Linking multiple returns

[mfgs]

Do you guys put non return valves on central heating returns when there are lots of separate zones on a system?

 

[ShaunCorbs]

depends if your not using a port valve and a pump for each zone then yes need a single check or swing valve

but if using a port valve a check valve isnt required

 

[mfgs]

2 port on each zone but only one pump for all zones. Worried about reverse circulation with only one zone on.

 

[ShaunCorbs]

2 port on each zone but only one pump for all zones. Worried about reverse circulation with only one zone on.

you should be fine aslong as non of the circuits combine eg flows linked after port valve

as the port valve acts like the nrv

 

[Last Plumber]

2 port on each zone but only one pump for all zones. Worried about reverse circulation with only one zone on.

It should be fine with zone valves fitted. I do always fit a gate valve on each return on multiple zoned systems though. To help with balancing. Just like you would on the return form a DHW Cylinder.

 

[Best]

You shouldn’t get any circulation, but where any returns come off the main return level or rising to one or more radiators, then heat will creep into that to some extent.
So have the returns ideally dropping to any extent from the main return to prevent that.