"geoff" wrote in message
...
In message , Andy Morris
writes
Hi, I just wondered if anyone knows the answer to this one?

I have a 4043H1056 valve that does not automatically shut when power is
removed.
The spring return seems to have failed. - Does this require a whole new
valve unit, or can just the actuator be replaced?
I mean is the spring part of the valve, or part of the drop on actuator
block?

( Because the vavle does not close, the pump is always on and boiler is
always on due to the micro switch I guess? ).

This indicates the valve is not even starting to close since the microswitch
only makes in the last degrees of travel. Possibly the contacts have
welded.

Also, the manual lever on the valve does not seem to grab anything. There
is
no resistance for moving it, and it just stays without the need for
locking.
(and does not close the valve either).

That's normal when the valve is open.


It depends on the age of the actuator. On some older (Honeywell) ones
you cannot remove the actuator head, on the newer ones you can.

Once the spring has gone soft, there's not much you can do with the
actuator head.
Since the microswitch is not opening I would suspect stiction in a rotating
part (motor or valve) rather than the spring going soft. If you get the
actuator head off the valve should rotate freely.

Alan