York ECO2 YPAL 050 - Manual (Page 69)

69 JOHNSON CONTROLS
FORM 100.50-NOM6 (1207)
5
– The Simplicity Control uses the temperature
difference calculated when the first com-
pressor was turned on to verify the supply
air temperature will not drop 5.0° F or more
below the cooling “VAV COOLING SUPPLY
TEMP UPPER SAT SETPOINT” or “VAV
COOLING SUPPLY AIR TEMP LOWER
SETPOINT”. If turning a compressor on
would result in the specifi ed drop in supply
air temperature, the second compressor will
not be turned on.
•
The same logic will be used to stage on compres-
sor 3 and 4.
The Simplicity Control turns off compressor operation
as follows:
•
The supply air temperature is 5.0° F or more
below the “VAV COOLING SUPPLY TEMP
UPPER SAT SETPOINT” or “VAV COOLING
SUPPLY AIR TEMP LOWER SETPOINT”.
•
It has been more than 5-minutes since the last
compressor was turned on.
•
The compressors will be turned off in the reverse
order they were turned on.
Cooling – Unoccupied with Thermostat
The operation is the same as Occupied Cooling with a
Thermostat except:
•
A Y1 call will energize the supply fan.
•
The Simplicity Control will not bring on compres-
sors until the supply air temperature is 5.0° F or
more above the “VAV COOLING SUPPLY TEMP
UPPER SAT SETPOINT” or “VAV COOLING
SUPPLY AIR TEMP LOWER SETPOINT”.
•
Both of the above criteria must be met before the
Simplicity Control will bring on compressors.
Occupied or Unoccupied Heating with a Thermo-
stat
The following parameter must be programmed through
the Simplicity Control:
•
“VAV OCCUPIED HEATING ENABLED”
– must be turned on using Parameter 26 under
the PROGRAM key on the Simplicity control
board or under the HEATING SETUP tab in the
Simplicity PC software package.
Any W thermostat input will energize all the available
heat stages with a 30 second delay between stages.
Occupied Cooling with Hard Wired or Communi-
cated Space Sensor
The following System Parameters must be programmed
through the Simplicity Control for VAV operation with
a space sensor:
•
“VAV COOLING SUPPLY AIR TEMP UPPER
SETPOINT” – using Parameter 23 under the
PROGRAM key on the Simplicity control board
or under the COOLING SETUP tab in the Sim-
plicity PC software package.
•
“VAV COOLING SUPPLY AIR TEMP LOWER
SETPOINT” – using Parameter 24 under the
PROGRAM key on the Simplicity control board
or under the COOLING SETUP tab in the Sim-
plicity PC software package.
•
“VAV SUPPLY AIR TEMP RESET SETPOINT”
– using Parameter 25 under the PROGRAM
key on the Simplicity control board or under
the COOLING SETUP tab in the Simplicity PC
software package.
The Simplicity Control will control the operation of the
compressors as follows:
•
If the space temperature is 2.0° F or more above the
“VAV SUPPLY AIR TEMP RESET SETPOINT”
the control will use the “VAV COOLING SUPPLY
AIR TEMP LOWER SETPOINT”.
•
If the space temperature is not 2.0° F or more
above the “VAV SUPPLY AIR TEMP RESET
SETPOINT” the control will use the “VAV
COOLING SUPPLY AIR TEMP UPPER
SETPOINT”.
•
If the control is using the “VAV COOLING
SUPPLY AIR TEMP LOWER SETPOINT” per
above the space temperature must be equal to or
less than the “VAV SUPPLY AIR TEMP RESET
SETPOINT” before the control would switch to
the “VAV COOLING SUPPLY AIR TEMP UP-
PER SETPOINT”.
•
The control uses a 5-degree dead band around the
cooling “VAV COOLING SUPPLY AIR TEMP
UPPER SETPOINT” or “VAV COOLING SUP-
PLY AIR TEMP LOWERT SETPOINT”.