Some pictures for reference - https://imgur.com/a/n3ThLIL I've been trying to work out why we have terrible water pressure from our shower. This is on the first floor of our house and is the only shower in the property. We have a three story house, with a bedroom in the loft space. There is an airing cupboard in this room which contains a hot water tank. In the small loft space left above this room sits a water tank and a F&E tank for the central heating. At the top of the hot water tank is what appears to be a surrey valve. The bottom outlet of the surrey valve has a straight pipe which eventually curves up and out of the ceiling of the airing cupboard (with an isolating valve with blue handle just before it leaves the cupboard). The top outlet of the surrey valve has a straight pipe which then comes to a T junction, from the top of the T junction a pipe goes up and out of the ceiling of the airing cupboard. From the bottom of the T junction a pipe runs down and into the floor (with an isolation valve with a red handle halfway along it). I'm assuming that the top outlet of the surrey valve is supplying the hot water to all the taps in the house and at the T junction the pipe running up is the vent pipe up to the water tank in the loft, and then down to the taps. Which I guess means the bottom outlet of the surrey valve is feeding our shower. Tonight when I get home I'm going to try turning off each isolation valve and see what happens with the taps and shower. So coming finally to my question for any good DIY'ers or plumbers - Is it usual for a surrey valve to be installed if there is NO shower pump installed? From my research a surrey valve is only installed when you need to feed a shower pump, but we have NO shower pumps installed If the bottom outlet of the surrey valve is supplying our shower, could I add a pump to this pipe to fix the pressure issue?