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1. The slide is prevented from closing further, and the
status line on the CVC indicates the reason for the
override.
2. The slide valve is opened until the condition decreases
to below the first step set point. Then the slide valve is
normal capacity control. Whenever the motor current
demand limit set point (ACTIVE DEMAND LIMIT) is
reached, it activates a capacity override, again, with a
2-step process. Exceeding 110% of the rated load amps
for more than 30 seconds will initiate a safety
shutdown.
Low Discharge Temperature Control —
Low dis-
charge superheat is protective limit for R-22, Frame 1 and 2 TC
compressor chillers only. Monitoring of discharge superheat is
initiated 30 minutes after a completed start-up. If the discharge
superheat, calculated as COMPRESSOR DISCHARGE TEM-
PERATURE – CONDENSER REFRIGERANT TEMPERA-
TURE, falls below 20 F (11.1 C) for 10 consecutive minutes, a
“low discharge superheat” non-recycle shutdown alarm 240,
will occur.
Oil Sump Temperature Control TC (Frame 1
and 2) Chillers Only —
The oil sump temperature con-
trol is regulated by the PIC II using the oil heater relay when
the chiller is shut down. The oil heater relay is energized when-
ever the chiller compressor is off, and the oil sump temperature
is less than 140 F (60 C) or sump temperature is less than the
cooler refrigerant temperature plus 53 F (29.4 C). The heater is
then turned off when the oil sump temperature is:
1. More than 150 F (71 C).
2. The sump temperature is more than 142 F (61.1 C) and
more than the cooler refrigerant temperature plus 55 F
(12.8 C). (The heater is always off during start-up or
when the compressor is running.)
Table 4 — Protective Safety Limits and Control Settings
All oil filter isolation valves should always be left open,
except when changing the oil or oil filter as defined in
Changing Oil and Oil Filter section, page 73.
MONITORED PARAMETER
LIMIT
APPLICABLE COMMENTS
TEMPERATURE SENSOR OUT OF RANGE
–40 to 245 F (–40 to 118.3 C)
Must be outside range for 2 seconds.
PRESSURE TRANSDUCERS OUT OF RANGE
0.06 to 0.98 Voltage Ratio
Must be outside range for 3 seconds.
Ratio = Input Voltage ÷ Voltage Reference
COMPRESSOR DISCHARGE TEMPERATURE
>220 F (104.4 C)
Preset, alert setting configurable.
MOTOR WINDING TEMPERATURE
>220 F (104.4 C)
Preset, alert setting configurable.
LOW DISCHARGE SUPERHEAT
Oil sump temp — condenser refrigerant
temp is less than 20 F (11.1 C). Only appli-
cable to TC (frame 1 and 2) chillers.
Preset, monitored 30 minutes after start-up
completion must be outside range for
10 consecutive minutes.
OIL PRESSURE
— Dirty Oil Filter
Oil pressure transducer less than con-
denser pressure — oil filter pressure alert
starting 40 seconds after motor current
> 10% and oil pressure verified
Must be outside range for 3 seconds; oil
pressure alert setting configurable from 1 to
15 psi (6.9 to 103 kPa) on SETUP 1 table.
Oil pressure transducer less than con-
denser pressure — 110 psi (758 kPa)
starting 40 seconds after motor current
> 10% and oil pressure verified
Must be outside range for 3 seconds.
— Low Oil Pressure
<Required oil pressure starting 120 sec-
onds after motor current > 10%
Minimum required oil pressure based on
system pressure ratio is between 7 psi
(48 kPa) and 20 psi (137.9 kPa)
OIL LEVEL
Discrete
Preset: must be outside range for
15 seconds.
EVAPORATOR REFRIGERANT
TEMPERATURE
<33 F (FOR WATER CHILLING) (0.6°C)
Preset, configurable chilled medium for
water (SETUP1 table).
<EVAP REFRIG TRIPPOINT (set point
adjustable from 0 to 40 F [–18 to 4 C] for
brine chilling)
Configure chilled medium for brine
(SETUP1 table). Adjust EVAP REFRIG
TRIPPOINT for proper cutout.
TRANSDUCER VOLTAGE
<4.5 vdc> 5.5 vdc
Preset
CONDENSER PRESSURE
— Switch
263 ± 5 psig (1813 ± 34 kPa), reset at
180 ± 7 psig (1241 ± 48 kPa)
Preset
— Control
260 psig (1793 kPa)
Preset
LINE VOLTAGE
— High
>150% for 1 second or >120% for
10 seconds
Preset, based on transformed line voltage
to ISM. Also monitored at CVC and CCM
power input.
— Low
<85% for 10 seconds or
≤
80 for 5 seconds
or <75% for 1 second
— Single-Cycle
<50% for one cycle
COMPRESSOR MOTOR LOAD
>110% for 30 seconds
Preset
<5% with compressor running
Preset
<5% with compressor off
Preset
STARTER ACCELERATION TIME
(Determined by inrush current going below
100% compressor motor load)
>45 seconds
For chillers with reduced voltage mechanical
and solid-state starters.
>10 seconds
For chillers with full voltage starters
(Configures on ISM_CONFIG table).
STARTER TRANSITION
>20 seconds
Reduced voltage starters only.
CONDENSER FREEZE PROTECTION
Energizes condenser pump relay if
condenser refrigerant temperature or
entering water temperature is below the
configured condenser freeze point temper-
ature. Deenergizes when the temperature
is 5 F (3 C) above condenser freeze point
temperature.
CONDENSER FREEZE POINT configured
in SETUP1 table with a default setting of
34 F (1 C).
Содержание 23XL
Страница 18: ...18 Fig 15 Control Panel Fig 16 Power Panel ...
Страница 51: ...51 Fig 31 23XL Leak Test Procedure ...
Страница 52: ...52 Fig 32 Typical Optional Pumpout System Piping Schematic with Storage Tank TC Frame 1 and 2 Chillers ...
Страница 53: ...53 Fig 33 Typical Optional Pumpout System Piping Schematic With Storage Tank TD Frame 4 Chillers ...
Страница 54: ...54 Fig 34 Typical Optional Pumpout System Piping Schematic Without Storage Tank TC Frame 1 and 2 Chillers ...
Страница 55: ...55 Fig 35 Typical Optional Pumpout System Piping Schematic Without Storage Tank TD Frame 4 Chillers ...
Страница 99: ...99 Fig 49 Benshaw Inc Solid State Unit Mounted Starter Wiring Schematic Low Voltage ...