Lennox International Inc 4HP18LT manual 24VAC Power Wiring

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Every time the module powers up, the last ALERT LED flash code that occurred prior to shutdown is displayed for

60 seconds. The module will continue to display the previous flash code until the condition returns to normal or 21VAC is removed from the module. TRIP and ALERT LEDs flashing at the same time means control circuit voltage is too low for operation.

24VAC Power Wiring

The diagnostic module requires a constant nominal 24VAC power supply. The wiring to the module’s R and C terminals must be directly from the indoor unit or thermostat. The module cannot be powered by R and C terminals on the defrost board without experiencing nuisance alerts.

Flash Codes (cont.)

Table 11

506470-01

Issue 1007

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Contents Lennox International Inc. Company Save these instructions for future referenceInstallation Clearances InstallationGeneral Torque TableSlab Mounting Electrical WiringSlab Mounting Roof MountingRefrigerant Piping Installing Refrigerant LineOutside Unit Placement & Installation PlacementLine Set Isolation Refrigerant Line Set DiametersRefrigerant Line Sets Installing Horizontal Runs Refrigerant Line Sets Transition from Vertical to Horizontal Required Euipment Flushing ProcedureExpansion Valve Systems Refrigerant Metering DeviceTo Close Liquid or Suction Line Service Valve To Access the Schrader PortEvacuation Using an Electronic Leak DetectorIssue Refrigerant Charge Adjustment START-UPRefrigerant Charging Issue R410A Temperature/Pressure Chart Approach Values for TXV Systems Issue Operation Compressor Delay Defrost Control Timing PinsTime Delay Pressure Switch CircuitSystem Diagnostic Module Interpreting the Diagnostic LEDsLED Description 24VAC Power Wiring Miswired Module Codes Thermostat Demand WiringMaintenance Inspect and clean outdoor coil Temperature Setting LeversHomeowner Information System Switch Fan SwitchTemperature Indicator Indicating LightStart-Up and Performance Checklist Wire Diagram Issue