Emerson Liebert InteleCool 2, Руководство пользователя

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Maintenance
16
6.5.1 Refrigerant Lines
Check all refrigerant lines and capillaries for vibration isolation, and support as necessary. Visually
inspect all refrigerant lines for leaks.
6.5.2 Discharge Pressure
Discharge pressure can be increased or decreased by load conditions or condenser efficiency. The
high-pressure switch will shut the compressor/contactor at its cut-out setting of 400 PSIG (2758 kPa).
See 5.4.2 - High Pressure (Standard) .
6.5.3 Thermostatic Expansion Valve
The thermostatic expansion valve (TEV) keeps the evaporator supplied with enough refrigerant to
satisfy load conditions. It does not turn the compressor on or off, but maintains proper refrigerant
super heat in the suction gas to the compressor.
Determine TEV operation by measuring superheat. If too little refrigerant is being fed to the
evaporator, the superheat will be high; if too much refrigerant is being supplied, the superheat will be
low. The correct superheat setting is between 10° and 20°F (5.5° and 11.1°C), under normal load
conditions and “steady-state” operation. Some models of Liebert InteleCool2 will be supplied with a
non-adjustable expansion valve, so no adjustments are possible.
To adjust the superheat setting when an adjustable valve is used:
1. Remove the valve cap from the base of the valve.
2. Turn the adjustment stem counter-clockwise to lower the superheat.
3. Turn the adjustment stem clockwise to increase the superheat.
To determine superheat:
1. Measure the temperature of the suction line at the point where the TEV bulb is clamped.
2. Obtain the gauge pressure at the compressor suction valve.
3. Add the estimated pressure drop between bulb location and the suction valve.
4. Convert the sum of the two pressures to the saturated temperature.
5. Subtract this temperature from the actual suction line temperature. The difference is superheat.
6.5.4 Air-Cooled Condenser
Restricted airflow through the condenser coil will reduce the operating efficiency of the unit and can
result in high compressor head pressure and loss of cooling.
Clean the condenser coil each time the evaporator filters are replaced. Check for bent or damaged coil
fins and repair as needed. Check all refrigerant lines for leaks. Clean the condenser coil of all debris
that will inhibit airflow. This can be done with compressed air or commercial coil cleaner.
6.6 Compressor
Infrequently, a fault in the motor insulation may result in a motor burn. However, in a properly
installed system, burnouts rarely occur. Of those that do, most are the result of mechanical or
lubrication failures, resulting in the burnout as a secondary consequence.
If the problems that can cause compressor failures are detected and corrected early, a large
percentage can be prevented. Periodic maintenance inspections by alert service personnel on the
lookout for abnormal operation can be a major factor in reducing maintenance costs. It is easier and
far less costly to take the steps necessary to ensure proper system operation than it is to allow a
compressor to fail and require replacement.
When troubleshooting a compressor, check all electrical components for proper operation, including
all fuses and circuit breakers and pressure switch operation.
If a compressor failure has occurred, determine whether it is an electrical or mechanical failure.
NOTE
Make no more than 1/4 turn of the stem at a time. As long as 30 minutes may be required for
the new balance to take place.