Vokera Linea 28 - no green LED but power seems ok

[lubemonkey]

Hi all,

I've inherited a Vokera Linea 28 gas combi boiler at a property I'm refurbishing. I've only fired the boiler up about a half dozen times in four months but it's always worked fine - until last week.

With power on at the wall, the green LED remains unlit, as does the red LCD display. The timer clock can be heard whirring merrily away. Changing position of mode selector or either temp control changes nothing.

If I remove the small blanking plug to bottom right of CH temp control, and press in the combustion switch (believe that's what it is called) nothing happens either. If I turn off the power, depress the switch and turn on the power once more, the boiler fires up very happily with green LED lit and rising numbers on the red display. When I release the switch everything goes off again.

Is there an internal fuse that could cause this?
All electrics are turned off at the MCB whenever the property is empty - which is every night plus weekends. Not sure if that might affect anything but thought I'd mention it.
Is there a lockout mechanism that's kicked in and needs resetting? I know the weather's getting colder but it's yet to go Baltic in London.

Anyone had this happen to them or know what the SP might be??
Thanks in advance,
Lubemonkey

 

[ianmcd]

with the selector Knob at off is there a figure on the red display? does a figure appear when you select HW or HW+CH ?

 

[lubemonkey]

Thanks for pitching up ianmcd. In answer to your questions:

"With power on at the wall, the green LED remains unlit, as does the red LCD display. The timer clock can be heard whirring merrily away. Changing position of mode selector or either temp control changes nothing."

So no and no. It would be nice if the lights were on and I was getting an error code but there is nothing.

Any thoughts on what may be happening?
Cheers,
Lube

 

[Agile]

Usually thats because you have been heavy handed with the selector knob and the shaft has snapped!

If course many say they only very gently touched it!

Looking from the rear can identify if thats the cause. But messy there are a bird's nest or wires to the PCBs.

Tony

 

[ianmcd]

The shaft on the control knob has broken off a very common problem with the Linea surprised it has lasted this long to be honest, its not an expensive part about £11 if I remember correctly not really hard to replace either, the old one will be one piece the replacement will be two piece, if you dont have a display then the PCB is set to the off position so when you replace the new control knob make sure it is in the off position too before marrying the control with the PCB and you will be fine, if the new control knob feels firm when moving dont force it you have done something wrong if it does

 

[lubemonkey]

Spot on with the advice guys. After isolating the leccy I got in to the PCB with the pots on, and the spindle on the back of the mode selector knob had snapped. As had the one for the CH temp.
I turned the mode pot to on with the remains of the bust spindle and the boiler fires fine.
I've ordered two temp control knobs (Vokera part number 1859) and one mode selector knob (Vokera part number 1860) for a full refurb with the updated two part knobs. Got them for £3.50 each inc. vat.
Just being long winded with this in case it's an easy win for someone on a search.
Many thanks again for your help!
Cheers,
Lube

 

[ianmcd]

glad to have been able to help the good news is the replacement knobs are in two parts and I have never had to change any of the new design they are a lot stronger, it is possible to install them wrong so just take your time and you should be fine