Vokera boiler locking out

I've seen a few posts about this issue and wonder if anyone can offer advice. We bought a cottage that has a 9-year old Vokera Maxin 28e boiler controlled by a Danfoss 715 time switch. While it provides adequate hot water for kitchen, bathroom etc, we soon found it was locking out every 9th or 10th start. A service file showed this fault ran right back to the month after installation (May 2000) with more visits than Blackpool Tower and old bills for replacing: sensor electrode, start electrode, gas valve, o/heat stat, pump o/run stat, ignition unit, diaphragm. Last October a technician replaced the gas valve (again). Other repairs included : "remove air restrictors", "re-pressurized expansion vessel", "set htg gas rates", "adj. soft light", "cleaning fan, venturi, heat exchanger and burner". None of this has worked for long, if at all. Any thoughts?

Yeah,change it.

Or pap it right back to Vokera on a fixed price repair of £170 odd or £290 for their one plus service which includes the fix and a year's contract.

Tony.

Thanks for that suggestion, I didn't know about those deals, might try one before giving up entirely. But I'd really like to know what else it could possibly be since it seems to have almost totally re-built since installation.

You seem to have had everything changed apart from the main pcb.

The strange thing to me, is that it was never fixed by Vokera under warranty

This should have been an ongoing fault that was fixed by them, even if it meant replacing the boiler.