Types of power shower
There are two types of power shower to look at. Firstly and probably the easiest is the all-in-one type. Secondly, there is a separate type which may have a single or double pump.
Power showers are pump assisted to provide uniform pressure and adequate flow. They are only suitable where the cold comes from a storage cistern and the hot from a hot water cylinder.
Hot and cold water supply
The cold water is fed from the cold water storage cistern and isolated by means of a gate valve near the cistern.
The hot water should be supplied via a special connection at the top of the cylinder, known as a Surrey flange. The feed from here is also isolated by means of a gate valve.
It is important to ensure that the cylinder has its own direct feed from the cold water storage cistern and that both the cylinder and cistern have sufficient capacity as recommended by the pump manufacturer.
Installing the shower pump
When mounting any type of pump, vibration and noise can be minimised by placing them on rubber blocks.
A neat way of doing this is to use rubber tap washers between the pump and the mounting surface at each of the fixing points. Alternatively, they are sometimes mounted on a cork base to absorb the vibration.
Try to fit the separate pump type at floor level near the hot water cylinder to ensure they do not run dry.
Installation of all-in-one type shower
Switch off the water supply to the cold water storage cistern and drain down. Drill through the sidewall of the cistern near the base and fit a tank connection piece. Run a short length of copper pipe from the tank and then fit a gate valve.
Continue the pipe run to the required position for connection to the shower unit.
Turn off the boiler and immersion heater, then switch off the cold water supply to the hot water cylinder and drain a small amount of water from it by opening the hot tap on a nearby basin or bath. Unscrew the vent pipe connection from the top of the cylinder and disconnect the vent from it. Take the new Surrey flange and wrap some PTFE tape around the thread to ensure a watertight connection before screwing it to the top of the cylinder and carefully tightening it. Remember the old advice – you can always tighten a little more, but overtightening may result in a lot more work. Reconnect the vent pipe to the top of the flange and connect a short run of copper pipe to its side outlet. Fit a gate valve to this before continuing the run to the required position at the shower unit.
By running the cold feed first, and labelling it at the shower end, it should be possible to get the hot and cold pipes the right way round on the unit! – it’s surprisingly the easy to forget which is which. After all, they look the same.
Before making the connections at the shower unit, flush the pipework to remove any debris which would otherwise damage the pump.
Unless you are experienced and are fully conversant with the current regulations, have the electrical work for the unit carried out by a qualified electrician.
Complete the assembly of the unit itself and restore the water supplies. Check for leaks. Before switching on the power supply, run the pump hot, then cold to prepare it in accordance with the manufacturer’s instructions. Once you are certain that all work has been carried out correctly, switch on the power and test the installation.
Installation of separate pump type
The plumbing principles are pretty much the same as for the all-in-one type. The big difference being that the water is routed either before or after the shower mixer to a separate pump.
As noted earlier, this may be a single or a double type. The single type is fitted between the shower mixer and the shower outlet. The double type is fitted to the hot and cold supplies before the shower mixer. With this double type, it is therefore possible to boost the pressure and flow to other appliances as well.