York YPAL 051 Constant Volume Economizer Set Point, Variable Air Volume Economizer Set Point

Sequence of Operation

“OUTSIDE AIR HUMIDITY SENSOR INSTALLED”

-must be disabled using Parameter 36 under the PROGRAM key on the Simplicity Control board or under the EQUIPMENT INSTALLATION tab in the Simplicity PC software package.

“RETURN AIR HUMIDITY SENSOR INSTALLED”

-must be disabled using Parameter 38 under the PROGRAM key on the Simplicity Control board or under the EQUIPMENT INSTALLATION tab in the Simplicity PC software package.

“THIRD PARTY BAS ECONOMIZER INSTALLED” must be enabled using Parameter 58 under the PROGRAM key on the Simplicity Control board or under the EQUIPMENT INSTALLATION tab in the Simplicity PC software package.

In order to use this feature a 2 to 10 VDC external signal must be sent to the unit through the “BAS ECON +” and “BAS ECON -” connections on the Unit Control board.

Sequence of Operation

The Unit Controller sends the 2 to 10 VDC input signal directly to the analog output terminals “ECO +” and “ECO -” to the damper actuator. A 2 VDC input from the external source will result in a 2 VDC signal to the damper actuator.

If voltage is applied to the “BAS ECON +” and “BAS ECON -” terminals be- fore “THIRD PARTY BAS ECONO- MIZER INSTALLED” is enabled the Unit Controller can be damaged.

Constant Volume Economizer Set Point

The following parameter must be programmed to allow economizer operation:

“ECONOMIZER FIRST STAGE SETPOINT” – must be programmed using Parameter 33 under the PROGRAM key on the Simplicity control board or under the ECONOMIZER/EXHAUST tab in the Simplicity PC software package.

FORM 100.50-NOM6 (1207)

“ECONOMIZER SECOND STAGE SETPOINT”

–must be programmed using Parameter 34 under the PROGRAM key on the Simplicity control board or under the ECONOMIZER/EXHAUST tab in the Simplicity PC software package.

The Simplicity Control will try to modulate the outdoor air damper and the compressors to maintain the supply air temperature to +/- 1.0° F of the following set points based on the method of control:

•With a Y1 input from a thermostat the Simplic- ity Control will use the “ECONOMIZER FIRST STAGE SETPOINT”.

•With a Y2, Y3, or Y4 input from a thermostat the Simplicity Control will use the “ECONOMIZER SECOND STAGE SETPOINT”.

•When the space temperature is 1.5° F to 1.9° F above the “CV OCCUPIED COOLING SETPOINT” or “CV UNOCCUPIED COOLING SETPOINT” the Simplicity Control will use the

“ECONOMIZER FIRST STAGE SETPOINT”.

•When the space temperature is 2.0° F above the “CV OCCUPIED COOLING SETPOINT” or

“CV UNOCCUPIED COOLING SETPOINT” the Simplicity Control will use the “ECONO-

MIZER SECOND STAGE SETPOINT”.

Variable Air Volume Economizer Set Point

The Simplicity Control will try to modulate the outdoor air damper and the compressors to maintain the supply air temperature to +/- 1.0° F of the following set points based on the method of control:

•With a Y1 input from a thermostat the Simplicity Control will use the “VAV COOLING SUPPLY AIR TEMP UPPER SETPOINT”.

•With a Y2, Y3, or Y4 input from a thermostat the Simplicity Control will use the “VAV COOLING SUPPLY AIR TEMP LOWER SETPOINT”.

•When the space temperature is less then 2.0° F above the “VAV SUPPLY AIR TEMP RESET SETPOINT” the Simplicity Control will use the

“VAV COOLING SUPPLY AIR TEMP UPPER SETPOINT”.

78 JOHNSON CONTROLS