WARNING
ELECTRIC SHOCK HAZARD
Turn off electric power before service or installation.
Extreme care must be used, if it becomes necessary to work on equipment with power applied.
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death.
WARNING
HIGH PRESSURE HAZARD
Sealed Refrigeration System contains refrigerant and oil under high pressure.
Proper safety procedures must be followed, and proper protective clothing must be worn when working with refrigerants.
Failure to follow these procedures could UHVXOWLQVHULRXVLQMXU\RUGHDWK
Undercharged Refrigerant Systems
An undercharged system will result in poor performance (low pressures, etc.) in both the heating and cooling cycle.
Whenever you service a unit with an undercharge of refrigerant, always suspect a leak. The leak must be repaired before charging the unit.
To check for an undercharged system, turn the unit on, allow the compressor to run long enough to establish working pressures in the system (15 to 20 minutes).
During the cooling cycle you can listen carefully at the exit of the metering device into the evaporator; an intermittent hissing and gurgling sound indicates a low refrigerant charge. Intermittent frosting and thawing of the evaporator is another indication of a low charge, however, frosting DQG WKDZLQJ FDQ DOVR EH FDXVHG E\ LQVXI¿FLHQW DLU RYHU the evaporator.
Checks for an undercharged system can be made at the compressor. If the compressor seems quieter than normal, it is an indication of a low refrigerant charge.
Overcharged Refrigerant Systems
Compressor amps will be near normal or higher. Noncondensables can also cause these symptoms. 7R FRQ¿UP UHPRYH VRPH RI WKH FKDUJH LI FRQGLWLRQV improve, system may be overcharged. If conditions don’t improve, Noncondensables are indicated.
Whenever an overcharged system is indicated, always PDNH VXUH WKDW WKH SUREOHP LV QRW FDXVHG E\ DLU ÀRZ SUREOHPV,PSURSHUDLUÀRZRYHUWKHHYDSRUDWRUFRLOPD\ indicate some of the same symptoms as an over charged system.
An overcharge can cause the compressor to fail, since it would be “slugged” with liquid refrigerant.
The charge for any system is critical. When the compressor is noisy, suspect an overcharge, when you are sure that the air quantity over the evaporator coil is correct. Icing
A check of the amperage drawn by the compressor motor should show a lower reading. (Check the Unit 6SHFL¿FDWLRQ $IWHU WKH XQLW KDV UXQ WR PLQXWHV check the gauge pressures. Gauges connected to system with an undercharge will have low head pressures and substantially low suction pressures.
of the evaporator will not be encountered because the refrigerant will boil later if at all. Gauges connected to system will usually have higher head pressure (depending upon amount of over charge). Suction pressure should be slightly higher.
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