shower pumps

[seany1]

If I install a pump in my hot press fed from tank in attic but which I can only connect to hot and cold supply to whole house rather than shower only,which I cant access,will this lead to prblems with washing machine/bath/sinks/tiolet cisterns?

[stanleyman]

What I think you are saying is can you connect a pump to the hot and cold supplies rather than just the shower that you cannot access, presumably because it runs off the existing supplies. If so, then the pump will just run whenever water is used beyond the pump.

Assuming you have a cold supply from the loft tank feeding at least the bath/shower to link into and the hot supply from the cylinder to link into then there shouldn't be any problem apart from the pump may draw air down the hot vent pipe. You could fit a non-return valve (not a sprung check valve) in the cylinder vent pipe to allow air up but prevent it coming down if it happens.

[qapmoc]

If I have got the meaning of what you want to do this means you will be pressurizing the hot water tank which is NOT designed to withstand more than normal atmospheric pressure and would probably split if you pressure it from a pump.

[stanleyman]

If a pump is fitted in the cylinder supply then it would just pump water back up the vent pipe to the loft tank losing most of the pressure advantage but quapmoc is right, a vented cylinder cannot withstand high pressures. You would need an expensive unvented cylinder fitted with safety devices to be able to pressurize the whole system and then you can use the mains supply instead of a pump.

[seany1]

The pump will be connected to the supply from the hot cylinder on the inlet side of the pump and the outlet or supply side of pump will be connected to the hot supply to shower/bath/sink/washing machine.The cold inlet to pump will connect to cold supply to house from attic tank,not to hot cylinder and pump outlet/supply will connnect to cold supply to shower/sink/bath etc.in this way it will not pressurise the hot cylinder.

[stanleyman]

Yes ok that is the same as my first.