Why repair a terrible boiler? Your just wasting money. I've replaced two 3 year old ferrolis before now because the landlord had had enough of breakdowns. Would never touch/work on one again. As for vaillant, all boiler have their troubles...but serviced properly and with a 7 year warranty you can't go wrong...ecotec plus.
I agree, if you read the thread i WANTED to replace it with a Baxi DuoTec/7 year warranty BUT i presumed the existing flue could be used, it can not so it's not just a simple boiler 'swap', looks like i will need scaffold for the tile 'shroud' PLUS loft access/working up there to fit flue will be a nightmare as the insulation is 3 ft thick....
I have spent about £1500 JUST to keep it going the last 2 years !!
I never new Vaillant do a 7 year warranty boiler !!
I 'think' there is a way to put a 90 on top of boiler outlet and put it out through outside wall, it will not look as nice, but would save a LOT of hassle/money...????? What do you reckon, i could add pics if necessary...