I have a Horstmann timer controlling a fully pumped sytem with a
mid-position valve. If HW and CH are selected and running, then switching CH
off does not cause the valve to move even at the end of the on/off cycle.
The only solution is to disconnect the mains from the system sometime during
the off period when the spring moves the valve to the correct HW-only
position.
Is this a wiring error on my system or a problem with this type of valve?.
Can anyone help with a solution?

Alan Booth

TerenceBooth wrote:
I have a Horstmann timer controlling a fully pumped sytem with a
mid-position valve. If HW and CH are selected and running, then
switching CH off does not cause the valve to move even at the end of
the on/off cycle. The only solution is to disconnect the mains from
the system sometime during the off period when the spring moves the
valve to the correct HW-only position.
Is this a wiring error on my system or a problem with this type of
valve?. Can anyone help with a solution?

Alan Booth

Do your rads actually continue to get hot when CH is satisfied?
I ask this because you usually can't tell what the actuator of the valve is
doing by merely looking at the lever which is for manual override.

"TerenceBooth" wrote in message
...
I have a Horstmann timer controlling a fully pumped sytem with a
mid-position valve. If HW and CH are selected and running, then switching
CH
off does not cause the valve to move even at the end of the on/off cycle.
The only solution is to disconnect the mains from the system sometime
during
the off period when the spring moves the valve to the correct HW-only
position.
Is this a wiring error on my system or a problem with this type of valve?.
Can anyone help with a solution?

Alan Booth




Has it always been like this - or did it previously work in the way you
expected?

If it's always been like this, it could be wired wrongly or - as someone
else has suggested - you may be misenterpreting what it is *actually*
doing.

If its behaviour has changed, it's almost certainly due to a duff
microswitch within the actuator part of the valve. If this is the case, the
simplest solution is to replace the actuator - which you can do without
affecting the water-handling part of the valve. [The alternative is to take
the actuator to bits and replace just the defective parts, Some contributors
to this NG advocate this, but I personally think it's a bit too fiddly!]

Roger