What I have genuinely loved about this forum, for ages, is the way some people like to have a discussion, like to try and educate, like to open up the mind to thinking and, completely opposite to that, the way some others will try to close down any discussion, try to hide information and pretend that what they work on is simply too abstruse for a layman to comprehend. Of course, they'll hide behind "call a professional" all the time, and that is what has been done in any situation pertaining to boilers and central heating (by me, as already stated), but it truly blinkers their vision, because instead of answering questions, they fall back to a form of protectionism and they try to pose their own questions (to the OP and other helpful forum members) that are solely intended to belittle others, challenge them and dent their confidence. This is not how people will learn anything effectively, so they are broken forum members in this regard. I prefer the folk who say - "this looks like this is wrong, and maybe you could try this to validate if this happens, if it does it probably points to this"; then at least you can talk to the professional who visits your home. Heck, it might even make it cheaper. I think - stereotypes inexcusable - that the forum members who try to shut down conversations must really like it when little old ladies call them out to just "fix it". I'm not saying they're an easy mark, but they could be for the unscrupulous. I learned quite a bit yesterday - and I liked it. Until the thread descended into posturing, again.