Carrier 38AU appendix Compressor Protection

Page 37

 

Table 12 – CADM Troubleshooting

 

 

Miswired Module Indication

Recommended Troubleshooting Action

Green LED is not on,

Determine if both R and C module terminals are connected. Verify voltage in present at module’s R

module does not power up

and C terminals.

 

NOTE: The CADM requires a constant nominal 24VAC power supply. The wiring to the module’s R

 

and C terminals must be directly from the control transformer. The module cannot receive its power

 

from another device that will interrupt the 24VAC power supply. See the 38AU Wiring Diagram(s)

 

(Fig. 29 and Fig. 30).

 

 

Green LED Intermittent,

Determine if R and Y terminals are wired in reverse. Verify module’s R and C terminals have a con-

module powers up only

stant source. See “NOTE” above for details on R and C wiring.

when compressor runs

 

 

 

TRIP LED is on but system

Verify Y terminal is wired properly per the 38AU wiring diagram (see Fig. 29 and Fig. 30). Verify

and compressor check OK

voltage at contactor coil falls below 0.5VAC when off. Verify 24VAQC is present across Y and C

 

when thermostat demand signal is present. If not, R and C are reverse wired.

 

 

TRIP LED and ALERT LED

Verify R and C terminals are supplied with 19-28VAC.

flashing together

 

 

 

ALERT Flash Code 3

Verify Y terminal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below

(Compressor Short Cycling)

0.5VAC when off.

displayed incorrectly

 

 

 

ALERT Flash Code 5 or 6

Check that compressor T1 and T3 wires are through module’s current sensing holes. Verify Y ter-

(Open Circuit, Missing Phase)

minal is connected to 24VAC at contactor coil. Verify voltage at contactor coil falls below 0.5VAC

displayed incorrectly

when off.

 

 

Alert Flash Code *

Determine if module’s Y terminal is connected. Verify Y terminal is connected to 24VAC at contactor

(Welded Contactor)

coil. Verify 24VAC is present across Y and C when thermostat demand signal is present. If not, R

displayed incorrectly

and C are reverse wired. Verify voltage at contactor coil falls below 0.5VAC when off.

 

 

38AU

Compressor Protection

Compressor Overtemperature Protection (IP) —

A thermostat installed on the compressor motor winding reacts to excessively high winding temperatures and shuts off the compressor.

Crankcase Heater —

The heater minimizes absorption of liquid refrigerant by oil in the crankcase during brief or extended shutdown periods. The heater is wired to cycle with the compressor; the heater is off when compressor is running, and on when compressor is off.

The crankcase heater will operate as long as the power circuit is energized. The main disconnect must be on to energize the crankcase heater.

IMPORTANT: Never open any switch or disconnect that energizes the crankcase heater unless unit is being serviced or is to be shut down for a prolonged period. After a prolonged shutdown on a service job, energize the crankcase heater for 24 hours before starting the compressor.

Advanced Scroll Temperature Protection (ASTP) —

See “Advanced Scroll Temperature Protection (ASTP)” on page 24.

Low-Pressure Switch —

The 38AU low-pressure switch is stem-mounted on the suction line. Switches are all fixed, non-adjustable type.

High-Pressure Switch —

The high-pressure switch is stem mounted on the discharge line. The switch is a fixed, non-adjustable type.

Outdoor Fans —

Each fan is supported by a formed-wire mount bolted to the fan deck and covered with a wire guard. Fan motors have permanently lubricated bearings.

1.Shut off unit power supply. Install lockout tag.

2.Remove outdoor fan assembly (grille, motor, and fan).

3.Loosen fan hub setscrews.

4.Adjust fan height as shown in Fig. 33.

5.Tighten setscrews to 84 in-lbs (949 N-cm).

6.Replace outdoor fan assembly.

3.6 mm +0/0/-0.8

C10103

Fig. 33 - Outdoor Fan Blade Position

Lubrication —

Fan Motors: The fan motors have sealed bearings. No provisions are made for lubrication.

Compressor: The compressor has its own oil supply. Loss of oil due to a leak in the system should be the only reason for adding oil after the system has been in operation.

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Contents Contents Installation, Start---Up Service InstructionsInstallation Guideline Safety ConsiderationsReplacement/Retrofit R-22 to PuronR Unit Damage Hazard InstallationMchx UnitRtpf 38AUD*25 38AUZ*25Refrigerant TYPE‡ Unit Size 38AUCompressor Condenser FansNominal Capacity kW Pressurestat Settings kPa High CutoutRtpf Shipping Charge kg ScrollOil Charge A/B oz Rtpf Shipping Charge A/B lbFace Area sq ft total Rows/Fins per inch FPI Rtpf Shipping Charge A/B kg Operating Weight kg Novation Coil Al TubeOil Charge A/B L Qty...r/s Motor Hp Nema Diameter mmU Z a 2 5 a 0 G 6 a 0 a 0 a Matching 38AU Model To Evaporator Coil InstallationJobsite Survey Do not Bury Refrigeration LinesSlab Mount Provide Safety ReliefEquivalent Lengths for Common Fittings ft Check 38AU Model with Evaporator Coil ConnectionsSuction Riser Liquid Lift38AUZ 16-25 Piping Recommendations Single-Circuit Unit Vertical Separation outdoor unit above indoor unit 38AUD 16-25 Piping Recommendations Two-Circuit UnitInsulate Suction Lines Hot Gas BypassRefrigerant Specialties Part Numbers Install Filter Driers and Moisture IndicatorsCapacity Control Liquid Line Solenoid Valve Install Liquid Line Solenoid ValveSelecting an Accumulator Make Piping ConnectionsPreliminary Charge Evacuation/DehydrationUnits with Factory-Installed Disconnect Field Power SupplyFire Hazard All UnitsElectrical Operation Hazard Convenience OutletsConvenience Outlet Utilization Notice Label Field Control WiringThermostat Control Transformer WiringUnbalanced 3-Phase Supply Voltage Unit Wire/Fuse or Hacr Breaker Sizing DataSTART-UP PRE-START-UPSystem Check Preliminary ChecksAdjust Refrigerant Charge Advanced Scroll Temperature Protection AstpUsing plotted operating point Start UnitFinal Checks 38AUZ*25 Check Compressor Oil Level38AUD*16 Charging Chart Novation 38AUZ*16 Charging Chart Rtpf 38AUD*16 Charging Chart Rtpf 38AUD*25 Charging Chart Rtpf Typical 38AUZ Wiring Diagram 15 Ton 230V Tandem Unit Shown Typical 38AUD Wiring Diagram 15 Ton 230V Dual Unit Shown Base Unit Controls Operating SequenceService Routine System MaintenanceRefrigeration System Equipment Damage HazardFactory High-Flow Access Ports Field Refrigerant Access PortsLiquid Line Filter Drier Input Terminal Voltage Comfort Alert Diagnostic ModuleLockout LED Status CodesCompressor Protection 38AUD Size 16 Cabinet LPS 38AUZ,D Size 25 Cabinet 38AUZ*25 Compressor Assembly Rear View Repairing Novation Condenser Tube Leaks Novation Coil Cleaning and MaintenanceCoil Type Identification NOVATIONt TypeReplacing NOVATIONt Condenser Coil Routine Cleaning of Round-Tube Plate Fin Rtpf CoilsUnit Reliability Hazard Problem Solution Compressor does not RUN TroubleshootingCompressor Stops on HIGH-PRESSURE Switch Fastener Torque ValuesCompressor Running but Cooling Insufficient Problem Solution Compressor Cycles on LOW-PRESSURE SwitchUnit Operates TOO Long or Continuously System is NoisyAppendix a Wiring Diagram ListAppendix B Troubleshooting Low Ambient Option Factory InstalledAppendix C Operation38AUZ*16 & 38AUD*16 Novation 38AUZ*16/25 & 38AUD*16/25 Rtpf Motormaster Sensor LocationDimensions --- Inches Unit Baffle Wind Baffle DimensionDimensions --- MM Unit Baffle Wind Baffles Fabrication 15 Ton Wind Baffle Brackets Fabrication Front Front Back Left Right Catalog No 38AU---09SI II. PRE-START-UP Outdoor Unit START-UP ChecklistCheck Voltage Imbalance