[Equest-users] Fan Night cycling and chiller operation

Rushi Quest rushiquest at gmail.com
Thu Apr 23 00:45:06 PDT 2020

Dear E-questers,

I am working on a nine hours, five days a week office building operated by
chillers to meet HVAC demand.
As per ASHRAE 90.1-2010 appendix G, fans must be cycled during unoccupied
hours to meet the heating and cooling loads.
Now my query is that if night cycle fan control is kept on Cycle on Any
then it is observed from the hourly reports that chillers are operated
during night time and even on holidays, but this is not the actual case as
chillers (or even the electric heating) won't be on during night hours or

I have checked the schedules and thermostat set points in zones and they
seem to be fine. The temperatures are considered 75.2F and 70F respectively
for cooling and heating in occupied hours and 82F and 64F in unoccupied

So please let me know if it is correct that chillers are cycling on during
unoccupied hours?  If no, then what should be done to operate them only in
occupied hours.

Note: I tried to give on/off schedule to chilled water loop but it gives
unreasonable amount of unmet hours.

Thanks in advance.
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