SERVICING
2.Remove the orifice or tube strainer assembly and re- place.
3.Replace liquid line drier, evacuate and recharge.
CHECKING EQUALIZATION TIME
During the "OFF" cycle, the high side pressure bleeds to the low side through the fixed orifice restriction device. Check equalization time as follows:
1.Attach a gauge manifold to the suction and liquid line dill valves.
2.Start the system and allow the pressures to stabilize.
3.Stop the system and check the time it takes for the high and low pressure gauge readings to equalize.
If it takes more than seven (7) minutes to equalize, the restrictor device is inoperative. Replace, install a liquid line drier, evacuate and recharge.
S-112 CHECKING RESTRICTED LIQUID LINE
When the system is operating, the liquid line is warm to the touch. If the liquid line is restricted, a definite temperature drop will be noticed at the point of restriction. In severe cases, frost will form at the restriction and extend down the line in the direction of the flow.
Discharge and suction pressures will be low, giving the appearance of an undercharged unit. However, the unit will have normal to high subcooling.
Locate the restriction, replace the restricted part, replace drier, evacuate and recharge.
S-113 OVERCHARGE OF REFRIGERANT
An overcharge of refrigerant is normally indicated by an excessively high head pressure.
An evaporator coil, using an expansion valve metering device, will basically modulate and control a flooded evaporator and prevent liquid return to the compressor.
An evaporator coil, using a capillary tube metering device, could allow refrigerant to return to the compressor under extreme overcharge conditions. Also with a capillary tube metering device, extreme cases of insufficient indoor air can cause icing of the indoor coil and liquid return to the compressor, but the head pressure would be lower.
There are other causes for high head pressure which may be found in the "Service Problem Analysis Guide."
If other causes check out normal, an overcharge or a system containing
If this system is observed:
1.Start the system.
2.Remove and capture small quantities of gas from the suction line dill valve until the head pressure is reduced to normal.
3.Observe the system while running a cooling performance test. If a shortage of refrigerant is indicated, then the system contains
S-114 NON-CONDENSABLES
If
S-115 COMPRESSOR BURNOUT
When a compressor burns out, high temperature develops causing the refrigerant, oil and motor insulation to decom- pose forming acids and sludge.
If a compressor is suspected of being
NOTICE
Violation of EPA regulations may result in fines or other penalties.
Now determine if a burn out has actually occurred. Confirm by analyzing an oil sample using a Sporlan Acid Test Kit, AK- 3 or its equivalent.
Remove the compressor and obtain an oil sample from the suction stub. If the oil is not acidic, either a burnout has not occurred or the burnout is so mild that a complete
If acid level is unacceptable, the system must be cleaned by using the
CAUTION
Do not allow the sludge or oil to contact the skin. Severe burns may result.
NOTE: The Flushing Method using
Suction Line Drier Clean-Up Method
The POE oils used with R410A refrigerant is an excellent solvent. In the case of a burnout, the POE oils will remove any burnout residue left in the system. If not captured by the refrigerant filter, they will collect in the compressor or other system components, causing a failure of the replacement compressor and/or spread contaminants throughout the system, damaging additional components.
Use AMANA® brand part number RF000127 suction line filter drier kit. This drier should be installed as close to the compressor suction fitting as possible. The filter must be accessible and be rechecked for a pressure drop after the system has operated for a time. It may be necessary to use new tubing and form as required.
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