Lennox HPXA12 SERIES User Manual

Page 1
©2002 Lennox Industries Inc.
Corp. 0208−L3
HPXA12
Service Literature
Revised 09−2004
HPXA12 SERIES UNITS
The HPXA12 is a high efficiency residential split−system
heat pump unit, which features a scroll compressor and
R410A refrigerant. HPXA12 units are available in sizes
ranging from 1 1/2 through 5 tons. The series is designed
for use with an expansion valve only (approved for use with
R410A) in the indoor unit.This manual is divided into sec-
tions which discuss the major components, refrigerant sys-
tem, charging procedure, maintenance and operation se-
quence.
Information contained in this manual is intended for use by
qualified service technicians only. All specifications are
subject to change.
IMPORTANT
Operating pressures of this R410A unit are higher
than pressures in R22 units. Always use service
equipment rated for R410A.
WARNING
Warranty will be voided if covered equipment is re-
moved from original installation site. Warranty will
not cover damage or defect resulting from:
Flood, wind, lightning, or installation and opera-
tion in a corrosive atmosphere (chlorine, fluorine,
salt, recycled waste water, urine, fertilizers, or oth-
er damaging chemicals).
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a qualified installer or service
agency.
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at discon-
nect switch(es). Unit may have multiple
power supplies.
TABLE OF CONTENTS
General 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications / Electrical 2. . . . . . . . . . . . . . . . . . . . . . . .
I Unit Information 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
II Unit Components 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
III Refrigerant System 13. . . . . . . . . . . . . . . . . . . . . . . . . .
IV Charging 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V Service and Recovery 19. . . . . . . . . . . . . . . . . . . . . . . .
VI Maintenance 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VII Wiring Diagram and Operating Sequence 20. . . . . .

Lennox HPXA12 SERIES Specifications

General

Brand	Lennox
Model	HPXA12 SERIES
Category	Heat Pump
Language	English

Summary

Unit Information and ESD Precautions

Electrostatic Discharge (ESD) Protection

Procedures to protect electronic components from electrostatic discharge during installation and service.

Control Box Configuration

Overview of single and three-phase unit control boxes, including terminal strips.

Unit Components: Electrical and Controls

Compressor Contactor, Fan Relay, and Capacitors

Details on contactors, relays, fan motors, and capacitors.

Demand Defrost System and Features

Explains the defrost board, its logic, lockout features, and diagnostic LEDs.

Pressure Switches and Lockout Conditions

Covers HI-PS/LO-PS terminals and strike lockout conditions for defrost control.

Unit Components: Mechanical and Refrigerant Path

Scroll Compressor and Fan Motor

Information on scroll compressor design, three-phase rotation, and outdoor fan motor.

Reversing Valve, Drier, and Pressure Switches

Details on reversing valve, filter drier, and high/low pressure switch functions.

Refrigerant System and Plumbing

Cooling and Heating Cycle Flow Diagrams

Diagrams illustrating refrigerant flow in cooling and heating modes with gauge connections.

Plumbing, Line Sets, and Service Valves

Details on refrigerant piping, line sets, and service valve functions.

Charging and Evacuation Procedures

Leak Testing and System Evacuation

Steps for leak testing, using nitrogen, and evacuating the system to remove noncondensables.

Refrigerant Charging Methods

Procedures for charging based on temperature, subcooling, or approach methods.

Service and Maintenance

Service Precautions and Refrigerant Recovery

Precautions for preventing moisture entry during service and recovery of R410A.

Annual Maintenance Checks

Procedures for inspecting and maintaining outdoor and indoor units.

Wiring Diagrams and Operation Sequence

Single Phase Wiring Diagram

Detailed wiring diagram for single-phase HPXA12 units.

Three Phase Wiring Diagrams

Wiring diagrams for three-phase HPXA12 units (230V and 460V).

Operating Sequence Explanation

Step-by-step explanation of cooling, heating, and defrost modes.