Installing power shower

[grahamw01]

I've read here
http://www.plumbworld.co.uk/191-0000

That power showers are not compatible with mains cold water. Can anyone tell me why this is please. It also says that some require an electrical connection. Can anyone explain why some do and some dont. I assume the electrical supply is to drive the pump.

Any help would be brilliant, thanks

Graham

 

[steboy]

It just means you must feed the two pump inputs from the hot and cold reservoir tanks. It won't work connected either to the cold mains supply or if your water is heated instantly by the boiler. An electrical supply does indeed power the pump.
ste

 

[bathjobby]

That power showers are not compatible with mains cold water. Can anyone tell me why this is please.

The answer is in what you have already read i.e.

A power shower is simply a mixer shower with a built-in pump

Forget the pump for a moment; you have 0.1 bar of pressure from your hot water tank and you have around 3.0 bar of pressure from your cold mains. Now connect the two together and what do you think will happen ? Yes, you will get 'some' water out of the shower head but the cold 3.0 bar is going to push straight into your hot water tank = lots of mess, overflows everywhere. Putting the pump into the scenario doesn't change that much...

 

[grahamw01]

Would something like this help

http://www.plumbworld.co.uk/344-230

 

[omega015]

i am wanting to do the same with the pressure equalizing valve, will that solve the pressure from mains problem? or would you need to install none return flow valves aswell?

 

[ChrisR]

Equalising valves don't solve the problem very well at all - outside their envelope. Take pipes from the HW cylinder, and from the CW cistern in the loft, to a mixer. Put a pump in if you want , or a Power SHower which is a combination of the two.

Or you could use a venturi type shower which uses mains cold to suck hot out of the pipe - but not as well as a pump.

 

[omega015]

i have tested the pressure and have mains cold @ 3bar and hot from cylinder @ 0.8/1.0 bar. i already have a thermostatic power shower from a friend and really would like to use as wiring an electric shower would be a lot of hassle. i dont have a cold water tank.

are these my options?

no shower - not really the point
eletric shower - really would be a hassle to install
already own power shower - purchase a PE valve http://www.plumbingpages.com/featurepages/Greens.cfm and use non flow return check valves http://www.screwfix.com/app/sfd/cat/pro.jsp?cId=100121&ts=11431&id=19860#
other? - please advise on any recommendations

 

[grahamw01]

Does your power shower require an electric connection. How are you finding the equalising valve

 

[omega015]

yes the shower needs electrical connection but only needs a 3amp spur so i can route from nearest point. and havent purchased the PE-Valve yet

 

[grahamw01]

My cold water is off the mains and the base of my cold water tank is about 1 meter max from the shower head. What can I do?????

 

[omega015]

do you mean base of your hot tank?

 

[grahamw01]

No, the base of my hot water tank is on my bathroom floor. The base of my cold water tank is about 6 inches higher than my shower head. I measured roughtly last night

 

[omega015]

oh ok, it was just u said your cold is off the mains and then said cold tank. what about using a pump from the cold tank? i am only guessing as i am new to this and want to install my shower too