Goodman Mfg R-410A manual Checking Expansion Valve Operation, Checking Restricted Liquid Line

SERVICING

S-110 CHECKING EXPANSION VALVE OPERATION

1.Remove the remote bulb of the expansion valve from the suction line.

2.Start the system and cool the bulb in a container of ice water, closing the valve. As you cool the bulb, the suction pressure should fall and the suction temperature will rise.

3.Next warm the bulb in your hand. As you warm the bulb, the suction pressure should rise and the suction tempera- ture will fall.

4.If a temperature or pressure change is noticed, the expan- sion valve is operating. If no change is noticed, the valve is restricted, the power element is faulty, or the equalizer tube is plugged.

5.Capture the charge, replace the valve and 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 ap- pearance of an undercharged unit. However, the unit will have normal to high subcooling.

If a restriction is located, replace the restricted part, replace drier, evacuate and recharge.

S-113 REFRIGERANT OVERCHARGE

An overcharge of refrigerant is normally indicated by exces- sively high head pressure and/or liquid return to the compres- sor.

If high head pressure is not indicated, an overcharge or a sys- tem containing non-condensables could be the problem.

If overcharging is indicated:

1.Start the system.

2.Remove 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 sys- tem contains non-condensables. See S-114 Non- Condensables.

S-114 NON-CONDENSABLES

Check for non-condensables.

1.Shut down the system and allow the pressures to equalize for a minimum of 15 minutes.

2.Take a pressure reading.

3.Compare this pressure to the temperature of the coldest coil since this is where most of the refrigerant will be. If the pressure indicates a higher temperature than that of the coil temperature, non-condensables are present.

To remove the non-condensables.

1.Remove the refrigerant charge.

2.Replace and/or install liquid line drier

3.Evacuate and recharge.

S-115 COMPRESSOR BURNOUT

When a compressor burns out, high temperature develops caus- ing the refrigerant, oil and motor insulation to decompose form- ing acids and sludge.

If a compressor is suspected of being burned-out, attach a refrigerant hose to the liquid line dill valve and properly remove and dispose of the refrigerant.

VIOLATION OF EPA REGULATIONS MAY RESULT IN FINES OR OTHER PENALITIES.

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 clean-up is not necessary.

If acid level is unacceptable, the system must be cleaned by using the clean-up drier method.

DO NOT ALLOW THE SLUDGE OR OIL TO CONTACT THE SKIN, SEVERE BURNS MAY RESULT.

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