Goodmans SSX, GSZ, ASZ, ASX, DSZ, DSX, GSX Overfeeding, Underfeeding, Superheat, Checking Subcooling

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SERVICING

S-106 OVERFEEDING

Overfeeding by the expansion valve results in high suction pressure, cold suction line, and possible liquid slugging of the compressor.

If these symptoms are observed:

1.Check for an overcharged unit by referring to the cooling performance charts in the servicing section.

2.Check the operation of the power element in the valve as explained in S-110 Checking Expansion Valve Operation.

3.Check for restricted or plugged equalizer tube.

S-107 UNDERFEEDING

Underfeeding by the expansion valve results in low system capacity and low suction pressures.

If these symptoms are observed:

1.Check for a restricted liquid line or drier. A restriction will be indicated by a temperature drop across the drier.

2.Check the operation of the power element of the valve as described in S-110 Checking Expansion Valve Operation.

S-108 SUPERHEAT

The expansion valves are factory adjusted to maintain 8 to 12 degrees superheat of the suction gas. Before checking the superheat or replacing the valve, perform all the procedures outlined under Air Flow, Refrigerant Charge, Expansion Valve

-Overfeeding, Underfeeding. These are the most common causes for evaporator malfunction.

CHECKINGSUPERHEAT

Refrigerant gas is considered superheated when its tempera- ture is higher than the saturation temperature corresponding to its pressure. The degree of superheat equals the degrees of temperature increase above the saturation temperature at existing pressure. See Temperature - Pressure Chart on following pages.

CAUTION

To prevent personal injury, carefully connect and disconnect manifold gauge hoses. Escaping liquid refrigerant can cause burns. Do not vent refrigerant to atmosphere. Recover during system repair

or final unit disposal.

1.Run system at least 10 minutes to allow pressure to stabilize.

2.Temporarily install thermometer on suction (large) line near suction line service valve with adequate contact and insulate for best possible reading.

3.Refer to the superheat table provided for proper system superheat. Add charge to lower superheat or recover charge to raise superheat.

Superheat Formula = Suct. Line Temp. - Sat. Suct. Temp.

EXAMPLE:

a.Suction Pressure = 143

b.Corresponding Temp. °F. = 50

c.Thermometer on Suction Line = 61°F.

To obtain the degrees temperature of superheat, subtract 50.0 from 61.0°F.

The difference is 11° Superheat. The 11° Superheat would fall in the ± range of allowable superheat.

SUPERHEAT AND SUBCOOLING ADJUSTMENT ON TXV APPLICATIONS

1.Run system at least 10 minutes to allow pressure to stabilize.

2.Temporarily install thermometer on liquid (small) line near liquid line service valve with adequate contact and insulate for best possible reading.

3.Check subcooling and superheat. Systems with TXV application should have a subcooling and superheat of 7 ± 2ºF.

a.If subcooling and superheat are low, adjust TXV to 7 - 9ºF then check subcooling.

b.If subcooling is low and superheat is high, add charge to raise subcooling to 7 ± 2ºF then check superheat.

c.If subcooling and superheat are high, adjust TXV valve to 7 ± 9ºF then check subcooling.

d.If subcooling is high and superheat is low, adjust TXV valve to 7 to 9ºF superheat and remove charge to lower the subcooling to 7 ± 2ºF.

The TXV should NOT be adjusted at light load conditions 55º to 60ºF, under such conditions only the subcooling can be evaluated. This is because suction pressure is dependent on the indoor coil match, indoor airflow, and wet bulb temperature. NOTE: Do NOT adjust charge based on suction pressure unless there is a gross undercharge.

4. Disconnect manifold set. Installation is complete.

S-109 CHECKING SUBCOOLING

Refrigerant liquid is considered subcooled when its tempera- ture is lower than the saturation temperature corresponding to its pressure. The degree of subcooling equals the degrees of temperature decrease below the saturation temperature at the existing pressure.

1.Attach an accurate thermometer or preferably a thermo- couple type temperature tester to the liquid line as it leaves the condensing unit.

2.Install a high side pressure gauge on the high side (liquid) service valve at the front of the unit.

3.Record the gauge pressure and the temperature of the line.

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Contents Service Instructions Important Information Recognize Safety SYMBOLS, Words and LabelsEmail us at customerservice@goodmanmfg.com Fax us at 713 Fax us at 931 438Safe Refrigerant Handling Product Identification Split System Heat Pumps R410AModel # Description Split System Air Conditioners R410A ASX130**1AA Single Piece Air Handlers AWUF****1AA MBR/MBE Air Handlers Product Identification 1824 3642 Accessories ASX13DSX/SSX16 ASX18 ASZ13 DSZ/SSZ16 ASZ18 Expansion Valve Kits FSK01A Coil Accessories Electric Heat Kitapplications Aruf Electric Heat Kitapplications Aepf Product Design Condensing UnitFigure a Capacity Control Cooling System OperationHeating Cooling CycleDefrost Cycle Heating CycleCooling Cycle System Operation AFE18-60A Control Board DescriptionTroubleshooting Chart COOLING/HP Analysis ChartServicing 61B3A Thermostat and Wiring Checking WiringChecking THERMOSTAT, WIRING, and Anticipator Checking Voltage3B Cooling Anticipator 3C Heating AnticipatorChecking Transformer Control Circuit Checking Time Delay RelayTesting Coil Circuit Checking Cycle ProtectorChecking Contactor AND/OR Relays Testing Compressor ContactorSingle Phase Checking Contactor ContactsCopeland Comfort Alert Diagnostics Testing FAN RelayDiagnostics Table Checking LOW Pressure Control Checking Loss of Charge ProtectorChecking High Pressure Control Checking Capacitor15A Resistance Check 15B Capacitance CheckRELAY, Start 16A Checking FAN and Blower Motor Windings PSC Motors 16B Checking FAN and Blower Motor ECM MotorsChart on Next Chart from Previous 16D ECM CFM Adjustments MBE / Aepf 16C Checking ECM Motor WindingsCFM 16E Blower Performance Data 16F Checking GE X13TM MotorsGE X13TM Motor Connections 17A Resistance Test Testing Compressor WindingsChecking Compressor 17B Ground Test17D Operation Test 17C Unloader Test ProcedureUnloader Test Procedure Compressor Ground TestTesting Defrost Thermostat Testing Crankcase Heater Optional ItemTesting Defrost Control Checking Reversing Valve and SolenoidChecking Heater Elements 40 MBR/AR*F Electronic Blower Time Delay RelayChecking Heater Limit Controls Sequence of OperationMBR/AR*F with Single Stage Heat Pumps Heating Operation41 MBE/AEPF with GSX, SSX, ASX, DSX Defrost OperationMBE/AEPF with Single Stage GSX, ASX and SSX Condensers 41A MBE/AEPF with Single Stage GSZ, SSZ, & ASZ Heat Pumps Sequence of Operation MBE/AEPF with TWO Stage ASX & DSX CondensersMBE/AEPF with TWO Stage ASZ & DSZ Heat Pump Units Electric Heater Optional Item 61A Checking Heater Limit Controls 61B Checking Heater Fuse Link Optional Electric HeatersFormulas Evacuation Leak Testing Nitrogen or NITROGEN-TRACEDRefrigeration Repair Practice Brazing MaterialsCharging EvacuationFinal Charge Adjustment Checking Compressor Efficiency105B Thermostatic Expansion Valve TXV ValvesPressure vs. Temperature Chart 410A Required Liquid Line Temperature Superheat OverfeedingUnderfeeding Checking SubcoolingFixed Orifice Restrictor Devices 109A TWO Speed ApplicationChecking Expansion Valve Operation Subcooling Formula = Sat. Liquid Temp. Liquid LineNON-CONDENSABLES Checking Restricted Liquid LineOvercharge of Refrigerant Compressor BurnoutLong Line SET Application R-410A Accessories for lines greater than 80 feetRefrigerant Piping Tube SizingInstallation Requirements AIR Handler External Static Initial System ChargingCoil Static Pressure Drop Total External StaticStatic Pressure Drop Accessories Wiring Diagrams ALL Fuel System AFE18-60A Control Board10kw and Below, One Stage Electric Heat OT/EHR18-60 #2 GRD PLM PLF XFMR-R XFMR-C After Installing Optional Heat KIT, Mark AN X Provided Above HKR Heat Kit GRD PLM PLF
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