Central Heating valve problem.

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
TerenceBooth wrote:

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.