Thank you for taking the trouble to reply, Mr. Brown. Yes, it would seem an easy dilemma to resolve! However my installer first recommended the Vaillant, so I'm in a bit of a bind. I was (am) hoping, perhaps naively, there migh be someone on the Forum with actual first-hand knowledge, who could give some insight into whether Vaillant have a transient problem like teething troubles with a new system, or a more permannet one, such as being taken over by a company with a lower commitment to customer service.
Mark Boulding ● 1668d