Purge valves on boiler supply?

GM_73

Hot water boiler seems to have purge valves on supply side? Am I missing something? How would it work?

Pump on lower boiler tap is pumping into the boiler, arrow pointing down. The higher tap (supply?) has purge valves. Any assistance greatly appreciated. Thank you.

EBEBRATT-Ed

You fill the system with water. Shut the valve in the supply coming off the boiler. The water will be pushed back the return lines through the system through each zone to the supply header and out the drain valve on the header.

You can close all the zone valves on the header except 1 and purge 1 zone at a time. Watch the pressure gauge and keep the water at 10-20 psi while purging. When 1 zone is done purging shut that zone valve and open another until you are done. Put a hose on the header drain into a bucket and purge until all the bubbles are gone.

There may be another way but we can't see the return piping. Where is your expansion tank?

GM_73

Thank you very much for the response.

So the purge valves are on the supply header? I imagine the gate valve on the supply would then be shut off, then appropriate valves would be turned off also, leaving one open, then open drain valve with hose attached into a bucket. Have always seen this setup on the return side. Odd.

EBEBRATT-Ed

@GM_73 it is odd but that the only way i can see it working.