York YPAL 051 User Manual
68
JOHNSON CONTROLS
FORM 100.50-NOM6 (1207)
Sequence of Operation
The Simplicity Control will stage off the heat as
follows:
follows:
•
When the return air temperature is 2.4° F below
the “CV OCCUPIED HEATING” or “CV UN-
OCCUPIED HEATING SETPOINT” the third
stage of heating will turn off.
OCCUPIED HEATING SETPOINT” the third
stage of heating will turn off.
•
When the return air temperature is 1.9° F below
the “CV OCCUPIED HEATING” or “CV UN-
OCCUPIED HEATING SETPOINT” the second
stage of heat will turn off.
OCCUPIED HEATING SETPOINT” the second
stage of heat will turn off.
•
When the return air temperature is 0.1° F above
the “CV OCCUPIED HEATING” or “CV UN-
OCCUPIED HEATING SETPOINT” the fi rst
stage of heating will turn off.
OCCUPIED HEATING SETPOINT” the fi rst
stage of heating will turn off.
The Simplicity Control has the following heating timing
functions:
functions:
•
A minimum off time of 2 minutes.
•
A minimum on time of 3 minutes.
•
There is a 30 second time delay between stag-
es.
VARIABLE AIR VOLUME (VAV)
A Variable Air Volume (VAV) unit can be controlled
by four methods:
by four methods:
•
Stage
thermostat
•
Communicated
Space
Temperature
•
Hardwired
Space
Temperature
•
Stand
Alone
-
Return
Air
Temperature
Cooling - Occupied with Thermostat
The following System Parameters must be programmed
through the Simplicity Control for VAV operation:
through the Simplicity Control for VAV operation:
•
“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.
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.
PROGRAM key on the Simplicity control board
or under the COOLING SETUP tab in the Sim-
plicity PC software package.
The Simplicity Control initiates compressor operation
as follows:
as follows:
•
The Simplicity Control will turn compressors on
and off based of the difference between the sup-
ply air temperature and the cooling set point.
ply air temperature and the cooling set point.
•
With no thermostat call or a Y1 first stage
call the Simplicity Control will control to the
“VAV COOLING SUPPLY AIR TEMP UPPER
SETPOINT”. The Y1 input is not required to
initiate compressor operation.
“VAV COOLING SUPPLY AIR TEMP UPPER
SETPOINT”. The Y1 input is not required to
initiate compressor operation.
•
When there is a Y2, Y3, or Y4 call from the
thermostat the Simplicity Control will control to
the “VAV COOLING SUPPLY TEMP LOWER
SETPOINT”.
the “VAV COOLING SUPPLY TEMP LOWER
SETPOINT”.
•
The control uses a 5-degree dead band around
the cooling “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”.
•
When the supply air temperature is 5.0° F
or more above the cooling “VAV COOLING
SUPPLY TEMP UPPER SAT SETPOINT” or
“VAV COOLING SUPPLY AIR TEMP LOWER
SETPOINT” the Simplicity Control will energize
the fi rst compressor.
SUPPLY TEMP UPPER SAT SETPOINT” or
“VAV COOLING SUPPLY AIR TEMP LOWER
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 on if both of
the following criteria are met:
– The supply air temperature is still 5.0° F or
more above the “VAV COOLING SUPPLY
TEMP UPPER SAT SETPOINT” or “VAV
COOLING SUPPLY AIR TEMP LOWER
SETPOINT”.
TEMP UPPER SAT SETPOINT” or “VAV
COOLING SUPPLY AIR TEMP LOWER
SETPOINT”.