Inspect Relief Valves And Piping; Compressor Bearing And Gear Maintenance; Inspect The Heat Exchanger Tubes And Flow Devices - Carrier AquaEdge 19XR Start-Up, Operation And Maintenance Instructions Manual

LEGEND
1 — Float Ball
2 — Refrigerant Exit
3 — Bearings
Fig. 32 — Economizer Float System (Two-Stage Compressor Chiller)

Inspect Relief Valves and Piping

The relief valves on this chiller protect the system against the po-
tentially dangerous 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,
inspect the relief valves at more frequent intervals.

Compressor Bearing and Gear Maintenance

The key to good bearing and gear maintenance is proper lubri-
cation. Use the proper grade of oil, maintained at recommend-
ed level, temperature, and pressure. Inspect the lubrication sys-
tem regularly and thoroughly. Annual oil analysis and vibration
measurements are recommended.
Excessive bearing wear can sometimes be detected through in-
creased vibration or increased bearing temperature. Gears, bab-
bitted journal bearings, and thrust bearings should be examined
for signs of wear based on the results of the annual oil analysis
and vibration levels. To inspect the bearings, a complete com-
pressor teardown is required. Only a trained service technician
should remove and examine the bearings. The frequency of ex-
amination is determined by the hours of chiller operation, load
conditions during operation, and the condition of the oil and the
lubrication system. High speed shaft rolling element bearings
cannot be field inspected; excessive vibration is the primary sign
of wear or damage. If either symptom appears, contact an expe-
rienced and responsible service organization for assistance.
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Inspect the Heat Exchanger Tubes and
Flow Devices
COOLER AND OPTIONAL FLOW DEVICES
Inspect and clean the cooler tubes at the end of the first operat-
ing season. Because these tubes have internal ridges, a rotary-
type tube cleaning system is needed to fully clean the tubes. In-
spect the tubes' condition to determine the scheduled frequen-
cy for future cleaning and to determine whether water treat-
ment in the chilled water/brine circuit is adequate. Inspect the
entering and leaving chilled water temperature sensors and
flow devices for signs of corrosion or scale. Replace a sensor
or Schrader fitting if corroded or remove any scale if found.
CONDENSER AND OPTIONAL FLOW DEVICES
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 cleaning system at least
once per year and more often if the water is contaminated. In-
spect the entering and leaving condenser water sensors and
flow devices for signs of corrosion or scale. Replace the sensor
or Schrader fitting if corroded or remove any scale if found.
Higher than normal condenser pressures, together with the in-
ability 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 water tempera-
ture. If this reading is more than what the design difference is
supposed to be, the condenser tubes may be dirty or water flow
may be incorrect. Because HFC-134a is a high-pressure refrig-
erant, air usually does not enter the chiller.
During the tube cleaning process, use brushes specially de-
signed to avoid scraping and scratching the tube wall. Contact
your Carrier representative to obtain these brushes. Do not use
wire brushes.
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