lockout problem with WB greenstar 35cdi

Replaced an old boiler with one these for a customer about 8 month ago.

In the last few months the boiler has been locking out intermittenly (F7 fault code) requiring a reset on the front panel.

They called WB and the engineers have replaced
1. Gas valve on the first visit
2. electrode on the last visit last week. The customer was told that everything checks OK when the engineers ran the diagnostic using his laptop.

The customer has contacted me again to say the problems still exist. They are living wit it but it's nuisance. I am hoping to get there when the engineer next comes out.

Has anybody experienced similar problems WB Greenstar CD boilers ?

I install bundles of WB and the only problems I have ever had (Even the one I fitted in my house) was with the 35CDi. I talked to the reps at the trade show and they denied all knowledge of any such problems. I know they had a batch go out with the wrong flow restrictors in them, so look out for this when commissioning but your problem is not one that I have come across.I had my rep visit a site the other day (arms laden with goodies but no bacon sandwiches) and he says that the 35's are still made in Germany and there have been a few problems with them and I do also know that WB have just taken on a load of new engineers so some of them are possibly not as good as the old hands on the firm.
F7 fault is either a faulty elecrode, PCB joint or a blocked flue.
I would give them a call and tell them that your customer is thinking of buying new Bosck kitchen appliances and is having second thoughts due to the problems with her boiler, or give your rep a call and tell him to sort it on your behalf.
Hope this helps....