It sounds like you have fiddled with an "oxypilot" assembly from the description of the copper wire/white wire. My advise would be not to use the fire until checked by CORGI reg. engineer. Pilot may be going out because it is drawing in fumes, making pilot flame unstaible and t'couple cooling...
The makers have to abide by the regulations. CORGI do not manufacture PTFE they will just say if the stuff is good for gas or not. If it has been tested and passed for gas usage then thats the end of it.
The simple answer is just accept what the manufacturers of PTFE state.
If its meant for gas then so be it and visa versa.
It aint nowt to do with if you're a plumber or RGI with an oppinion its "what it says on the tin" that matters.
Short of conducting all sorts of agile...
How long does it take to diagnose a failed fan unit ?
What makes you so sure that its not the problem.
Any RGI worth their money could diagnose a faulty fan within a couple
of minutes of removing the combustion chamber cover.
Point taken mate.
Just out of interest, do you charge more for a BBU that takes 1 hour as opposed to a wall hung that takes the same time ?
I only ask as my boss always justifies a higher charge for BBUs as they are "2" appliances.