shower pump in loft problem advice required

[Gary Holt]

I have just moved into a house with a mira 88 shower which is connect to a mira PPT3 shower pump. The problem is that the pump starts up (and keeps going) as a result other taps being used (only sometimes not allows), it can only be stopped via the hot bath or basin taps up stairs in the bathroom !

Having looked at your installation instructions it appears that the installation was incorrect. As the PPT3 is located above the shower in the loft, its cold feed is directly from the cold water tank about 30cm above the pump and the hot feed is from the hot water tank located in the bath room. There is not surrey/essex flange fitted and the output from the hot water tank is taken about 30cm above the top of the hot tank. Therefore I presume the other taps are causing the water to be pulled back down the hot water feed to the pump.

When I run the bath/basin taps as small amount of air comes out with the water !

So not being an expert but having investigated this my solutions appear as follows:

1.Fit a pull cord switch to the pump in the bathroom, to enabling me to turn the pump off when not in use. Does this cause a problem ? Also enabling me to use the shower without the pump ? 2.Fit a surrey flange to the top of my tank therefore the feed for the pump will be lower , therefore the water might not be able to be pulled from the hot water pump feed.

3.Move the pump into the airing cupboard, lots of work !!!!!

My first idea is to do 1 and then may be 2 Any ideas welcome.

[BillR]

This is the one to try. After all thats what most shower manufacturers recommend. The height of the Surrey flange is irrelevant. Its the height of the tank in loft feeding the hw cylinder that matters.

The pump won't work very well in the loft anyway unless it designed for this. I believe they have to be specified for "negative head". Is the PPT3?

[IMM]

It is best to have the pump below the water level in the cold water tank. There are some timer pull cords around. You pull the cord and its start up the pump, the flow switches on the pump detect flow and keep it going, the time times out and the flow switches keep it going. You turn off the mixer valve and the pump stops as there is no flow. Foolproof.

[IMM]

Fit the Surrey flange. Make sure the cold feed from the cold tank is not teed off a pipe. It must go directly onto the side of the tank having its own dedicated supply pipe.

This should cure it, as long as the pump and its supply pipes are "below" the water line of the cold tank at all times.