Strange power shower problem

tcall

I few months ago the power company blew a few of our appliances with a faulty generator. They replaced the items, which included a mira sport power shower.
However, recently the shower has started acting up.
On LOW water comes out, but it's cold (as i think it's always been)
On MEDIUM or HIGH the water comes out, but the low flow light comes on, and again the water is cold. It just wont heat up.
The only way i can get around it is to unscrew the shower head and wiggle the hose for ages and then try again. Sometimes it then works, and sometimes i have to try wiggling it more. I have checked the hose and there is no blockage, and the water pressure is high here.

Any ideas what the problem might be and how to resolve it? My old shower was fine until they blew it :mad:

Canucklehead

Good evening: Excellent advice is available here.. http://www.showerdoc.co.uk/faq/index.html

HTH

Canucklehead

tcall

Thank you muchly