Lennox 10ACC-030-230 - User Manual

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Summary

10 ACC Series Unit Overview

10 ACC Series Unit Introduction

Details the 10ACC residential split-system condensing unit, its sizes, SEER rating, and compressor types.

Critical Safety Warnings

Highlights critical warnings regarding refrigerant handling, electrical shock, and general safety for installation and service.

Electrical and Specification Data

Electrical Data Summary

Presents electrical specifications including voltage, ampacity, fuse size, and motor ratings for 10ACC models.

Unit Specifications

Details unit specifications like tonnage, refrigerant connections, coil size, fan motor, and weights for 10ACC models.

Optional Accessories

Lists optional accessories available for the 10ACC series units, such as crankcase heaters and hail guards.

General Information and Unit Components

General Safety and Unit Description

Covers general safety warnings and an overview of major unit components illustrated in Figure 1.

Control Box Diagrams

Illustrates the control box for reciprocating and scroll compressors, showing key components like contactors and capacitors.

Control Box Components

Compressor Contactor (K1)

Explains the function and operation of the compressor contactor (K1) in the 10ACC unit's control box.

Capacitors and Relays

Details the dual capacitor (C12), start capacitor (C7), and potential relay (K31) used in the 10ACC control box.

Scroll Compressor Operation

Scroll Compressor Design and Function

Explains the design, operation, and unique compression concept of the scroll compressor used in 10ACC units.

Scroll Compressor Precautions

Describes how the scroll compressor compresses gas and warns against using it for evacuation due to potential damage.

Condenser Fan Motor

Condenser Fan Motor Function

Explains that the condenser fan motor uses a run capacitor and is controlled by the compressor contactor.

Condenser Fan Motor Access

Details how to access the condenser fan motor assembly and replace the motor, referencing Figures 8 and 9.

Refrigerant System and Service

Refrigerant System Plumbing

Covers field refrigerant piping, line set types, and connection sizes for the 10ACC series.

Service Valve Operation

Explains how to operate liquid and suction line service valves, including accessing the Schrader port and closing the valve.

Charging Procedures

Ball Type Suction Line Service Valve

Describes the ball-type full service valve used on 5-ton units and its service port.

Pumping Down and Leak Testing

Details the process for pumping down the system and performing leak testing before evacuation.

System Evacuation and Charging

System Evacuation Process

Step-by-step guide for evacuating the system to the required vacuum level, including precautions.

Refrigerant Charging Methods

Explains factory charge, adjustments for line set length, and methods based on outdoor temperature.

Charging Techniques

Weighing Charge for Fixed Orifice;TXV

Guidance on weighing refrigerant charge for fixed orifice or TXV systems, especially in cool weather.

Subcooling Method for Fixed Orifice

Details how to use the subcooling method to charge fixed orifice systems when outdoor temp is above 65°F.

Approach Method for TXV Systems

Explains using the approach method for TXV systems when outdoor temperature is 60°F or above.

Maintenance Checks

System Pressure Checks

Guidance on using Table 5 for performing maintenance checks on system pressures and potential issues.

Condenser and Evaporator Coil Maintenance

Instructions for cleaning and inspecting condenser and evaporator coils, including condensate pan.

Indoor Unit Maintenance

Covers cleaning filters, adjusting blower speed, checking belts, wiring, voltage, and amp-draw.

Wiring Diagrams and Operation Sequence

10 ACC Operating Sequence

Details the sequence of operation for cooling mode, including thermostat demand and component activation.

Wiring Diagram Components

Identifies key components in the wiring diagram, such as capacitors, contactors, and motors.

The Lennox 10ACC is a residential split-system condensing unit designed for cooling applications. It is available in various sizes, ranging from 1-1/2 to 5 tons, and is engineered to achieve a minimum SEER rating of 10.0. The unit is compatible with either an expansion valve or an RFCIV system in the indoor unit.

Function Description:

The 10ACC unit's primary function is to provide cooling for residential spaces. It operates as part of a split-system, meaning it works in conjunction with an indoor evaporator coil and blower. The condensing unit, located outdoors, compresses and condenses refrigerant, which then circulates to the indoor coil to absorb heat from the indoor air, thus providing cooling.

Important Technical Specifications:

Capacities: Available in 1-1/2, 2, 2-1/2, 3, 3-1/2, 4, and 5 ton capacities.
Compressor Types:
- 10ACC 1-1/2 to 3 ton units are equipped with hermetically sealed reciprocating compressors. These compressors are mounted on resilient rubber to minimize vibration and noise, and include a built-in protection device against excessive current and temperatures.
- 10ACC 3-1/2 to 5 ton units feature scroll compressors, which are known for their efficiency and simple compression concept. Scroll compressors are tolerant to liquid return, as the orbiting scroll can separate from the stationary scroll to discharge liquid.
Refrigerant: Uses HCFC-22 refrigerant. The factory charge is sufficient for a 20 ft. (6.1 m) length of refrigerant lines. Specific charge amounts vary by model and are listed on the unit nameplate.
Electrical Data:
- Line voltage: 208/230V-1ph, 60Hz.
- Minimum circuit ampacity and maximum fuse sizes vary by model (e.g., 10ACC-018: 11.6 amps min. circuit, 20 amps max fuse; 10ACC-060: 35.5 amps min. circuit, 60 amps max fuse).
- Compressor rated load amps and locked rotor amps vary significantly by model.
- Condenser fan motor full load amps and locked rotor amps are also specified for each model.
Condenser Coil: Net face area, tube diameter (5/16 in. / 7.9 mm), number of rows (1), and fins per inch (22 / 866) are consistent across most models, though face area varies.
Condenser Fan: Diameter (16 in. / 406 mm to 22 in. / 559 mm), number of blades (3 or 4), motor horsepower (1/10 to 1/3 hp), CFM (L/s), RPM, and Watts vary by model.
Service Valves: Liquid line and suction line service valves are provided with sweat connections. Ball-type service valves are used on 5-ton units. Schrader valves are factory installed in service ports for leak testing, evacuation, and charging.
Control Box Components: Includes a compressor contactor (K1) and a dual capacitor (C12) for both the fan motor and compressor. Optional start capacitor (C7) and potential relay (K31) are used in reciprocating compressor units for enhanced starting.

Usage Features:

System Matching: Proper matching of indoor blower and coil with the condensing unit is crucial for warranty coverage and optimal operation. Refer to the Engineering Handbook for approved system matchups.
Charging Procedures:
- Weighing in the Charge: Recommended for systems void of refrigerant or when outdoor ambient temperature is below 60°F (16°C).
- Subcooling Method: Used for fixed orifice systems when outdoor ambient temperature is 65°F (18°C) or above. Requires measuring liquid line temperature and pressure.
- Approach Method: Used for TXV (Thermostatic Expansion Valve) systems when outdoor ambient temperature is 60°F (16°C) or above. Requires measuring liquid line temperature and outdoor ambient temperature.
Deep Vacuum Operation: Scroll compressors are capable of drawing a deeper vacuum than reciprocating compressors. However, deep vacuum operation (compressor operating at 0 psig or lower) should be avoided as it can cause internal fusite arcing and compressor failure. The compressor should never be used for evacuating or "pumping-down" the system.
Service Valve Operation: Instructions are provided for opening and closing liquid and suction line service valves, as well as accessing schrader ports for gauge manifold connection.
Electrical Controls: The unit's 24 VAC controls are powered by the indoor unit, as 10ACC units are not equipped with a 24V transformer.
Wiring: Detailed wiring diagrams and sequence of operation are provided for cooling cycles, including initiation and termination of cooling demand.

Maintenance Features:

Regular Checks: At the beginning of each cooling season, the system should be checked by a qualified installer or service agency.
Condenser Coil Cleaning: The condenser coil should be cleaned and inspected. It can be flushed with a water hose after ensuring power is off.
Leak Inspection: Visually inspect connecting lines and coils for evidence of oil leaks.
Electrical System Checks:
- Check wiring for loose connections.
- Verify correct voltage at the unit (when operating).
- Measure compressor and condenser fan motor amp-draw.
Refrigerant Charge Verification: If insufficient cooling is reported, the refrigerant charge should be checked using gauges and the appropriate charging method.
Evaporator Coil Maintenance: Clean the evaporator coil if necessary, check connecting lines and coils for oil leaks, and clean the condensate pan line.
Indoor Unit Maintenance: Clean or change filters, adjust blower speed for cooling (refer to service manual for pressure drop tables), check belt wear and tension for belt-drive blowers, and check wiring and voltage.

Safety Warnings:

Electrical Shock Hazard: Always disconnect all electrical power to the unit at the disconnect switch(es) before performing any service or maintenance. Units may have multiple power supplies. One leg of compressor, capacitor, and condenser fan are always connected to line voltage.
Refrigerant Handling: Refrigerant can be harmful if inhaled. It must be used and recovered responsibly.
Nitrogen Pressure: When using dry nitrogen for leak testing, a pressure-reducing regulator must be used to prevent excessive pressure in the gauge manifold, hoses, and system. Regulator setting must not exceed 150 psig (1034 kPa).
Service Valve Backseating: Do not attempt to backseat the service valves, as this can cause the snap ring to explode under refrigerant pressure, leading to personal injury and unit damage.
Qualified Personnel: Improper installation, adjustment, alteration, service, or maintenance can cause property damage, personal injury, or loss of life. Installation and service must be performed by a qualified installer or service agency.