entry pipe not into it, the particular shower has a 30 second overrun so the unit cools after it is switched off, so I would of thought the heat transfer is going to be minimal. Would you recommend just using a conventional compression fitting off the shower stub and then onto the plastic, or have a meter of copper before the shower?? What do you recommend regarding putting the pipe in trunking/capping before making good?

 

[Dotty]

Inserts in every plastic end, dont mix and match pipe and fittings. Pipe up exactly as manufacturers instructions or they'll wriggle out of any warranty call back.

No buried joints, all are to be accessible. trunk or tape your copper pipe, just make sure it's clipped.

 

[sparksburnout]

So you need an insert in every plastic end?? I have noticed from other threads that these are for strengthening the pipe when going into a conventional compression fitting? Seems like there is a lot of conflicting views on here! The manufacturers do not mention anything about using copper for a meter before the shower, just that push fit connections are not recommended, whatever that means exactly. Also, if the shower is going onto a brick internal wall and the customer does not want pipework on show how the hell do you not have buried joints??? There is going to be at least an elbow from the entry to the shower. Would taking this into a large diameter hole so that the joint can be inspected from the shower side satisfy the requirement?

 

[SimonG]

Theres no conflicting views as far as plastic goes. Follow the instructions, use inserts, pressure test and no problems. The shower manufacturer has stipulated that a push fit connection is not suitable so use a compression connector onto the shower.

Far easier to use copper. Less to hack out, just wrap the copper to protect it in the wall.

 

[snowhead]

The stub pipe for the shower connection is hard plastic, I suspect push-fit may not grip as well as it does on softer plastic used on pipes.
Copper olive will grip.

 

[Matt06]

Use copper its far superior to plastic solder the joints and wrap the pipe especially if its a solid wall , Solder the buried joints
Plastic can make horrible slapping noises if you don't clip/support it enough
Plastic push fit Blow apart If its mains pressure and can break earth continuity
And can be chewed Gliss gliss love Plastic

 

[sparksburnout]

blimey I've never seen such conflicting views you lot are worse than Sparky's! So, you can have buried joints then?? To be honest I can't see how you can avoid it myself. I thought the idea of using plastic was to make the job easier and also cheaper?? Are you saying that push-fit is no good for mains pressure???? Surely this is contrary to the manufacturers statements and also other members on here. And what i on earth is a Gliss gliss?????

 

[Ray Stafford]

1. Are all the various brands interchangeable? For example Flowplast, "JG" Wickes own brand etc, or are we still in the dark ages of the various brands being slightly different?

In theory all the 15mm pipes and fittings are interchangeable, but three points to recall.

• If you do mix and match pipe and fittings, and you get a leak, you have handed both manufacturers a get-out-of-jail-free card.
• Not all fittings are rated to high temperatures - for example, some valves are fine on domestic hot and cold supplies, but not on central heating.
• Always use an insert. I see from another of your posts that you have seen conflicting advice on this - they are wrong wrong wrong. The only variable is that JG have a different insert for compression fittings than for plastic fittings, but ALWAYS use an insert on plastic pushfit pipe.

2. I need to Tee a plastic pipe into an existing copper one. Is it really satisfactory to use a plastic speedfit Tee to connect to copper, as it says on the fitting instructions?

Yes its fine. It isn't elegant, and beware of the fact that you may break earth continuity, but from a functional point of view, it will work.

3. I am taking the plastic pipe into a shower (Triton) and they say that it is not acceptable to use push fit connections onto the inlet pipe. Can't see what the difference is myself, anyone any thoughts on this?

It doesn't matter what my thoughts are, or whether you can see the difference. The people who design and manufacture the unit are likely to know more about it than either of us, so follow the MIs.

I have tried to get a conventional compression to push fit connector but can't seem to find one, can you use a conventional compression fitting with plastic piping?

Yes its fine. Just remember to use an insert, and if its JG speedfit pipe, use there ordinary liner, not their superseal liner (the superseal has O rings).

4. If burying the pipe in a brick wall, is it preferable to house it in trunking to allow movement etc (its just a cold feed) or ok to just render/plaster over it?

I suppose it would be better to have trunking, but not usually practical. Just don't bury pushfit or compression fittings, and remember to wrap copper first.

 

[Dotty]

blimey I've never seen such conflicting views you lot are worse than Sparky's! So, you can have buried joints then?? To be honest I can't see how you can avoid it myself. I thought the idea of using plastic was to make the job easier and also cheaper?? Are you saying that push-fit is no good for mains pressure???? Surely this is contrary to the manufacturers statements and also other members on here. And what i on earth is a Gliss gliss?????

Soldered joints you can, demountable joints you can't. No confliction at all. And gliss would be mice. And rats.

 

[snowhead]

Also, if the shower is going onto a brick internal wall and the customer does not want pipework on show how the hell do you not have buried joints??? There is going to be at least an elbow from the entry to the shower. Would taking this into a large diameter hole so that the joint can be inspected from the shower side satisfy the requirement?

Treat soldered joints the same as maintenance free electrical joints, they don't need access for maintenance.
And compression fittings the same as screwed terminals, they do need access for possible maintenance.

The elbow to the shower connection is accessible through the shower cover.

Re mixing makes of pipe and fittings, that's the same as Consumer units should only have MCB's RCBO's of the same make as the C.U fitted. There's nothing technically wrong but in the event of an incident it could be proven not to comply with M.I's.

 

[sparksburnout]

OK Got it. I reckon that due to the fact it is a fairly short run of pipe and that it is going to be buried, then it would be better in copper, at least in the wall. just two more daft questions if I may:
1. Being as I don't have a plastic pipe cutter and I doubt it will be cost effective to buy one for a one-off job, is it possible to use a hacksaw and then a fine file to dress the plastic pipe before using it with a conventional fitting, just like traditionally with copper? I see why it is a no-no if you are using a Speedfit connector, but with compression? The reason I ask is that the pipe work not in the wall is under the bath and will be easier in plastic, I could just use conventional compression fittings.
2. Is there anything special to wrap the copper in before plastering over?

 

[SimonG]

I would just use copper. Easier to install, for me.

 

[sparksburnout]

Good analogy Snow. I think I will stick with the blow-lamp!!

 

[AWheating]

dont use a hacksaw. if you did buy a plasitc cutrer you can use it on plastic conduit on your future work.

the only real rule with interchanging plasitc pipe and fittings is using the pipe manufacturers insert, not the fittings. All the pipes have the same outisde dia. but the internal dia. can differ from one manufacturer to another.

compresion fittings are fine on plasitc if you use the pipe manufacturers insert and copper olives.

wrap any copper in lnsulation tape to stop any corrosion from anything that may come into contact with it. some pipe lagging would be a good idea to help stop noise, keep its temp/ stop any condensation.

use a compression elbow or coupler with a copper olive on the shower connection, dont use any paste.