S | Y S | 1 | S P | = | 7 2 | . 1 | P S I G | ||||
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| D P | = 2 | 2 | 7 | . 0 | P S I G | |||
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S | Y S | 2 | S P | = | 7 3 | . | 6 | P S | I | G | |
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| D P | = 2 | 1 | 9 | . | 8 | P S | I | G |
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These displays show suction and discharge pressures for systems 1 & 2. The discharge pressure transducer is optional on all models
If the optional discharge transducer is not installed, the discharge pressure would display 0 PSIG (0 barg).
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 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)
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
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
The above two messages will appear sequentially for each system. The first display shows accumulated run- ning hours of each compressor for the specific system. The second message shows the number of starts for each compressor on each system.
FORM
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 | ||
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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.
C O O L I N G D E M A N D
2 O F 8 S T E P S
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.
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
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.
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YORK INTERNATIONAL | 67 |
