DU145 bypass valve - how to reset the dial

[PeterPlumber]

I recently had a Honeywell DU145 bypass valve fitted, with the factory setting of 2

Using data from my boiler and my pump, I calculated that it needs to be set at 3.5. I loosened the locking screw as per instructions and was surprised that the black dial moves with the red control - not very intuitive! I thought perhaps I hadn't loosened it enough so loosened it some more and the dial started slipping inside.

Eventually I removed the screw altogether to see what was going on, and finally discovered that the valve is multi-turn and the dial only moves half a point for each full turn of the red knob. (I think it's what they call an epicyclic gear).

How do I get the dial back to its reference position? If I turn the knob fully clockwise it reaches an end stop. Is this setting "1" on the dial? Can someone with a DU145 try it and let me know please.

Note - the instructions say don't turn it beyond position 6 (ANTI-clockwise) or it will be damaged. I haven't done this, and I know that it is still working and that I could set it by trial and error, following instructions on other posts. Still, I would like to set it according to my calculations.

 

[PeterPlumber]

Sorry - I got the clockwise and anti-clockwise the wrong way round.

It meets an end stop when I turn it anti-clockwise. Is this setting "1"?
The numbers increase when you turn it clockwise

 

[pfischer]

I spoke to Honeywell tech support and they confirmed:

Removed red knob and dial.
Push knob back on and turn knob ANTICLOCKWISE until end stop (this can take quite a few turns).
This is setting 1.
Replace knob with dial on setting 1.
Turn knob CLOCKWISE to desired setting (about 2.5 complete turns of the dial to move 1 unit).

 

[D_Hailsham]

Useful information - even if it is nearly a year late!