Carrier VAV Zone II Installation And Startup Manual page 62

Sequence of operation
COOL
OFF
VAV Zone II Controllers
Installation and Start-up Guide
The zone's local heat has not operated for at least 5 minutes, the current mode is not
Heat, and the SAT is less than 65°F (18.3°).
Terminal airflow is used determine if the primary air source fan is on or off. If the
terminal's Damper Position is greater than 95% and the cfm (liters/second) is less
than 10% of Nominal CFM* (liters/second) at 1" (.249 kpa) Velocity Pressure for 1
minute and the cfm (liters/second) Setpoint is not equal to 0, then the fan is
determined to be off. If cfm (liters/second) is greater than 20% of the Nominal CFM*
(liters/second) at 1" (.249 kpa) Velocity Pressure, or greater than 50% of cfm
(liters/second) Setpoint for 10 seconds (whichever is greater), then the fan is
determined to be on.
Occupied/Unoccupied Min CFM (liters/second) must be set for greater than 10% of
Max Cool cfm (liters/second).
* Shown on Properties page as Manufacturer's specified air flow at 1" water
column: for both English and Metric applications.
English: Use manufacturer's cfm at 1" water column
Metric: Use manufacturer's liters/second at .249 kpa
NOTE A local air source fan mode of OFF usually cannot be detected on series fan
boxes. This is because the terminal's series fan, when operating with the terminal
damper open, usually creates enough primary airflow to prevent the control from
properly detecting that the air source is off.
58
CARRIER CORPORATION ©2019
All rights reserved