Lennox International Inc 4HP18LT manual Fan Switch, System Switch, Indicating Light

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Fan Switch

In AUTO or INT (intermittent) mode, the blower operates only when the thermostat calls for heating or cooling. This mode is generally preferred when humidity control is a priority. The ON or CONT mode provides continuous indoor blower operation, regardless of whether the compressor or auxiliary heat are operating. This mode is required when constant air circulation or filtering is desired.

System Switch

Set the system switch for heating, cooling, or auto operation. The auto mode allows the heat pump to automatically switch from heating mode to cooling mode to maintain predetermined comfort settings. Many heat pump thermostats are also equipped with an emergency heat mode which locks out heat pump operation and provides temporary heat supplied by the auxiliary heat.

Indicating Light

Most heat pump thermostats have an amber light which indicates when the heat pump is operating in the emergency heat mode.

Temperature Indicator

The temperture indicator displays the actual room temperature.

Programmable Thermostats

Your system may be controlled by a programmable thermostat. These thermostats provide the added feature of programmable time-of-day set points for both heating and cooling. Refer to the user’s information manual provided with your particular thermostat for operation details.

Preservice Check

If your system fails to operate, check the following before calling for service:

Check to see that all electrical disconnect switches ar ON.

Make sure the thermostat temperature selector is properly set.

Make sure the thermostat system switch is properly set. Replace any blown fuses, or reset circuit breakers. Make sure unit access panels are in place.

Make sure air filter is clean.

Locate unit model number and have it handy before calling.

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 START-UP Refrigerant Charge AdjustmentRefrigerant Charging Issue R410A Temperature/Pressure Chart Approach Values for TXV Systems Issue Operation Compressor Delay Defrost Control Timing PinsTime Delay Pressure Switch CircuitInterpreting the Diagnostic LEDs System Diagnostic ModuleLED Description 24VAC Power Wiring Miswired Module Codes Thermostat Demand WiringMaintenance Temperature Setting Levers Inspect and clean outdoor coilHomeowner Information System Switch Fan SwitchTemperature Indicator Indicating LightStart-Up and Performance Checklist Wire Diagram Issue