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[EnergyPlus_Support] Unitary System Problem

I am trying to model a residential home for my Master's Degree Plan 
B paper and am running into problems with the unitary system.  I am 
modeling the home as a single zone and using the 
FURNACE:BLOWTHRU:HEATCOOL as the plant.  I have specified the fan, 
gas coil, and DX coil.  When I run the model, I get the following 
error (60,000 times):

volume flow rate per watt of rated total cooling capacity is out of 
   **   ~~~   **  ...VolumeFlowperRatedTotCap=3.085E-006 Occurrence 
info=CHICAGO IL USA TMY2-94846 WMO#=725300, 04/07 17:30 - 17:45
   **   ~~~   ** Expected range for VolumeFlowperRatedTotalCapacity=
   ** Warning ** Enthalpy out of range (PsyTsatFnHPb)

Based on the text of the error, it appears that the airflow rate is 
too low and the cooling coil is having problems.  I think I modeled 
everything correctly, put the unitary system on the air loop and 
connected it to the zone using a DIRECT AIR component as described 
in the Input/Output reference.  I am modeling a 4 Ton cooling system 
with 400 CFM/Ton.  This amounts to about 14,000 Watts and 0.75 m^3/s 
airflow rate.  When I do a quick calcualtion, this should be about 
5.35e-5 m^3/sW (0.75/14000) and should be right in the middle of the 
acceptable range (3.35e-5 to 6.7e-5).  For some reason, the model is 
not seeing the airflow or is incorrectly calculating the cooling 
load.  I was wondering if anyone has any suggestions, or has run 
into this problem in the past with the Unitary system.  I am using 
the FAN:SIMPLE:ONOFF component with 0.75 m^3/s flow rate.

I would really appreciate any suggestions/help..


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