ticking 3 port motorized valve

[slapheadtwo]

Hi, every now and again the motorized unit on my 3 port value ticks, about once a second. It sounds like the motor has turned the valve fully open, causes a micro switch to cut the motor and as soon as it starts to return under the spring the motor starts again.
It happens once or twice a week and normally when heating only is called. Occasional the rads fail to warm up and we switch the hot water on for 5 mins and then everything is OK. I replaced the 3 port valve about 5 years ago. Has it gone again or do you thing there is a wiring issue?
Thanks for any help.
Regards
Kevin

 

[stevetheplumber]

sound like its on its way out im afraid

 

[diamondgas]

:iagree: Usual suspect is the motorised valve..

 

[hammers4spanner]

Tick tick boom!!