York YPAL 060 User Manual

JOHNSON CONTROLS

FORM 100.50-NOM6 (1207)

•

  When the space temperature is equal to or greater 

than 2.0° F above the “VAV SUPPLY AIR TEMP 
RESET SETPOINT” the Simplicity Control will 
use the “VAV COOLING SUPPLY AIR TEMP 
LOWER   SETPOINT”.

The Simplicity Control will use outdoor air without 
compressor operation when the following is true:

•

  Economizer is active.

•

  The outdoor air temperature is equal to or less 

then the economizer set point.

The Simplicity Control will use outdoor air with 
compressor operation when the following is true:

•

  Economizer is active.

•

  The outdoor air temperature is above the econo-

mizer set point. 

When outdoor air and compressor operation is available 
the compressors operation will be controlled as 
follows:

•

  If the supply air temperature is 5.1° F or more 

above the economizer set point and the Econo-
mizer PI output is saturated (100%) the Simplic-
ity Control will turn on a compressor and start a 
3 minute timer.

•

  If after 3-minutes the temperature is still 5.1° F 

above the economizer set point and the Econo-
mizer PI output is saturated (100%) the Simplic-
ity Control will bring on a second compressor and 
start a three minute timer.

•

  This sequence would continue until all the com-

pressors on.

•

  If after the 3-minute timing the supply air tem-

perature is within +/- 5.0° F of the economizer 
set point no change will be made to the number 
of compressors operating.

•

  If after the 3-minute timing the supply air tem-

perature is 5.1° F or more below the economizer 
set point and the Economizer PI output is low 
(dampers at the minimum position setting) the 
Simplicity Control will turn off a compressor.

•

  As long as the supply air temperature is 5.1° F 

below the economizer set point and the Econo-
mizer PI output is low (damper at minimum 
position setting) the Simplicity Control will turn 
off compressors every 3-minutes until all the 
compressor have been turned off.

The Simplicity Control uses a proportional and integral 
logic (PI loop) to control the operation of the damper 
actuator.  The Simplicity Control monitors the change 
in the supply air temperature to the economizer set point 
verses changes to the output to the damper actuator.  
When the supply air temperature is more then 2.0° F 
from the economizer set point the Simplicity Control 
will change the output to the economizer damper 1% 
every 2 seconds.  If the supply air temperature is within 
+/- 2.0° F of the economizer set point the Simplicity 
Control will change the output to the economizer 
damper 0.5% every 2 seconds.

Economizer Loading is a programmable option that 
can be used to place an artifi cial load on the unit to 
prevent cycling a compressor off when the supply 
air temperature approaches the “SUPPLY AIR TEMP 
LIMIT COOLING SETPOINT”. 

T h e   f o l l o w i n g   S y s t e m   P a r a m e t e r   m u s t   b e 
programmed:

“ECONOMIZER LOADING ENABLE” – must be 
enabled under the COOLING SETUP tab in the 
Simplicity PC software package.

“SUPPLY AIR TEMP LIMIT COOLING SETPOINT” 
must be programmed using the COOLING SETUP tab 
in the Simplicity PC software package.

“SUPPLY AIR TEMP LIMIT FOR COOLING” must 
be enabled using the COOLING SETUP tab in the 
Simplicity PC software package.