York YPAL 051 User Manual
70
JOHNSON CONTROLS
FORM 100.50-NOM6 (1207)
Sequence of Operation
•
When the supply air temperature is 5.0° F or more
above the cooling “VAV UPPER COOLING SAT
SETPOINT” or “VAV LOWER COOLING SAT
SETPOINT” the Simplicity Control will energize
the fi rst compressor.
SETPOINT” or “VAV LOWER COOLING SAT
SETPOINT” the Simplicity Control will energize
the fi rst compressor.
•
The control records the supply air temperature
right before the compressor is turned on and
compares it to the supply air temperature after 5
minutes of operation.
compares it to the supply air temperature after 5
minutes of operation.
•
A second compressor will be turned if both of
the following criteria are met:
– The supply air temperature is still 5.0° F or
more, greater then the “VAV UPPER COOL-
ING SAT SETPOINT” or “VAV LOWER
COOLING SAT SETPOINT”.
ING SAT SETPOINT” or “VAV LOWER
COOLING SAT SETPOINT”.
– The Simplicity Control uses the temperature
difference calculated when the fi rst compres-
sor was turned on to verify the supply air tem-
perature will not drop 5.0° F or more below
the cooling “VAV UPPER COOLING SAT
SETPOINT” or “VAV LOWER COOLING
SAT SETPOINT”. If turning on a compressor
would result in the specifi ed drop in supply
air temperature, the second compressor will
not be turned on.
sor was turned on to verify the supply air tem-
perature will not drop 5.0° F or more below
the cooling “VAV UPPER COOLING SAT
SETPOINT” or “VAV LOWER COOLING
SAT SETPOINT”. If turning on a compressor
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 turn off compressor operation
as follows:
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”.
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 a Hard Wired or Com-
municated Space Sensor
municated Space Sensor
The Simplicity Control cannot operate unoccupied
cooling with this method of control.
cooling with this method of control.
Heating – Occupied with a Hard Wired or Com-
municated Space Sensor
municated Space Sensor
The following parameter must be programmed into the
Simplicity Control:
Simplicity Control:
•
“VAV OCCUPIED HEATING ENABLED” – This
must be turned on using Parameter 26 under the
PROGRAM key on the Simplicity control board
or under the HEATING SETUP tab in the Sim-
plicity PC software package.
PROGRAM key on the Simplicity control board
or under the HEATING SETUP tab in the Sim-
plicity PC software package.
•
“MORNING WARM-UP/ VAV RETURN AIR
TEMP SETPOINT” – using Parameter 29 under
the PROGRAM key on the Simplicity control
board or under the HEATING SETUP tab in the
Simplicity PC software package.
the PROGRAM key on the Simplicity control
board or under the HEATING SETUP tab in the
Simplicity PC software package.
•
“VAV OCCUPIED HEATING SETPOINT” – us-
ing Parameter 27 under the PROGRAM key on
the Simplicity control board or under the HEAT-
ING SETUP tab in the Simplicity PC software
package.
the Simplicity control board or under the HEAT-
ING SETUP tab in the Simplicity PC software
package.
The unit will initiate Occupied Heating when the
following criteria is met:
following criteria is met:
•
The space temperature is 2.0° F less than the
“VAV OCCUPIED HEATING SETPOINT”.
•
The return air temperature is 0.1° F below the
“MORNING WARM UP / VAV RETURN AIR
TEMP SETPOINT”.
TEMP SETPOINT”.
The unit will terminate Occupied Heating when the:
•
The return air temperature is equal to the
“MORNING WARM UP RAT SETPOINT”.
The “VAV OCCUPIED HEATING SETPOINT” should
always be set below the “MORNING WARM UP RAT
SETPOINT”.
always be set below the “MORNING WARM UP RAT
SETPOINT”.
Heating – Unoccupied with a Hard Wired or Com-
municated Space Sensor
municated Space Sensor
The Simplicity Control cannot operate unoccupied
heating with this method of control.
heating with this method of control.