Lennox International Inc 4HP18LT manual Slab Mounting, Roof Mounting, Electrical Wiring

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Install the unit high enough above the ground or roof to allow adequate drainage of defrost water and prevent ice buildup.

In heavy snow areas, do not locate the unit where drifting snow will occur. The unit base should be elevated above the depth of average snows.

NOTE: Elevation of the unit may be accomplished by construction a frame using suitable materials. If a support frame is constructed, it must not block drain holes in unit base.

When installed in areas where low ambient temperatures exist, locate unit so winter prevailing winds do not blow directly into outdoor coil.

Locate unit away from overhanging roof lines which would allow water or ice to drop on, or in front of, coil or into unit.

Slab Mounting

When installing a unit at grade level, install on slab high enough above grade so that water from higher ground will not collect around the unit (See Figure 2). Slab should have a slope tolerance away from the building of 2° or 2” per 5’. This will prevent ice from building up under the unit during a defrost cycle. Refer to following roof mounting section for barrier construction if unit must face prevailing winter winds.

Slab Mounting

Discharge Air

Building

Structure

Mounting Slab

Ground Level

Figure 2

Roof Mounting

Install unit at a minimum of 6” above surface of the roof to avoid ice buildup around the unit. Locate the unit above a load bearing wall or area of the roof that can adequately support the unit. Consult local codes for rooftop applications.

If unit coil cannot be mounted away from prevailing winter winds, a wind barrier should be constructed (See Figure 3). Size the barrier at least the same height and width as the outdoor unit. Mount barrier 24” from the sides of the unit in the direction of the prevailing winds.

Figure 3

Electrical Wiring

All field wiring must be done in accordance with the National Electrical Code (NEC) recommendations, Canadian Electrical Code (CEC) and CSA Standards, or local codes, where applicable.

Refer to the furnace or blower coil installation instructions for additional wiring application diagrams and refer to unit rating plate for minimum circuit ampacity and maximum overcurrent protection size.

WARNING

Unit must be grounded in accordance with national and local codes. Failure to ground unit properly can result in personal injury or death.

WARNING

Line voltage is present at all components when unit is not in operation on units with single pole contactors. Disconnect all remote electric power supplies before opening access panel. Unit may have multiple power supplies. Failure to disconnect all power supplies could result in personal injury or death.

506470-01

Issue 1007

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Contents Lennox International Inc. Company Save these instructions for future referenceTorque Table InstallationInstallation Clearances GeneralRoof Mounting Electrical WiringSlab Mounting Slab MountingRefrigerant Piping Installing Refrigerant LineRefrigerant Line Set Diameters PlacementOutside Unit Placement & Installation Line Set IsolationRefrigerant 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 Pressure Switch Circuit Defrost Control Timing PinsCompressor Delay Time DelaySystem 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 Indicating Light Fan SwitchSystem Switch Temperature IndicatorStart-Up and Performance Checklist Wire Diagram Issue