Gary Holt wrote:
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.

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.

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.

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?