I recently received a call from a friend whose electric shower unit in his bathroom had suddenly stopped working correctly, even though the water flowed it was not reaching temperature, and I assumed the heating elements in the shower water tank must have failed.
After testing the elements and checking connections etc, I could not find any fault, other than two micro switches that did not always operate. I opened the water stop valve to the property by an extra 1 1/2 turns, the shower worked perfectly as before.
The low water pressure diaphragm in the shower unit (this is a safety device to avoid scalding) was not activating the two micro switches fully, which allow the electrical current to flow to the heating elements.
As my friend had not altered the position of the stop valve, the loss in water pressure must be due to the local water authority lowering it, I assume to save water during the summer months.
So before you call out your local electrician or plumber, check the water pressure has not dropped, my friend did say he had noticed a difference in water flow at his sinks cold tap a few days earlier but didn’t think anything was untoward as the water still flowed, albeit a little slower.
Safety tips :- Always switch off the electrical supply to the shower unit at the consumer unit and remove the appropriate circuit miniature circuit breaker (MCB) or fuse before removing any covers or working on any electrical equipment / circuit. If in doubt always use the services of a qualified electrician. Don’t remove or alter any safety devices / sensors within the shower unit enclosure in order to get it working, without these devices / sensors there is a high risk of scalding or even fire occurring.