Spirovent Placement

Justin Gavin

I designed a light commercial system and improperly placed the Spirovent and expansion tank on the primary loop because the boiler is pumping into the return.

The loop is 2" and is also feeding into a shot feeder.

My thinking is leaving the 2" spirovent in place and installing the expansion tank on the supply side of the secondary loop on the suction side of the main system pump.

My question is, is it still nescessary to use another air purger/vent for the expansion tank? And would the system be affected if I keep the spirovent on the primary loop?

Thanks in advance.

Justin Gavin