I recently (2 months ago, its been busy) started up a pair of Carrier 30MPW Chillers, 45 tons a piece.
I piped these chillers in a reverse return configuration on both the condenser and evaporator. The chilled water side is primary secondary with a hydrolic separator. When I first started these chillers the number 1 chiller was alarming low flow on the evap side. I had to pinch down the outlet valve (approximately 20%) to make the flow switch close and allow the chiller to run. I had a Carrier rep onsite for the whole start up, though he did not understand reverse return. I believe that the flow switch is not calibrated correctly and needs to be replaced but he does not agree. Reverse return = equal flow through all equipment. The other chiller runs just fine and has adequate flow. The pump is sized correctly, and probably about 25-35 gpm oversized. I have yet to have a flow balance (don't kick me on that). I am just curious what y'all think about this situation.