Specifications

73
Table 48 — High-Pressure Switch Settings
If the switch opens during operation, the compressor will be
shut down. The CPM will reset automatically when the switch
closes, however, a manual reset of the control is required to
restart the compressor.
COOLER PROTECTION
Low Water Temperature
— Microprocessor is programmed
to shut the chiller down if the leaving fluid temperature drops
below 34 F (1.1 C) for water or more than 8 F (4.4 C) below
set point for Fluid Type = brine. When the fluid temperature
rises 6 F (3.3 C) above the leaving fluid set point, the safety
resets and the chiller restarts. Reset is automatic as long as this
is the first occurrence of the day.
Relief Devices — Fusible plugs are located in each cir-
cuit between the condenser and the liquid line shutoff valve.
PRESSURE RELIEF VALVES — Valves are installed in each
circuit and are located on all coolers and condensers. These
valves are designed to relieve if an abnormal pressure condition
arises. Relief valves on all coolers relieve at 220 psi (1517 kPa).
These valves should not be capped. If a valve relieves, it should
be replaced. If the valve is not replaced, it may relieve at a lower
pressure, or leak due to trapped dirt from the system which may
prevent resealing. Valves on standard condensers relieve at
220 psi (1517 kPa). Valves on high condensing and heat
machine units relieve at 300 psi (2068 kPa).
Dual pressure relief valves are mounted on the three-way
valves in some locations to allow testing and repair without
transferring the refrigerant charge. Three-way valve shafts
should be turned either fully clockwise or fully counterclock-
wise so only one relief valve is exposed to refrigerant pressure
at a time.
Pressure relief valves located on shells have
3
/
4
-in. NPT
connections for relief. Some local building codes require that
relieved gases be exhausted to a specific location. This connec-
tion allows conformance to this requirement. Refer to Installa-
tion Instructions for details.
INSPECTION AND MAINTENANCE — The relief valves
on this chiller protect the system against the potentially danger-
ous effects of overpressure. To ensure against damage to the
equipment and possible injury to personnel, these devices must
be kept in peak operating condition.
As a minimum, the following maintenance is required:
1. At least once a year, disconnect the vent piping at the
valve outlet. Inspect the vent piping for corrosion, a re-
striction or blockage. If any is found, clean or replace the
affected vent piping.
2. Carefully inspect the valve body and mechanism for any
evidence of internal corrosion or rust, dirt, scale, leakage,
etc. If corrosion or foreign material is found, do not at-
tempt to repair or recondition; replace the valve.
3. If the chiller is installed in a corrosive atmosphere or the
relief valves are vented into a corrosive atmosphere, in-
spect relief valves and piping at more frequent intervals.
MAINTENANCE
Recommended Maintenance Schedule —
The fol-
lowing are only recommended guidelines. Jobsite conditions
may dictate that maintenance schedule is performed more often
than recommended.
Every month:
• Check moisture indicating sight glass for possible refriger-
ant loss and presence of moisture.
Every 3 months:
• Check refrigerant charge.
• Check all refrigerant joints and valves for refrigerant leaks;
repair as necessary.
• Check chilled water and condenser flow switch operation.
• Check oil filter pressure drop.
Every 12 months:
• Check all electrical connections; tighten as necessary.
• Inspect all contactors and relays; replace as necessary.
• Check accuracy of thermistors; replace if greater than ±2° F
(1.2° C) variance from calibrated thermometer.
• Check accuracy of transducers; replace if greater than ±5 psi
(34.47 kPa) variance.
• Check to be sure that the proper concentration of antifreeze
is present in the chilled water and condenser loops, if
applicable.
• Verify that the chilled water loop is properly treated.
• Check refrigerant filter driers for excessive pressure drop;
replace as necessary.
• Check chilled water and condenser strainers, clean as
necessary.
• Perform Service Test to confirm operation of all components.
• Check for excessive cooler approach (Leaving Chilled
Water Temperature – Saturated Suction Temperature) which
may indicate fouling. Clean cooler vessel if necessary.
• Obtain oil analysis; change as necessary.
TROUBLESHOOTING
See Table 49 for an abbreviated list of symptoms, possible
causes and possible remedies.
Alarms and Alerts — The integral control system con-
stantly monitors the unit and generates warnings when abnor-
mal or fault conditions occur. Alarms may cause either a circuit
(Alert) or the whole machine (Alarm) to shut down. Alarms
and Alerts are assigned codes as described in Fig. 58. The
alarm/alert indicator LED on the Navigator™ module is
illuminated when any alarm or alert condition is present. If an
Alert is active, the Alarm Indicator LED will blink. If an Alarm
is active, the Alarm Indicator LED will remain on. Currently
active Alerts and Alarms can be found in (Current Alarm,
ALRM).
30XW UNIT
SWITCH SETTING
psig kPa
STD 217.6 +7.25, –14.5 1500 +50, –100
HIGH COND 275 +
10 1896 + 69
IMPORTANT: If unit is installed in an area where
ambient temperatures fall below 32 F (0° C), a suit-
able corrosion-inhibited antifreeze solution must be
used in the chilled water and condenser water circuit.
Alarm Suffix
Code Number to identify source
Alarm Descriptor
th
.01
Alarm Prefix
A1 – Compressor A1 Failure
B1 – Compressor B1 Failure
Co – Communication Failure
FC – Factory Configuration Error
MC – Master Chiller Configuration Error
P – Process Failure
Pr – Pressure Transducer Failure
Sr – Service Notification
th – Thermistor Failure
Alarm
Fig. 58 — Alarm Description
A30-4847