Wirsbo Manifold Question

[kwright]

Can anyone tell me - referencing the attached photo - what the L-shaped fitting attached to right side of the top manifold is for? In other words, what is this fitting.

Just curious...

 

[PAToyota]

Sort of blurry photo, but it should be the air bleed valve to remove air from the system.

 

[Ron Lombardo]

Its the purge valve on the return manifold ... see the top those are the location to put zone valves ... you close them and pump water into the system and open the little valve and let the air out 1 zone ata time
Ron