vokera linear 24 flashing code "C0".

[coltmanneil]

Could be an easy one for you guys on here.
Have an 8year old Vokera linea 24.When i got in there was no lights on boiler.Later found the on/off heating/water and water only selector button had broke.Therefore it would not turn the small switch on the PCB board.
To get the water back on i just used a pen top(non metalic)to turn the switch on on the board,this worked fine although when i go to water only it comes up flashing C0,which is not one of the error codes i have in my manual.It could be that I am turning this switch too far and the switch mabe of the scale????But i have also notice the cover for the Combustion switch cover is missing in the top right-hand side of the control panel.I have got the heating/water on now no problems until i get a new selector button.Can anybody tell me what this cover on the switch is for,it looks like an anti-tamper device.The Bolier was serviced in Feb by Vokera,unfortunately this is also the 1st time i have noticed this cover missing.
Help appreciated.

 

[petit_pablo]

CO means its in combustion mode, used when servicing the appliance. Under that cap thats missing is a small black button, press that in and see if it clears up the problem.

However, If its coming on randomly the display board is usually faulty

 

[coltmanneil]

Could you tell me if this white slotted cover over the "CO"switch needs to be installed or is it purely cosmetic.I could of lost it a while back,but can replace it as they are still available online.
Also What does this "CO" test switch actually do for the engineer when servicing???
Thanks for the repy.

 

[petit_pablo]

The slotted cap is purely cosmetic to stop accidental activation of CO mode.

CO mode forces the boiler into maximum rate in heating mode and allows the service engineer to test the boiler fully.