York YPAL 051, YPAL 061, YPAL 050, YPAL 060 manual Criteria for Operation, PRE-OCCUPANCY Purge

Sequence of Operation

“BUILDING STATIC PRESSURE SENSOR INSTALLED” – must be turned on using Parameter 85 under the PROGRAM key on the Simplicity Elite control board or under the EQUIPMENT INSTALLATION tab in the Simplicity PC software package.

“BUILDING PRESSURE SETPOINT” must be programmed using Parameter 31 under the PROGRAM key on the Simplicity Elite control board or under the ECONOMIZER/EXHAUST tab in the Simplicity PC software package.

“EXHAUST VFD INSTALLED” must be turned on using Parameter 45 under the PROGRAM key on the Simplicity Elite control board or under the ECONOMIZER/EXHAUST tab in the Simplicity PC software package.

Sequence of Operation

When the building static pressure is 0.025” WC or more above the “BUILDING PRESSURE SETPOINT” the Simplicity Elite control sends a 2 to 10 volt DC signal to Exhaust Fan VFD, the output is at the “EXD+” and “EXD-“ terminals at the P14 connector, and enables the VFD operation through the output at the “EXH” terminal of the P13 connector. When the exhaust fan first comes on it will operate at the “Output Frequency Low Limit” that is programmed into the Exhaust Van VFD, regardless of the voltage output from the Simplicity Elite control.

When the building static pressure is 0.025” WC or more below the “BUILDING PRESSURE SETPOINT” the Simplicity Elite control lowers the 2 – 10 volt DC output to the Exhaust Fan VFD. When the output is equal to or below 2 volts, the Exhaust Fan VFD enable input is removed.

PRE-OCCUPANCY PURGE

This feature allows the blower to come on and the economizer damper to open during the unoccupied period to purge the air within the conditioned space.

In order to use this feature the following parameters must be programmed:

FORM 100.50-NOM6 (1207)

“PRE-OCCUPANCY PURGE ENABLE” – must be enabled using the SYSTEM OPTIONS tab in the Simplicity PC software package.

“PRE-OCCUPANCY PURGE TIME (hours of day)”

–must be programmed using the SYSTEM OPTIONS tab in the Simplicity PC software package.

“PRE-OCCUPANCY PURGE TIME (minutes of day)”

–must be programmed using the SYSTEM OPTIONS tab in the Simplicity PC software package.

Criteria for Operation

•The feature will only work when the internal scheduling feature is being used to determine occupied and unoccupied periods.

•The feature will only work on a day that has a occupied period scheduled.

Sequence of Operation

•The programmed “PRE-OCCUPANCY PURGE TIME” is length of the pre-purge prior to the start of the occupancy period. For example if the “PRE-OCCUPANCY PURGE TIME (hours of day)” is set for 1, the “PRE-OCCUPANCY PURGE TIME (minutes of day)” is set to 30 and the occupancy start time is 8:00 AM pre-purge would start at 6:30 AM and operate until 8:00 AM.

•While in the pre-purge mode the Simplicity Elite control will turn on the fan and modulate the outdoor air damper to 100% as long as the supply air temperature is between 45.0° F and 90.0° F.

•If the supply air temperature drops below 45.0° F the control will modulate the outdoor air damper closed until the supply air temperature rises above 50.0° F.

•If the supply air temperature rises above 90.0° F the control will modulate the outdoor air damper closed unit the supply air temperature falls below 85.0° F.

94 JOHNSON CONTROLS