Sequence of Operation
Constant Volume
The following conditions must be met in order for Economizer Loading to function:
•The outdoor air temperature must be greater than the return air temperature.
•Economizer must be installed but not active.
•A call for first stage compressor operation only
•The unit must be configured as a Constant Volume unit.
•The unit must be in an occupied or unoccupied cooling mode.
The sequence of operation is as follows:
•When the supply air temperature is 0.1° F less than the “SUPPLY AIR TEMP LIMIT COOLING SETPOINT” the economizer damper will start to open.
•If the economizer damper opens 100% and the supply air temperature is still 0.1° F less than the “SUPPLY AIR TEMP LIMIT COOLING SETPOINT” the Simplicity Control will turn off the compressor per the Excessive SAT sequence and close the economizer damper to its minimum position.
•When the supply air temperature is between
“SUPPLY AIR TEMP LIMIT COOLING SETPOINT” and the “SUPPLY AIR TEMP LIMIT COOLING SETPOINT” plus 5.0° F the economizer damper movement will stop and maintain the current position.
•When the supply air temperature is equal to 5.1° F or more above the “SUPPLY AIR TEMP LIMIT COOLING SETPOINT” the economizer damper will close back to its minimum position.
Variable Air Volume
The following conditions must be met in order for Economizer Loading to function:
•The outdoor air temperature must be greater than the return air temperature.
•Economizer must be installed but not active.
•A call for first stage compressor operation only.
FORM
•The unit must be configured as a Variable Air Volume unit.
•The unit must be in an occupied or unoccupied cooling mode.
The sequence of operation is as follows:
•When the supply air temperature is 5.1° F less than the “VAV COOLING SUPPLY TEMP UP- PER SAT SETPOINT” or “VAV COOLING SUPPLY AIR TEMP LOWER SETPOINT” the economizer damper will start to open.
•If the economizer damper opens 100% and the supply air temperature is still 5.1° F less than the “VAV COOLING SUPPLY TEMP UPPER SAT SETPOINT” or “VAV COOLING SUPPLY AIR TEMP LOWER SETPOINT” the Simplicity Control will turn off the compressor close the economizer damper to its minimum position.
•When the supply air temperature is between
“VAV COOLING SUPPLY TEMP UPPER SAT SETPOINT” and the “VAV COOLING SUPPLY TEMP UPPER SAT SETPOINT” plus 5.0° F the economizer damper movement will stop and maintain the current position.
•When the supply air temperature is between
“VAV COOLING SUPPLY TEMP LOWER SAT SETPOINT” and the “VAV COOLING SUPPLY TEMP LOWER SAT SETPOINT” plus 7.0° F the economizer damper movement will stop and maintain the current position.
•When the supply air temperature is equal to 5.1° F or more above the “VAV COOLING SUPPLY TEMP UPPER SAT SETPOINT” and 5 minutes has expired since the economizer damper started to open, the economizer damper will close back to its minimum position and a second compressor will come on.
•When the supply air temperature is equal to 7.1° F or more above the “VAV COOLING SUPPLY TEMP LOWER SAT SETPOINT” and 5 minutes has expired since the economizer damper started to open, the economizer damper will close back to its minimum position and a second compressor will come on.
80 | JOHNSON CONTROLS |
