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barnaby · Joined: 18 Jun 2004 Posts: 3 Location: Up North

I need some help with a pressure issue. It's for my brother who's living in France in a static caravan next to his fishing lake. Problem is that he has no mains water at the moment and the scenario is thus:

He has the static caravan, which is on his land next to a fresh water fishing lake. He's installed a 100-litre tank 7m up a tree. To complete the picture he has a submerged pump and filter system that he uses to fill the tank when needed. On the other end he has a 25m 25mm pipe running to the inlet on the static caravan.

Generally the boiler, which is a Bosch, works fine when you're calling for hot and cold water from the taps but when they try to use the shower it cuts out within a minute (i.e. as soon as the hot gets up to temperature).

The boiler has what appears to be a restrictor valve, which increases or decreases the flow and the opposite with the temperature. Other than that he says that all stop cocks, etc are open and he's tried turning the heat down on the boiler and just running the shower off the hot but still it cut's out.

The boiler says that the min inlet pressure is 0.15 bar and the max is 12 bar. I know that 10 litres of water is 200lbs in weight but so far as converting that to pressure I wouldn't know where to start.

Do you think he needs to raise the pressure with a pump just for when they're taking a shower? Any advice you can give would be great as he's really struggling with the French plumbers, as they basically don't want to know.

Cheers,
Barnaby

thescruff · Moderator Joined: 03 May 2003 Posts: 4751 Location: Bath

7m head will give .7 of a bar at the boiler, so assuming the boiler is hanging on the wall the static head will be 5m ish or 0,5 bar.

I would say that maybe he has the wrong shower mixer for a combi.

Low presure non-thermostatic types would be better.

scruff

barnaby · Joined: 18 Jun 2004 Posts: 3 Location: Up North

Cheers Scruff,

I'll get him to investigate. The only thing is that the static caravan has come from a camp site in Paris, where it has been used for holidaymakers for the last 4 years. I would have thought that the shower with it's current set up would have been working before now. Is it anything to do with the low-ish pressure that he has? Could you explain a wee bit more the shower mixer thing so I can be better armed when explaining to him.

Many thanks,
Barnaby

barnaby · Joined: 18 Jun 2004 Posts: 3 Location: Up North

I probably didn't word my last post so well. Quite an open question requiring too much typing. I'll re-phrase:-

Would there be any advantage by running a pump on the inlet pipe whilst showering, to raise the system pressure? As there is a good head of water and no risk of pump cavitation, could this solve the problem and avoid changing the shower mixer?

Regards,
Barnaby

thescruff · Moderator Joined: 03 May 2003 Posts: 4751 Location: Bath

You could try fitting a pump from the tank supply to the shower.

Away all week so answers can be slow at times.

scruff