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5587001-YSG-A-520 | Start-Up & Operation Guide
Unit Type
The rooftop unit can be ordered in one of the two avail-
able unit configurations:
• Multi zone variable air volume (MZVAV)
• Single zone variable air volume (SZVAV).
Both unit configurations have specific sequences that
operate differently from each other.
MZVAV is the default unit type. SZVAV must be user
enabled in the Commissioning > Standard > SZVAV En-
abled menu.
Occupancy Mode
• The rooftop units can operate in the following oc-
cupancy modes
• Occupied (OCC)
• Unoccupied (UNOCC)
• Morning warm-up/cool down
• Coast
• There are three source of occupancy available
when the occupancy mode is set to external. A
command of occupied on any of the following in-
puts results in occupied operation
• From a BAS
• Tenant override through a zone sensor
• Hard wired input
• When the occupancy mode is set to schedule, the
occupancy is determined by the internal schedule
of the control
Morning Warm-up/Cool Down
External Mode
With a binary input occupied command, the supply fan
turns on for a 5 minute stabilization period, and the oper-
ating space temperature is compared to morning warm-
up and morning cool down setpoints.
When the operational zone temperature is equal to
or below the morning warm-up return air temperature
(RAT) setpoint, heating operates for at least 5 minutes. If
the operational zone temperature is above the morning
warm-up setpoint, the control goes into occupied mode.
Heating runs until 5 minutes pass and the operational
zone temperature is above the morning warm-up set-
point or the early start period expires. The control goes
into occupied mode thereafter.
38
When the operational zone temperature is equal to or
above the morning cool down RAT setpoint, cooling op-
erates for at least 5 minutes. When the operational zone
temperature is below the morning cool down setpoint,
the control goes into occupied mode. Cooling runs until
5 minutes pass and the operational zone temperature is
below the morning cool down setpoint or the early start
period expires. The control goes into occupied mode
thereafter.
Optimal Start
Historical data, operational zone temperature, OCC set-
point, and OAT determine when optimal start begins.
The optimal start time is always within the same cal-
endar day. The control uses the occupied heating and
occupied cooling setpoints to determine when the de-
mand is satisfied. The control goes into occupied mode
thereafter.
Schedule
At the early start period prior to the scheduled occupan-
cy, the supply fan turns on for a 5 minute stabilization pe-
riod, and the operating space temperature is compared
to morning warm-up and morning cool down setpoints.
When the operational zone temperature is equal to or
below the morning warm-up RAT setpoint, heating oper-
ates for at least 5 minutes. If the operational zone tem-
perature is above the morning warm-up setpoint, the
control goes into occupied mode. Heating runs until 5
minutes pass and the operational zone temperature is
above the morning warm-up setpoint or the early start
period expires. The control goes into occupied mode
thereafter.
When the operational zone temperature is equal to or
above the morning cool down RAT setpoint, cooling op-
erates for at least 5 minutes. When the operational zone
temperature is below the morning cool down setpoint,
the control goes into occupied mode. Cooling runs until
5 minutes pass and the operational zone temperature is
below the morning cool down setpoint or the early start
period expires. The control goes into occupied mode
thereafter.
Coast
The coast sequence allows the unit to raise or lower the
active cooling or heating SPs 2 hours (user adjustable)
prior to the transition from OCC to UNOCC.
This sequence allows for added energy conservation
from the unit.
When coast is user enabled, the unit controller raises
the active cooling setpoint 1.0°F per hour or lowers the
active heating setpoint 1.0°F per hour (user adjustable).
YORK
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