Faulty Shower?

[notgotaclue]

I have just moved into a new house and the electric shower seems to be faulty. It allows me to select the temperature and heats up correctly but then after 30 seconds - 1 minute the water temperature goes cold then after 30 seconds - 1 minute it heats up correctly again and this goes on. Does anyone know what the problem could be?

[ianmunt]

sounds like the thermal cutout is in action.Is the showerhead scale free.If there is insufficient flow the cutout operates as a safety mechanism.

[matt1e]

the same thing applies when there is low water pressure

[notgotaclue]

Thanks, the shower head looks clean and as far as I can tell the water pressure is also ok. It doesnt drop in pressure when the temperture changes.