Vaillant f27 ecoTEC plus 837 F27 code

[RBG]

Hello all.

Had a call out this morning to water dripping from under boiler. Found to be a split expansion vessel - the outer metal case had split on joint at bottom and was dripping out quite badly / water inside boiler. No fault codes. Replaced expansion vessel refilled system etc. Attempted to turn on and got F27 code. Fault guide says that this is incorrect flame. I have isolated boiler / made safe etc and am going back on Monday now to sort out. I am going to speak to Vaillant technical on Monday. Is there anything I should be looking for? A few searches online suggest a number of electrical problems it could be, including PCB which may have got wet from leak but didn't look like it (but not sure)

Any thoughts greatly appreciated.

 

[ShaunCorbs]

Did you turn the power off ?

 

[RBG]

Did you turn the power off ?

When changing the vessel yes? yes i did. I then turned back on after changing to get fired up again which it didn't and I got the f27. I tried to reset to no avail. I have left turned off at house.