Indirect Cylinder 'Return to Boiler' tap

[Apacs]

Hi guys
I am looking for some advice regarding the 'return to boiler' tap on my Hercal indirect Coil cylinder.
I changed the taps in the bathroom the other day and in my quest to try and locate a tap to turn off the hot water supply, I may have turned the return to boiler tap off at the bottom of the cylinder. Problem is, I do not know whether this tap should be open or closed. Since changing the bathroom taps (there was no shut off tap for the hot water, so i had to drain the tank), I do not appear to be getting any hot water and wondered if my problem may be linked to the return to boilertap being shut off.
Any advice would be appreciated
Thanks

 

[danielp]

yes it should be open to allow circulation we use these to balance the system by turning them down a bit but open it fully and see how it goes