Fresh water tank - what tubing to use?? Confused! (1 Viewer)

[johnandi]

I'm replacing the 'Outlet cap ' on the top of the fresh water tank (Hymer B654) and also the tubing between the cap and the submersible pump (this follows a not so successful replacement pump and tubing fitting last year where the tube now keeps separating from the old outlet cap - hence why I'm replacing the cap!).
I'm finding it difficult finding a tube with the right internal and external diameters (and it's got to be 'foodsafe?' as it's constantly underwater in the tank). Anyone done a similar replacement please?
I'm also having a problem figuring out how the screw tops supplied with the pump and Outlet cap are supposed to work? They don't appear to be tapered inside so how can they tighten on a tube??
Finally, the original tube was rigid (and used push-on Reich fittings) and I think a rigid pipe would be better as the pump wouldn't then slosh about at the bottom of the tank - just a thought!
Any help would be appreciated,
Thanks,
Confused!

 

[mitzimad]

looking at the picture i think the "olive" to make a seal is built into the connection and is broken of on one of the white connector and partially on the pump when tightened the end squeezes onto the tubing within ive no knowledge of hymers but i am a plumber and have used similar fittings on 6mm fridge water supplies

 

[johnandi]

looking at the picture i think the "olive" to make a seal is built into the connection and is broken of on one of the white connector and partially on the pump when tightened the end squeezes onto the tubing within ive no knowledge of hymers but i am a plumber and have used similar fittings on 6mm fridge water supplies

Thanks Mitzimad. The bottom fitting on the Outlet cap is just an air vent from the tank and therefore has no connection on the inside.
You're right, the top of the pump does have a bit missing (broken off my me!) but this stub is (I think?) for 9mm I/D pipe whereas the screw fittings (I think?) fix onto the larger, second stub which is about 11mm/ 3/8" diameter. The I/D of the screw caps are about 16mm.
Getting a 11mm I/D and 16mm O/D tube seems difficult. I think it was PappaJohn last year who said he'd had a similar problem.

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[JeanLuc]

It is difficult to get exactly the correct size of tubing. I replaced mine a few years ago when I fitted a new pump. I got some braided clear hose and had to pack it a bit with ptfe tape under the collet to get a good grip. It all works well and I will have a dig around in my files tomorrow to see if I can find details of the hose.

 

[johnandi]

It is difficult to get exactly the correct size of tubing. I replaced mine a few years ago when I fitted a new pump. I got some braided clear hose and had to pack it a bit with ptfe tape under the collet to get a good grip. It all works well and I will have a dig around in my files tomorrow to see if I can find details of the hose.

Thanks Jeanluc. Actually a search around the garage just now has revealed this tube. It's seems an old 3/8" I/D and 5/8" O/D and actually does the job brilliantly. Fits snug on over the larger stub and the 'collet' tightens over the tubing. I need a longer piece so think I just need to find a supplier.
Another problem I had with my attempt last year was the clear tube I'd used inside the tank became covered in black mound. This tube is blue/opaque so shouldn't suffer the same problem (maybe?).

 

[JeanLuc]

I have been looking through old invoices and I'm pretty sure I got the hose from this supplier
http://www.sealsdirect.co.uk/shopping.asp?intDepartmentId=6#48

and it was 10mm i/d, 16mm o/d like this
http://www.sealsdirect.co.uk/pdf/NBH105aDS.pdf

As I said above, I still packed the screw compression collars with a few turns of PTFE. Over time the tube is almost certain to get a bit discoloured, but if you buy a metre you will have ample for future use.

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[scotjimland]

The discharge pipe on mine had plenty of slack so I cut a piece from that to replace the short piece on the pump.

 

[Lenny HB]

The tubing 10mm id, I bought some a few years ago from CAK Tanks, other place to look is German eBay as said not a common size in the UK.

 

[Popeye]

I have recently installed a water filter and found THIS site invaluable, particularly with Metric to Imperial reducers.

The items arrived by return post, outstanding people to deal with.

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[johnandi]

Many thanks to you all for all the help and advice. I'll investigate the websites mentioned today and hopefully will come up with a solution. If I can find imperial pipe I'll post the supplier on here for future reference. I'll also contact sealsdirect, CAK and John Guest. I'll also have a look at the discharge pipe just in case I can nip a piece of that.
Cheers

 

[johnandi]

Many thanks to you all for all the help and advice. I'll investigate the websites mentioned today and hopefully will come up with a solution. If I can find imperial pipe I'll post the supplier on here for future reference. I'll also contact sealsdirect, CAK and John Guest. I'll also have a look at the discharge pipe just in case I can nip a piece of that.
Cheers

For information is case anyone has similar problem I found this on Ebay. Slightly smaller OD than 5/8 but collets nip up and seems to have done the job:
http://www.ebay.co.uk/itm/251402026827

Hope it helps someone.