Electric water heater

[Capealava]

My electric water heater keeps going off and on. When is does come on the hose shakes about like there is not a steady stream of water leaving the heater. It is an expensive British made unit and I have had it for 5 years with no problems. I reset it and the light comes back on and then invariably it turns off again and water does not come out of the shower when the shower is turned to hot water, then it comes on again  

[mahjongguy]

Sounds like there is not enough flow into the heater to keep the elements from overheating. Remove the input hose, see if there's a good flow into a bucket. If so, see if the there is a clogged filter washer. 

[Crossy]

Yeah, I would start off by checking the flow rate.

 

There is often a gauze filter at one end or other on the inlet hose and the hoses sometime collapse and restrict the flow.

 

[Capealava]

Thank you for replies I will look into it.