Honeywell Auto Bypass DU145

[Davidm]

I need to check the setting on the Honeywell Auto Bypass valve on my CH. At the moment it's set with the pointer on the orange cap pointing to the end of the white line with the number 1 just showing in an anticlockwise direction. I don't know if that means it's set to just below 1, or at the other extreme of beyond 6 (which it shouldn't be).

Also, how far out do I need to undo the locking screw for the cap before I can adjust it, and do I need pull the cap out away from the body in order to turn it. Reason for asking this is that the valve tucked away in a corner, and I can only do this by feel. I don't want to undo the screw to far that bits start falling off the dam thing.

[Cynic]

What has prompted your desire to fiddle about with the settings?

[Davidm]

I think that the auto bypass valve has failed in the open (or partly open position, the pipes on both sides of the valve are at the same (hot) temperature even when the CH and HW zone valves are open.

As a test I wanted to try and see if I could get the valve closed by adjusting it, but before doing that wanted to confirm what setting it was at.

Since last post hav loosened the lock screw, but the orange cap wouldn't turn in either direct. Took the lock screw right out, and took the orange cap right off, together with the black dial with the numbers on (noting the positions of both. Only the orange cap locates on the valve spindle, the black dial bit just rotates freely with in cap and when place on the valve. I can't see how the dam thing works! Have taken some pics of the bits:

With a bit of force I managed to free the valve spindle, replaced the orange cap and that now rotates many turns in both directions. Haven't turned it all the way in either direction yet in case it bu**ers the valve (installation instructions says not to turn it beyound position

6 or damage to valve can result).

[Cynic]

I'd not be concerned about a bleed through of the bypass. Many boilers run quite happily with a fixed bypass that allows sufficient flow to keep the b oiler happy even if all the radiators have shut valves. Take a look at a ce ntrifugal pump performance curve and see just how unimportant altered flow/ pressure is to the pump.