Using FluidCooler for Water Economizer at Low Temps

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I would like to model a baseline water economizer for a chilled water plant serving a datacenter--following air inlet temps of ASHRAE 90.1 Table 6.5.1.2.1. For an air-cooled economizer loop (zone 4A), the design inlet drybulb from the table is 25 degF.

Within OpenStudio, while attempting to use a FluidCooler:TwoSpeed I discover that I cannot set the entering air temperature below 32 degF. Am I doing something wrong, or is the FluidCooler model constrained to greater than 32 degF? I have checked In/Out and Engineering references and don't see any indication of the limits of the FluidCooler model. The object's performance curves are not exposed in the OSM file, so I cannot see if there are limits on the curve.

Thank you in advance.