Dave W wrote in message ...

A 15 year old conventional B/F boiler probable only has a gas valve and a
thermocouple that are likely to fail.
A 5 year old condenser will likely have
fan, gas valve, thermistor, flow sensor, ignition electrode, flame
detector, fan stat, safety stat, and probably at least two PCBs.
We will have to wait a few years to see if current combi that everyone seem
to be buying are as reliable as you think, but with ever more bits inside
to go wrong I cant see it.

15 years ago you wouldn't have found a PCB in a car engine compartment
either, yet today they are commonplace and as a result cars are more
reliable and efficient.

A PCB in a harsh environment not necessarily a problem provided
sufficient care is taken in 'hardening' it. Also a modern
non-condensing boiler will have most of the additional components you
listed.

So that's you sussed then ;o)

MH