Pump on pressurised system for shower?

[Deansplit]

Is a pump to make a shower a power shower, allowed on mains pressurised unvented systems? I was told by a plumber to look into it as they're normally for gravity fed only?

Any help appreciated.

Thanks

 

[ChrisR]

The pressure on the inlet side of the pump would probably be too high for it.

Why do you think you need one?

 

[Deansplit]

Living in an area where I'm told it's only about 1.5bar - is there a site where you can find out pressures for areas? It's BT33. Also, I was going to get a unit which has body jets - I thought these naturally needed to be higher pressure?

 

[ServiceNumpty]

Get your plumber to give you the definitive figures on the pressure and flow rates, then check the marketplace.

 

[mysteryman]

You may not connect a pump to the mains. It has to go via a break tank.

 

[Deansplit]

I'm now informed that pressure here is 2 or 3bar but advised a 6 jet shower will struggle...?

 

[muggles]

Flow rate is also important, as is the dynamic pressure (measuring static pressure, IE the pressure with the taps off, is of almost no use at all). You can find your approximate flow rate by putting a bucket under a tap and seeing how much water flows into it in 60 seconds with the tap on full.

As has already been stated, you can't pump your present system, as it is illegal to pump water out of the mains. You would need to install a tank in the loft, and pump water both into your UV cylinder and the cold pipework to the shower, this slightly defeats the object of a UV cylinder but if the flow from it is really that poor then it sounds like it's been inadvisedly installed anyway, so this may be your only option

 

[Deansplit]

OK - one other Q - should the pipes to the shower (both hot and cold) be 15mm or 22mm? I know the inlets to the valves will probably be 15 (not bought one yet) but was told by a friend (does a fair bit of plumbing although not a plumber!) that 22 will project more water and have less chance of dropping when other taps are in use? Is that true, cos if so, there will be 2 basins which tee off from the feed, and everytime hot water at a basin is used to just wash hands etc, it'll take twice as long for the hot to get to the tap, plus twice as much water left to go cold...!

Thanks