F Murtz wrote:
Every single competant person started out not having done this job before.
I work on the principal that if someone else can do it I can.

Everyone with a certificate was taught by an experienced person and has
done the job, or a very similar one, many times during training. This is
(in theory) why gas fitters take on apprentices, purely to ensure that
they get "hands on" training. I watched it work when a gas fitter was
servicing my boiler recently. The apprentice did the work, while the gas
fitter watched him *very* carefully, and made mostly polite
recommendations while he was doing it.

A recent instance ,I am not a mechanic, I am not an air con technition,
but I just replaced the condensor in a 316i BMW including the vacuum and
then regas which is not for the faint hearted.
Just look at this mess.

https://www.dropbox.com/s/9clefzv645t4g8z/bmw%20007.jpg
https://www.dropbox.com/s/1aep9eima1qbp34/bmw%20055.jpg

It is all back together and working now, but working on your outlook on
DIY I should not have attempted it.

The difference between that and what you are proposing is that if you
get the aircon repair wrong, then you end up being a bit too warm in
your car in the Summer. If you get a gas boiler repair even slightly
wrong, you and your family can end up dead or homeless many months later
as a result of the explosion and subsequent fire.

Also take note that even qualified people get it wrong on occasion, but,
as they are "professionally qualified", they should have adequate
insurance cover against any problems, as insisted on by their
professional bodies.

--
Tciao for Now!

John.