MissF.
Please do not think ill of my colleagues. Our situation here, as FOC advisors, is that many people come here to try to validate a form of thinking that is largely dictated by a genuinely biased media.
When those thoughts are not validated people become defensive and huffy - unlike you.
The reality of plumbing in the 21st century is that all of us 'practitioners' are played like puppets by manufacturers. Of course it is us who then have to communicate the 'bad' news in whatever form it comes to you our customer and, human nature being what it is, the messenger is lined up and metaphorically 'shot at dawn' despite being perfectly innocent of any crime whatsoever.
As a consequence, we tend to get a little defensive...
When Chris refers to a 'pile of poo' he is using a colloquialism which translated means this make of boiler has a very poor reputation for reliability and, let's be polite here, is 'lacking in support' from its manufacturer. Further translation means we get even more flack about this type than many others 🙄
If I may be so bold, in future try asking the plumber how his price is made up when he quotes you. If, by some chance, they are being some form of dishonest it would send a shot across their bows. If not, by asking it in an open way it is simply a question not some form of accusation.
Two last things.
1 - As an intelligent person please please please do not assume that because someone worked on one part of your system, anything that happens at any point in the future is automatically their fault. To do that will instantly destroy any relationship and trust the engineer has in you and you'll have to start again. Far better to ask an open question and ask if or how they might be interrelated.
2 - Take an interest, and you'll be surprised what you pick up, and more importantly the engineer will be far more inclined to help you.
Hope that clarifies somewhat!
Have fun and please come back to ask again when you need help.
Lastly, sorry to go on ,
Blimey Dave you swallowed a dictionary ? agree with you totally mate but you do go on ha ha . Good luck with the show bud . Cheers Kop