Caution
When a flush or a running tap makes your shower swing between cold and scalding, the hot and cold supplies feeding it are not matched in pressure.
Low risk
A diverter that will not hold the shower, drops back to the spout or sends water to both has a worn seal, scale or a supply that is too weak to keep it up.
A pump that has got louder, pulses or keeps starting and stopping is reacting to a blocked head or hose, too little water arriving, air, or a failing pump.
Describe the job and get a fixed price from a local plumber.
