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Andrew Smith
Andrew Smith, Engineer
Category: UK Plumbing
Satisfied Customers: 3629
Experience:  Domestic Gas, Commercial Gas, LPG, Unvented Hot Water, Part P Electrical, Commercial Catering
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My power shower has developed a problem.. The water pressure

Customer Question

My power shower has developed a problem..
The water pressure is fine, but the temperature has dropped. The best way to describe it would be that I have a thermostat dial, which used to be hot enough when dial was at the 11 o'clock position, now to get the same temp I have to turn it to 4 o'clock which means the pressure drops significantly. The water pressure is still the same at 11, the but the temp is the issue.
Has anyone experienced the same or have an idea of what the issue might be?
Thanks in advance.
Submitted: 1 year ago.
Category: UK Plumbing
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 1 year ago.
If it's easier please contact me by phone on ***********
Expert:  Andrew Smith replied 1 year ago.

Is it electrically heated?

Can you post the make and model?

Customer: replied 1 year ago.
we have to switch it on with a switch on the external side of the bathroom wall.It's a Mira Essentials 10.8kw shower.My apologies, I had added this on in the original post but I see it never made it to the final edit.
Expert:  Andrew Smith replied 1 year ago.

You heat exchanger will be scaled up.

Easier to replace it than clean it but sometimes just as easy to replace the shower than the part depending on cost.

You can get it from here;


Customer: replied 1 year ago.
Hi,Sorry for the late reply. Managed to strip the shower and check the element, all seemed fine but I descaled it anyway and put it all back together. No change. The problem still exists and I couldn't see anything loose, broken or burnt out inside.Anything else you can think of?
Expert:  Andrew Smith replied 1 year ago.

The only other thing I think it can be is the water thermostat. This should hold the tank at a specific temperature, perhaps it has lost its calibration

Customer: replied 1 year ago.
What does that look like and how can I check/replace it?
Expert:  Andrew Smith replied 1 year ago.

The power to the heating tank goes through it, so you could run the shower and monitor power in and out if it.

Part no. 5 on the picture

Customer: replied 1 year ago.
Is that not the thermal cut out switch? What should it be tested for and what should the level/reading be?
Expert:  Andrew Smith replied 1 year ago.

It should give continuity between about 45 and 75 degrees, perhaps it is shutting off at a lower temperature.

You can monitor it with a meter whilst running into the bath.

Customer: replied 1 year ago.
Would I not have to turn off all power to the shower before testing it?
Expert:  Andrew Smith replied 1 year ago.

You need to be careful with the front off, but you also need to check with the power on to see what it is doing to follow the power.

Customer: replied 1 year ago.
Ok, which setting should the meter be on? I don't have one reading temp.
Expert:  Andrew Smith replied 1 year ago.

Set to 240v ac, put the back lead on the main neutral or earth connection and then the red lead on the brown wire on the heater. If it keeps clicking on and off and the water is not hot enough then go back to thermal cut out and see if the power is doing the same on the outlet side