Help request - Vokera Excell 96e over-temp

[robbieb]

Hope someone can help )
My Vokera Excell 96e went into over-temp fault yesterday morning, so I reset and it was ok; did it again this morning, so again reset ok, but now it has done again and when reset it repeats the fault, so won't work.
I have listened to the startup after reset and it sounds to me like the pump isn't working; burner fires up, then you can hear the water start to get hot, the burner shuts off, then continued 'bubbling' noises and then the boiler goes into over-temp failure...
Can anyone advise how to test the pump? I've checked the voltage at the board and it's ok (~240v). Can anyone alternatively suggest other items to test?
Late last year the boiler had a new PCB and was serviced. I'm not a gas fitter but I am an engineer and cold, so am keen to try to diagnose the problem myself if possible, to get the system going again asap )
All help hugely appreciated!!
Robbie

 

[kevplumb]

View media item 667
undo the screw marked bleed (cloth handy)

you can see the shaft turning

if stuck you can spin it with a narrow screwdriver

 

[robbieb]

Kevplumb,
A BIG thanks to you for advice...I'm off into the garage to check that now
Cheers again,
Robbie

 

[robbieb]

Ok, I've just seen the pump shaft turning, so I guess the pump must be working... the boiler has fired up this time and seems to be running now I hate intermittent faults, they're always a nightmare in cars and the like, so I guess it's the same for boilers....
Anyway, does anyone have any suggestions for stuff to test??

 

[glasgowgas]

Ok, I've just seen the pump shaft turning, so I guess the pump must be working... the boiler has fired up this time and seems to be running now I hate intermittent faults, they're always a nightmare in cars and the like, so I guess it's the same for boilers....
Anyway, does anyone have any suggestions for stuff to test??

replace pump head, its on its way oot