On Sun, 3 Oct 2004 23:21:51 +0100, "James"
wrote:


"Derek *" wrote in message
.. .

This is a variable off delay timer/relay. Cost = £35.00 but is all you
need except for a bit of din rail to mount it on.

You don't really need a circuit digram. The unit takes 240v power and a
pair of contacts close when power is applied, they stay closed after power
is removed for the duration selected by a knob on the front (up to 10
mins) . Connection to the unit is via screw terminals so no other
plugs/sockets/connectors needed in yr. box.



This is difficult to discuss without a diagram - but isn't there a danger
that the power to the pump will also be fed back to the boiler switched
live, enabling the boiler to fire again during the pump overrun time?


I see what you mean but it's not unavoidable the relay contacts are
isolated from the power/control input to the relay. So (figuratively
speaking) breaking into the power feed to the pump (only) and using that
as power/control inpt to the relay with the contacts switching another
source of (clean) mains power to the pump, should work OK.

DG