Supply Duct Pressure Control Algorithm; Morning Warm Up / Vav Occupied Heating Control Algorithm; Sat Control Band; Weekly Schedule - York MILLENIUM SIMPLICITY ELITE Series Technical Application And Programming Manual

351579-YTS-B-0608
free cooling is available (economizer operation) and the other
one for mechanical cooling only. First, when free cooling is
available ("economizer suitable"), the SAT control algorithm is
as described in the Economizer Operation section later in this
document, except the programmed Economizer First Stage
Setpoint and Economizer Second Stage Setpoint are replaced
by the programmed VAV Upper Cooling SAT Setpoint and VAV
Lower Cooling SAT Setpoint.
When free cooling is not available, the SAT control is performed
by the following control algorithm: Minimum compressor off
times (ASCD) of 5 minutes and minimum on times of one to ten
minutes [default is three] are maintained and the cycling rate of
the compressors will not exceed maximum 6 cycles/hour. The
SAT is controlled in a ±5 °F band around the active SAT
setpoint. A compressor is allowed to turn on only if the current
SAT minus the Predicted SAT Drop is more than 5 °F.

SUPPLY DUCT PRESSURE CONTROL ALGORITHM

The Supply Duct pressure is controlled to a specified setpoint (see
paragraph Duct Pressure Setpoint, section Option Operation
earlier in this document). An appropriate closed loop control PI
algorithm is used to control the supply duct static pressure by
modulating Inlet Guide Vanes, or the supply fan VFD.
MORNING WARM UP / VAV OCCUPIED HEATING
CONTROL ALGORITHM
STARTING MORNING WARM UP
Non-networked systems: The MWU (Morning Warm Up) option
is enabled by setting the option parameter and establishing a
start and end Occupied time period in the control's Occupied 1

weekly schedule.

MWU (Morning Warm Up) is initiated upon all transitions from
Unoccupied to Occupied mode. The system clock is used to
identify, for the Morning Warm Up, a 1 hour period before actual
occupancy begins (also see Intelli-Start). If the MWU option is
disabled, the occupancies should be scheduled at their regular
time.
An Occupied Override signal will initiate a warm up of up to two
hours (the setpoint value of the Unoccupied Override Time
Period). It is important to note that the unit is still operating in an
34
Unoccupied mode for the first hour after the occupied Override
input is turned on. Reference the Weekly and Holiday Schedule,
Tables 11 and 12.
Figure 7: SAT Control Band
MORNING WARM UP / VAV OCCUPIED HEATING FUNCTION
Morning Warm Up controls the RAT to a preprogrammed
Morning Warm Up RAT Setpoint. An appropriate closed loop
control algorithm is used to control heat stages to accomplish
this. The algorithm uses a dead band (i.e. control RAT between
the MWU RAT Setpoint and two degrees below the setpoint).
Table 11: Weekly Schedule
Times Mon Tues
Occupied 1 00:00 00:00 00:00 00:00 00:00 00:00 00:00
Unoccupied 1 00:00 00:00 00:00 00:00 00:00 00:00 00:00
Occupied 2 00:00 00:00 00:00 00:00 00:00 00:00 00:00
Unoccupied 2 00:00 00:00 00:00 00:00 00:00 00:00 00:00
HOLIDAY SCHEDULE
• If the Start Time is programmed to zero, the default is all day.
• The Number of Days will be programmed from 0-99.
• The Start Date is programmed by Month-Day-Year.
• When the Start Date is 00-00-0000, that Holiday is ignored.
• When the Time is 00:00, the Time is equal to 12:00 a.m.,
the beginning of the day.
Stage Up If SAT is Above Setpoint
0
By + 5.0 F, or More, For 5 Minutes
0
+ 5.0 F
Active SAT Setpoint
0
- 5.0 F
Stage Down If SAT is Above Setpoint
0
By - 5.0 F, or More, For 5 Minutes
Wed Thu Fri Sat
Johnson Controls Unitary Products
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