Imperial Sized Hep2o Fittings?

Freeloader

Freeloader

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My American-built Legend 37 is fitted with Hep2O-style semi-rigid pipework and fittings for the fresh water system. However, it must be manufactured to imperial sizing, as none of the metric fittings that I have tried will fit. Can anyone advise where I may be able to source suitable parts and fittings in the UK?
 
Freeloader said:
My American-built Legend 37 is fitted with Hep2O-style semi-rigid pipework and fittings for the fresh water system. However, it must be manufactured to imperial sizing, as none of the metric fittings that I have tried will fit. Can anyone advise where I may be able to source suitable parts and fittings in the UK?
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I have never seen imperial size Hep2o and I dealt in them for 25 years! Suppose America could have used some but unlikely.
Why do you think they are imperial and what size are they?
The difference between 15mm and 1/2" is minimal, 22mm is a bit bigger than 3/4" but in both cases brass compression fittings should fit, use 3/4" olives in 22mm fittings.
28mm and 1" similarly, always use the correct size olives and inserts in the tube if its plastic.
 
It's clearly not genuine Hep2O but an imperial-sized alternative, so Hep2O fittings will not work. The pipework is the usual 1/2" internal diameter but the crucial external diameter is slightly different. From memory, it is approximately 19mm external diameter?
 
Freeloader said:
It's clearly not genuine Hep2O but an imperial-sized alternative, so Hep2O fittings will not work. The pipework is the usual 1/2" internal diameter but the crucial external diameter is slightly different. From memory, it is approximately 19mm external diameter?
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This sounds like black alkathene or blue MDPE thick wall pipes. Alkathene used imperial compression fittings and push fit, meant for burying.
19mm is 3/4".
Search MDPE fittings.
 
Freeloader said:
My American-built Legend 37 is fitted with Hep2O-style semi-rigid pipework and fittings for the fresh water system. However, it must be manufactured to imperial sizing, as none of the metric fittings that I have tried will fit. Can anyone advise where I may be able to source suitable parts and fittings in the UK?
Click to expand...

I'd try contacting John Guest, the company which makes Speedfit push-fit plumbing. John Guest is an international company, and their American plumbing catalogue is full of fittings for imperial-size pipes. You can download a catalogue here - https://www.johnguest.com/wp-content/uploads/2014/07/USA-Plmbing-March-2015.pdf - it's not recent but will give you an idea and I doubt that the product range has changed much.

If you can find what you want in the American catalogue, ask John Guest UK if they can get the bits for you. Their contact numbers are here - Contact Us | John Guest Speedfit I'd suggest phoning them initially, rather than filling in a contact form.
 
Unfortunately, the battery was flat in my electronic gauge, so I had to just read the scale. However, it would appear that the outside diameter of the pipework is approximately 16.5mm, so way to large for the usual UK 15mm push-fit fittings.

I am trying to fit an expansion tank inline with my calorifier, so I will need some additional fittings and pipework. Either I need just imperial parts (I will look into the suggested Speedfit fittings) or an adapter to connect my 16.5mm pipe to metric 15mm pipe. All the fittings that I have found will take one or the other standard but not convert the two. Any suggestions?
 
I would look at getting a short piece of plastic machined to fit each connector, then you would be at a standard size for over here and not have the problem in the future
 
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