Heating system question

[jamie1992]

Can anybody tell me what this link is for on my heating system (see image with red arrow). It links just after my pump and is connected to the return after the cylinders coil. The isolation valve is cracked 3/4 of a turn.

 

[exedon2]

Manual system bypass so there can be circulation if both motorised valves close and boiler has a pump overrun.

 

[jamie1992]

Manual system bypass so there can be circulation if both motorised valves close and boiler has a pump overrun.

Thank you for the response, so can this valve be fully shut? Are does it need to be cracked for the overrun as you stated?

 

[exedon2]

Leave it where it is

 

[ShaunCorbs]

Tbh should be changed for an auto bypass next time someone drains the system

 

[Ric2013]

Interesting lagging technique

 

[John.g]

Thank you for the response, so can this valve be fully shut? Are does it need to be cracked for the overrun as you stated?

A ABV will not work satisfactorily in most cases with these A rated pumps, so probably as well off with the manual bypass, however it may be passing too much at 3/4T open, if you care to note the present pump power (watts) shut the by pass briefly again note watts and then reopen it to the original setting & watts., Post the pump model and setting mode and the exact by pass can be derived and if excessive the bypass can be altered.