In message , raden
writes
In message , Paul Barker
writes

Good point Geaff, this is why we have to prove thermisters by geting
the test data and proving it functions correctly.

I recently changed a Worcester 240 pcb for a customer because the relay
was frequently making and breaking. Discussions with Worcester
confirmed
my choice of part. Now they've phoned me to say it's doing it again.
Perhaps it was the thermister? I've bought one to take round. If I was
wrong about the pcb I'll refund them in full and fit the correct part.
I've also taken the precaution of purchasing for £2.50 a suitable relay
from RS in case it's the relay. I hadn't learned from my own lesson.
Relay clattering like mad, must be the relay, customer wants it fixed
same day, can't get a relay in time round to hrpc for a pcb.

One bug bear, suppliers won't take pcb's back, so now that's another
pcb in my stock.

Have you any take on this particular problem?


Yes - relays don't normally chatter because they're faulty, they
chatter because there's a fault in what's driving them

Also ... look at my website www.cetltd.com

--
geoff