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Inspect Refrigerant Float System — Perform
inspection every 5 years or when the condenser is opened
for service. Transfer the refrigerant into the cooler vessel or
into a storage tank. Remove the float access cover. Clean the
chamber and valve assembly thoroughly. Be sure that the
valve moves freely. Make sure that all openings are free of
obstructions. Examine the cover gasket and replace if nec-
essary. See Fig. 37 for views of both float valve designs. On
the linear float valve design, inspect orientation of the float
slide pin. It must be pointed toward the bubbler tube for proper
operation.
Inspect Relief Valves and Piping — The relief valves
on this chiller protect the system against the potentially dan-
gerous 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 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 and Gear Mainten-
ance —
The key to good bearing and gear maintenance is
proper lubrication. Use the proper grade of oil, maintained
at recommended level, temperature, and pressure. Inspect the
lubrication system regularly and thoroughly.
To inspect the bearings, a complete compressor teardown
is required. Only a trained service technician should remove
and examine the bearings. The cover plate on older com-
pressor bases was used for factory-test purposes, and is not
usable for bearing or gear inspection. The bearings and gears
should be examined on a scheduled basis for signs of wear.
The frequency of examination is determined by the hours of
chiller operation, load conditions during operation, and the
condition of the oil and the lubrication system. Excessive
bearing wear can sometimes be detected through increased
vibration or increased bearing temperature. If either symp-
tom appears, contact an experienced and responsible service
organization for assistance.
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
determine the scheduled frequency for cleaning, and will
indicate whether water treatment is adequate in the chilled
water/brine circuit. Inspect the entering and leaving chilled
water temperature sensors for signs of corrosion or scale.
Replace the sensor if corroded or remove any scale if found.
CONDENSER — Since this water circuit is usually an open-
type system, the tubes may be subject to contamination and
scale. Clean the condenser tubes with a rotary tube clean-
ing system at least once per year, and more often if the water
is contaminated. Inspect the entering and leaving condenser
water 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
refrigerant temperature against the leaving condenser water
temperature. If this reading is more than what the design
difference is supposed to be, then the condenser tubes may
be dirty, or water flow may be incorrect. Because HCFC-22
and HFC134-a are high-pressure refrigerants, air usually does
not enter the chiller, rather, the refrigerant leaks out.
During the tube cleaning process, use brushes especially
designed to avoid scraping and scratching the tube wall. Con-
tact your Carrier representative to obtain these brushes. Do
not use wire brushes.
Hard scale may require chemical treatment for its pre-
vention or removal. Consult a water treatment specialist
for proper treatment.
Water Leaks — Water is indicated during chiller opera-
tion by the refrigerant moisture indicator (Fig. 2A or 2B) on
the refrigerant motor cooling line. Water leaks should be re-
paired immediately.
Chiller must be dehydrated after repair of water leaks.
See Chiller Dehydration section, page 47.
Fig. 37 — 19XL Float Valve Designs
64