Specifications

77
Inspect Relief Valves and Piping — 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. Inspect the relief valves in
accordance with local codes.
At a minimum, the following maintenance is required.
1. At least once a year, disconnect the vent piping at the
valve outlet and carefully inspect the valve body and
mechanism for any evidence of internal corrosion or rust,
dirt, scale, leakage, etc.
2. If corrosion or foreign material is found, do not attempt 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,
make valve inspections at more frequent intervals.
Compressor Bearing Maintenance — The com-
pressor bearings are designed to last for the life of the chiller.
The key to good bearing maintenance is proper lubrication.
Use the proper grade of oil, maintained at recommended level,
temperature, and pressure. Inspect the lubrication system
regularly and thoroughly.
Excessive bearing wear can be detected through increased
vibration. If this symptom appears, contact an experienced and
responsible service organization to perform vibration analysis
on the compressor.
Compressor Rotor Check — Use Carrier specified
oil. Excessive compressor rotor wear is shown by a lack of
performance. If a lack of performance is noted, have the
compressor rotors inspected by a trained service person.
The rotors can be visually inspected once every 5 to
10 years or as needed depending on chiller operating
conditions.
Motor Insulation — Periodic checks of the motor insula-
tion are not necessary. A 500-v megohmmeter test is recom-
mended to assist troubleshooting if there are indications of
problems including, but not limited to, moisture in the refriger-
ant, and chronic current imbalance or over current trips. See
guidelines for megohmmeter test in the Before Initial Start-Up,
Ground Fault Troubleshooting section on page 58.
Inspect the Heat Exchanger Tubes
COOLER — Inspect and clean the cooler tubes at the end of
the first operating season. Because these tubes have internal
ridges, a rotary-type tube cleaning system is necessary to fully
clean the tubes. Upon inspection, the tube condition will deter-
mine the scheduled frequency for cleaning, and will indicate
whether liquid treatment is adequate in the chilled liquid/
brine circuit. Inspect the entering and leaving chilled liquid
temperature sensors for signs of corrosion or scale. Replace the
sensor if corroded or remove any scale if found.
CONDENSER — Since this liquid circuit is usually an open-
type system, the tubes may be subject to contamination and
scale. Clean the condenser tubes with a rotary tube cleaning
system at least once per year and more often if the liquid is
contaminated. Inspect the entering and leaving condenser liq-
uid sensors for signs of corrosion or scale. Replace the sensor if
corroded or remove any scale if found.
Higher than normal condenser pressures, together with the
inability to reach full refrigeration load, usually indicate dirty
tubes or air in the chiller. If the refrigeration log indicates a rise
above normal condenser pressures, check the condenser refrig-
erant temperature against the leaving condenser liquid temper-
ature. If this reading is more than what the design difference is
supposed to be, then the condenser tubes may be dirty or liquid
flow may be incorrect. Because HFC-134a is a high-pressure
refrigerant, air usually does not enter the chiller.
During the tube cleaning process, use brushes especially
designed to avoid scraping and scratching the tube wall.
Contact your Carrier representative to obtain these brushes. Do
not use wire brushes.
Water/Brine Leaks — Moisture in the refrigerant is in-
dicated during chiller operation by the refrigerant moisture
indicator on the refrigerant motor cooling line. See Fig. 2.
Leaks should be repaired immediately.
Water/Brine Treatment — Untreated or improperly
treated water/brine may result in corrosion, scaling, erosion, or
algae. The services of a qualified water/brine treatment special-
ist should be obtained to develop and monitor a treatment
program.
Inspect the Control Center — Before working on
any starter, shut off the chiller, open and tag all disconnects
supplying power to the control center.
CAUTION
The motor leads must be disconnected from the VFD
before an insulation test is performed. The voltage gener-
ated from the test equipment can damage the solid-state
VFD components.
CAUTION
Hard scale may require chemical treatment for its preven-
tion or removal. Consult a liquid treatment specialist for
proper treatment. Failure to properly treat liquid could
result in property damage or personal injury.
CAUTION
The chiller must be dehydrated after repair of liquid leaks.
See Chiller Dehydration section, page 55. Failure to dehy-
drate the chiller after repair of liquid leaks could result in
equipment damage or personal injury.
CAUTION
Water/brine must be within design flow limits, clean, and
treated to ensure proper chiller performance and to reduce
the potential of tubing damage due to corrosion, scaling,
erosion, and algae. Carrier assumes no responsibility for
chiller damage resulting from untreated or improperly
treated water/brine.
WARNING
Before working on any VFD, shut off the chiller, open and
tag all disconnects supplying power to the starter. After dis-
connecting input power to a VFD and before touching any
internal components, wait 5 minutes for the DC bus capaci-
tors to discharge, then check the voltage with a voltmeter.
Failure to observe this warning could result in severe
bodily injury or death.
WARNING
The disconnect on the front of the control center does not
deenergize all internal circuits. Open all internal control
power and remote disconnects before servicing the starter.