Q&A: Showers

June 2003

Q1 I have an electric shower which worked perfectly well for about a year but now it gets very hot and then goes very cold. Can you tell me what's gone wrong with it?

I would suggest that the shower head is blocked. The holes in the head acquire a build-up of scale over time. If this scale reduces the flow of water through the heater, the water will overheat and the thermostat will cut off electricity to the heater when the water gets too hot - you will then get a cold shower. Either remove the shower head and descale it or buy a new one. If you buy a new one, be certain to get the correct head for the shower, otherwise it may not work properly. Some shower heads have a cleaning mechanism, all you need to do is rub the shower head to descale it.

Q2 In the bathroom we have the sort of shower which pushes onto the taps. This is fine for washing hair but no good for having a shower. Would it be possible to fit a proper shower in place of it?

One choice would be to fit a diverter tap instead of the existing taps. The advantage of these taps is that they can either be used as a shower or as the bath taps, depending on which way the lever or plunger is pushed. Changing the taps requires a certain amount of plumbing but not too much for most DIYers. However, if the taps have a cold water feed directly from the mains then the diverter shower may not work well - you may not be able to get an even temperature flow of water or it may stay too cold.

Q3 Our electric shower is very old and does not get the water very hot. I understand the new ones are much better. How difficult would it be to replace the old one with a new one?

The plumbing required is quite straightforward - it is just a matter of turning off the water and removing the pipe from the shower then reconnecting it. However, the new electric shower will be a lot more powerful than the original one and so a larger cable to the consumer unit (fuse box) may be required. I suggest you ask an electrician to survey the system and let you know what work is required.

Q4 We are about to change the mixer shower for a newer one - we have been looking at the various types and were wondering whether we should fit one with a thermostat or not.

I appreciate that the thermostically-controlled showers are more expensive but for safety reason I think they are a good idea. In some houses, if a cold tap is turned on while the shower is running, the shower will get very hot. The thermostat will not allow this to happen even if the cold fails completely. Thermostatically-controlled showers are needed especially if there are children or elderly people in the house that use the shower.

Q5 I have just fitted a shower and it works well. But what is the use of the plastic ring, which looks like a large cup holder?

I'm surprised that the instructions do not tell you. The ring fits onto the same sliding rail for the shower head holder. Then the hose to the shower head is passed through the ring so that the head will not dangle in the bath. This is a requirement of the plumbing regulations. It is to prevent contaminated water (from the bath) being sucked back into the water main.