Worcester greenstar 42cdi heating issue

[giarc00007]

H everyone havnt posted for a while hope everyone is good. Got a call to above boiler today customer saying fault with heating and e9 fault code showing. Hot water is fine. I couldnt get fault code to appear but looking in manual e9 states overheat issue. All thats happening is pump pulsates for about 5 seconds maybe 5 times then stops spinning. Linked out overheat stat but no difference i was thinking pump but just wondered if anyone had any advice?

 

[Inverness]

Check the diverter valve I had the same problem and the diverter valve was sticking.

 

[giarc00007]

Check the diverter valve I had the same problem and the diverter valve was sticking.

Thanks will check that