1995 Hymer water returning. Even with new pump

[Dee101]

Hi, I have a 1995 Hymer B654. A couple of weeks ago the water started glugging, that is to say it was returning through the pump back into the tank, just as soon as the taps were turned off. I changed the pump (and I’ve tested it, it works perfectly, as indeed did the previous pump). It is very frustrating. The micro switches seem to work correctly. Is there a non return valve (that may have failed) hidden away in some dark and unknown location, or indeed not? Because if so, it is not self evident. I do also understand that this “older” system is pressurised.
Any help would be much appreciated. I have looked online and also here at Motorhomefun, on the relevant “water” section, but have found nothing that comes up with a satisfactory remedy.
Kind Regards
Dee

 

[GeoffnDee]

If your water pump is the submersible type and there is not a non return valve near/on the water pump an inline one may be in the water supply pipe near or at your hot water boiler.

 

[Figaro]

Sounds like a NRV fault. As far as I know, they're usually on the submersible pump, did the new pump come with one ? You could try fitting another in line one

 

[nicholsong]

Most Reiche submersible pumps have a NRV attached to the pump.

Whale pumps do not have one and need a separate NRV.

What is your new pump?

 

[pappajohn]

With a submersed pump and microswitched taps your system is NOT pressurised.
Fit a non-return valve in the pipe close to the tank.
Not worth looking for the old valve as when you find it it will still need replacing, easier to fit a new one somewhere else.

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[Dee101]

I’m looking online. There seems to be 10mm and 12mm. But there’s no information about which one got a 1996 Hymer. Foes anyone know the correct (or likely correct) diameter? Snd can it be practically any make?
Dee

 

[pappajohn]

Water pipes are 12mm.
Any make .