In article ,
Bob Minchin wrote:
Geoff, Is there a pattern to the type of faults you see?
Maybe dry joints due to thermal stress or relay contact dirt/failure.
In the field of electronics I worked in, components were very reliable
unless over stressed in some way. Heat and dirt were a source of
problems though.
Conformal coating used to help a lot but I doubt that they use that.
Maybe the boiler designs are cut to the bone?

Cynical me says they are designed to fail.
Heat shouldn't be a problem with a decent modern boiler.

--
*Why do they put Braille on the drive-through bank machines?

Dave Plowman London SW
To e-mail, change noise into sound.