Heater or Tap problem

[hazey11]

Hi can someone offer me some advice please. I have a small hyco inline heater and tap serving my kitchen sink. Recently there has been a sweet spot on the tap that i have needed to find to get the heater started. Now i need to jiggle it round loads to get the heater started. (I can tell when it comes on as the lights flick). Is this likely to be a tap problem or a heater problem? Should i try changing the tap or get a plumber around?

i have tried turning the cold feed to the tap off and this didn't improve anything.

heater looks like this : https://goo.gl/images/vhX9Vm 

Thanks for any advice, 

Alex

 

[Ardet R]

It sounds like the flow switch internal to the heater is not operating correctly, presumably blocked with scale or gunge.

I would suggest that a plumber may be able to clear the blockage, from a non plumbers point of view!