"Jim Lesurf" wrote

My experience is that almost any type of conventional relay will end up
causing problems if the unit is used for many years. Avoid if at all
possible. Solid state relays would be much better if you can find one that
suits your purpose.


I don't share your jaundiced view of relays. Whilst they are not suitable
for every switching requirement, there are many applications for which they
are the most logical choice. I suspect your negative view is based on the
effects of cost-cutting by equipment manufacturers. SSRs are a lot more
expensive than ordinary relays and they have their own limitations. They
only make economic sense when very many operate-release cycles are expected
over the equipment life.

I might cite the two relays in the control box of my 30-year old central
heating boiler. The boiler is well past it's sell-by date and due for
replacement in 2010 (esp if I can get Gordon Brown to chip in £400 :-), but
the relays have never been any trouble.

David.