York MILLENNIUM YCUL0016SC, Assembly, Installation, Operation & Maintenance

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YORK INTERNATIONAL
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This display shows suction and discharge pressures on
the respective system. If the optional discharge trans-
ducer is not installed, the discharge pressure would dis-
play 0 PSIG (0 BARG). The discharge pressure trans-
ducer is optional on all models
Some models come factory wired with a low pressure
switch in place of the suction transducer. In this case,
the suction pressure would only be displayed as the
maximum suction pressure reading of >200 PSIG (13.79
BARG) when closed, or < 0 PSIG (0 BARG) when open.
The suction transducer is standard on YCUL0076 -
YCUL0090 only.
The minimum limits for the display are:
• Suction Pressure: 0 PSIG (0 BARG)
• Discharge Pressure: 0 PSIG (0 BARG)
The maximum limits for the display are:
• Suction Pressure: 200 PSIG (13.79 BARG)
• Discharge Pressure: 400 PSIG (27.58 BARG)
This message shows the suction line temperature of the
respective refrigerant system. The minimum limit on
the display for these parameters is 9.2°F (-12.7°C).
The maximum limit on the display is 85.4°F (29.7°C).
The temperature sensors for this function are optional
on all models.
The first display shows accumulated running hours of
each compressor for the specific system. The second
message shows the number of starts for each compres-
sor on each system.
S Y S X S P = 7 2 . 1 P S I G
D P = 2 2 7 . 0 P S I G
S Y S X S U C T I O N T E M P
= 7 3. 6° F
S Y S X H O U R S 1 = X X X X X
2 = X X X X X, 3 = X X X X X
C O O L I N G D E M A N D
2 O F 8 S T E P S
L E A D S Y S T E M I S
S Y S T E M N U M B E R 2
L O A D T I M E R = 5 8 S E C
U N L O A D T I M E R = 0 S E C
S Y S X S T A R T S 1 = X X X X X
2 = X X X X X, 3 = X X X X X
Unit Controls
(Only displayed when control mode programmed for
Discharge Air Temperature)
This display of the load and unload timers indicate the
time in seconds until the unit can load or unload.
Whether the systems loads or unloads is determined by
how far the actual liquid temperature is from setpoint.
A detailed description of unit loading and unloading is
covered under the topic of Capacity Control.
(Only displayed when control mode programmed for
Discharge Air Temperature)
The display of COOLING DEMAND indicates the cur-
rent “step” in the capacity control scheme. The number
of available steps are determined by how many com-
pressors are in the unit. In the above display, the “2”
does not mean that two compressor are running but only
indicates that the capacity control scheme is on step 2
of 8. Capacity Control is covered in more detail in this
publication which provides specific information on
compressor staging.
(Only displayed when control mode programmed for
Discharge Air Temperature)
This display indicates the current LEAD system. In this
example system 2 is the LEAD system, making system
1 the LAG compressor. The LEAD system can be manu-
ally selected or automatic. Refer to the programming
under the “Options” key.
A unit utilizing hot gas bypass should
be programmed for MANUAL with
system 1 as the lead system. Failure to
do so will prevent hot gas operation if
system 2 switches to the lead system
when programmed for AUTOMATIC
LEAD/LAG.