York YCRJ45E00, Установка, эксплуатация и обслуживание

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YORK INTERNATIONAL
CONDENSER WATER READOUT OPTION
This option provides a micropanel display of entering and
leaving condenser water temperature.
Temperature sensors, wiring, connectors, and pins are
supplied to field wire the sensors into the J16 plug on
the Microprocessor board. A label is also supplied to
indicate the key on the keypad which allows viewing of
these temperatures. This key is located directly below
the “Options” key.
Temperature wells are field suppled according to the size
of the piping.
Shown below is a sample display
HOT GAS BYPASS (LOADMINDER) OPTION
General
The Hot Gas Bypass Option is available as a factory
installed option to prevent compressor cycling and wa-
ter temperature fluctuation at low load. This is ac-
complished by providing further capacity reduction be-
low the last step of compressor cylinder unloading by
introducing an artificial load to the cooler, which keeps
the compressor on the line. The option will provide hot
gas bypass on both compressors enabling hot gas to be
active regardless of which compressor is in the lead.
NOTE: The microprocessor will only activate the hot gas
on the lead compressor.
“YCR” models with optional Hot Gas Bypass (Load-
minder) require field piping to be completed to the dis-
charge side of the system piping.
The hot gas bypass consists of a pilot operated regu-
lating valve with an integral solenoid. The pilot operated
solenoid is controlled by the microprocessor according
to water temperature. The regulating valve, which be-
comes activated when the solenoid is energized, is con-
trolled by suction pressure to modulate the flow of gas in
a bypass connected from the compressor discharge to
the cooler inlet. The following text will explain how the
hot gas solenoid is activated by the microprocessor in
both return and in leaving water control.
LWT Control Hot Gas Operation
The hot gas solenoid is energized when the leaving wa-
ter temperature falls below the “Target” water temperature,
if the compressor is on its minimum stage of loading.
Hot gas may then be fed according to the suction pres-
sure and the pressure regulating valve setting. Once ac-
tivated, the micro will keep the solenoid energized until
the leaving water temperature rises above the high limit
of the Control Range or until the load becomes so low
that the hot gas can no longer keep temperature within
the control range and the micro turns the compressor
off. Details for setting the pressure regulator follow.
RWT Control Hot Gas Operation
The hot gas solenoid is energized if the compressor is
on its minimum stage of loading and the return water
temperature falls below the following point:
ULCR – CR + CR/20
Where: UCLR = Upper Limit of Control Range
CR = Control Range Differential
Example: In a typical system that requires a 45°F
leaving water temperature, we will have a
10° control range (CR) differential which
gives us an Upper Limit of Control Range
(ULCR) of 55°F. Therefore, plugging the
numbers into the formula:
55 – 10 + (10/20) = 45-1/2°F
The hot gas solenoid will be activated at 45-1/2°F in the
example above and hot gas may then be fed according
to the suction pressure and the pressure regulated valve
setting. Once activated, the micro will keep the solenoid
energized until the return water temperature rises above
the temperature designated by the formula:
ULCR – CR + CR/10
Where: UCLR = Upper Limit of Control Range
CR = Control Range Differential
Example: 55 – 10 + 10/10 = 46°F
If temperature continues to drop while the Hot Gas is
energized, the Hot Gas will be de-energized when the
compressor cycles off on temperature.
Procedure For Setting The Hot Gas Regulator
(Ref. Fig. 31)
1. If desired, set the control panel data to show suction
pressure.
E C O N D W T = 8 5 D E G F
L C O N D W T = 7 5 D E G F