John Guest ?

#1
I need to replace both hot & cold water pipes in my van & wondered if push fit John Guest pipe connections are secure & leak proof ?
- Also, would reducing the pipe diameter from 15 down to 12mm cause the pipe joints to blow due to pressure from the pump ?
 

Squiffy

Full Member
#2
I need to replace both hot & cold water pipes in my van & wondered if push fit John Guest pipe connections are secure & leak proof ?
- Also, would reducing the pipe diameter from 15 down to 12mm cause the pipe joints to blow due to pressure from the pump ?

I've always used 12mm semiflex pipe and john Guest push fits, the only time I had a leak was because I hadn't pushed the pipe in fully into one of the cold water joints. They are a great invention and speed up plumbing no end.
As for the pressure they will take far more pressure than standard surflow trail kings can produce. Phil
 


#3
I went for 10mm Speedfit plumbing throughout, my reason being that, most especially in the hot pipe run there is far less wasted water when waiting for the hot water to arrive at the tap, it also resulted in me being able to conceal them far more easily. When fitting the pipe the No.1 thing to remember is to always fit the pipe inserts before pushing the pipes into the click lock joints.
Like my old mate Squiffy, I also have a Surflow pump and have never experienced any problems with water leaks, that is after I finally bit the bullet and bought some proper tap connectors!

Good luck

Phil
 


Edina

Administrator
#4
I've used lots of push fits without any problems. As Phil said you must use inserts and it's worth making a pencil mark on the pipe before you push it into the fitting, so you know it has gone fully in. Also worth buying a pair of shears to cut the pipe; they give a clean cut without the need to debur like you need to with sawing.
 


Steven

Full Member
#5
I used 15 mm speedfit in my van, no leaks and it’s easy to change things.Just remember to fit the inserts though, as that’s when they leak!

Stephen.
 


Steven

Full Member
#6
The silicon spray is handy too for getting the inserts in

Stephen.
 


#7
We used JG throughout our build it just like coupling an air line we’ve also to date had no leaks! To cut a square end we used a cooper pipe cutter just tighten it gently. To get the inserts in dip the end in a jug of hot water or your cuppa if you have one to hand. (Yorkshire Tea works best)!!
Take care all
Ken
 


#8
In researching, I'm "struggling" to find converters from 12mm push fit to the 1/2" flexible pipe at a reasonable cost? The tank fittings, pump fittings, and boiler fittings are all expected to be 1/2" push and jubilee-clip type.

Also - I'm planning on fitting a thermostatic shower (small) - but that's going to be 15mm copper into a 90' elbow, soldered or push, but how to get that back to 12mm? Not seen 12-15 elbow (ideally) or 12-15 straight?
 
#9
In researching, I'm "struggling"
I experienced exactly the same problem, but then I popped into my local Plumb Centre (now known as Wolseley) and told them about my problems...... I also took in the various items that I was fitting into the system........... and between the 3 blokes behind the counter and about a dozen plumbers who were in there having an early morning "crack" I got it all sorted! I also found that the prices charged there were very similar to those being asked in either Toolstation or Screwfix.

Phil
 
#10
Ok - many thanks for all your advice - next step is to source the pipe & fittings.
 
#13
sounds like you are sorted :)
I used 12mm flexible pipe I bought from a local company - "Border Leisure" in Jedburgh (they don't have a website) - £1/Metre
From a local Agricultural suppliers I bought adapters for the fitting size needed (1/2" for some fittings, 20mm for the tap fittings) to 12mm hose barb fittings - no need for inserts, just push on and secure with jubilee clips.
I couldn't believe their prices for this stuff (https://www.agriparts.co.uk/) - like a throwback to the 80's!
 

Darcar

Full Member
#14
I used 15mm John Guest, throughout our build, the 15mm beeing the most common size makes it available everywhere and in all the fittings.
It’s also the cheapest size. Never had a leak and very easy to use.
Darren.
 

Squiffy

Full Member
#15
I used 15mm John Guest, throughout our build, the 15mm beeing the most common size makes it available everywhere and in all the fittings.
It’s also the cheapest size. Never had a leak and very easy to use.
Darren.

The only trouble with 15mm Darren in my view is its far more difficult to get a tight bend and although its officially only 3mm different it uses considerably more space. Phil
 

Darcar

Full Member
#16
The only trouble with 15mm Darren in my view is its far more difficult to get a tight bend and although its officially only 3mm different it uses considerably more space. Phil
Yeah I must agree that it doesn’t bend very easily. 😀
 

Steven

Full Member
#17
I find that the 90* beds are quite large,otherwise is great stuff to use

Stephen.
 
#18
Did any of you think of using truck airline hose for water,just a thought.
 
#19
Did any of you think of using truck airline hose for water,just a thought.
Would it be safe for potable water? Many pipe materials can taint the water, including standard garden hose. I wouldn't be sure of using air hose for this reason.
 


Misterg

Full Member
#20
Did any of you think of using truck airline hose for water,
The solid red and blue 12mm plastic pipe widely sold for caravan / campervan water seems to be the same stuff (nylon?) as industrial air hose.
 


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