the HVAC industrial plant & office system is chilled water, 400 tons, two chillers.
the distribution system to the office raises about 20 ft to the roof across a crane bay and drops the same distance after a horizontal run of 60 ft.
i am concerned about air lock in the supply side and a little less concerned about the return side of the office piping.
i can hear what sounds like bubbles passing the control valaves in the office units. it seems that the office always gets less cooling water and is "humid" on marginal days. is this a ligitimate concern?