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.
Failure to do so could result in serious injury or 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 result in serious injury or death.
Undercharged Refrigerant Systems |
| A check of the amperage drawn by the compressor | |
An undercharged system will result in poor performance | motor should show a lower reading. (Check the Unit | ||
(low pressures, etc.) in both the heating and cooling cycle. | Specification.) After the unit has run 10 to 15 minutes, | ||
Whenever you service a unit with an undercharge | of | check the gauge pressures. Gauges connected to system | |
with an undercharge will have low head pressures and | |||
refrigerant, always suspect a leak. The leak must | be | ||
substantially low suction pressures. | |||
repaired before charging the unit. |
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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 and thawing can also be caused by insufficient air over 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 | of the evaporator will not be encountered because the | ||
Compressor amps will be near normal or higher. | refrigerant will boil later if at all. Gauges connected to | ||
system will usually have higher head pressure (depending | |||
Noncondensables can also cause these symptoms. | upon amount of over charge). Suction pressure should be | ||
To confirm, remove some of the charge, if conditions | slightly higher. | ||
improve, system may be overcharged. If conditions don’t |
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improve, Noncondensables are indicated. |
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Whenever an overcharged system is indicated, always |
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make sure that the problem is not caused by air flow |
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problems. Improper air flow over the evaporator coil may |
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indicate some of the same symptoms as an over charged |
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system. |
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An overcharge can cause the compressor to fail, since it |
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would be “slugged” with liquid refrigerant. |
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The charge for any system is critical. When the compressor |
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is noisy, suspect an overcharge, when you are sure that |
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the air quantity over the evaporator coil is correct. Icing |
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