Lennox HS25–211

SERVICE
HS25
UNIT
INFORMATION

1993 Lennox Industries Inc.
Corp. 9327-L3 Litho U.S.A.
HS25 SERIES UNITS
The HS25 is a high efficiency residential split–system
condensing unit which features a scroll compressor. It
operates much like a standard condensing unit, but the
HS25’s scroll compressor is unique in the way that it
compresses refrigerant. Several models are available in
sizes ranging from 1–1/2 through 5 tons. The series is de-
signed for use with an expansion valve in the indoor unit.
This manual is divided into sections which discuss the
major components, refrigerant system, charging pro-
cedure, maintenance and operation sequence.
All specifications in this manual are subject to change.
SCROLL COMPRESSOR
DISCHARGE
SUCTION
ÎÎÎ
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I–APPLICATION
All major components (indoor blower/coil) must be
matched according to Lennox recommendations for
the compressor to be covered under warranty. Refer to
the Engineering Handbook for approved system
matchups. A misapplied system will cause erratic op-
eration and can result in early compressor failure.
II–SCROLL COMPRESSOR
The scroll compressor design is simple, efficient and
requires few moving parts. A cutaway diagram of the
scroll compressor is shown on the cover. The scrolls
are located in the top of the compressor can and the
motor is located just below. The oil level is immediate-
ly below the motor.
The scroll is a simple compression concept centered
around the unique spiral shape of the scroll and its in-
herent properties. Figure 1 shows the basic scroll form.
Two identical scrolls are mated together forming con-
centric spiral shapes (figure 2). One scroll remains sta-
tionary, while the other is allowed to orbit (figure 3).
Note that the orbiting scroll does not rotate or turn but
merely orbits the stationary scroll.

Lennox HS25–211 Specifications

General

Brand	Lennox
Model	HS25–211
Category	Air Conditioner
Language	English

Summary

III-UNIT COMPONENTS

Transformer Component

Details the transformer and its function in powering unit controls.

Contactor Function

Explains the contactor's role in energizing the compressor and fan motors.

TD1-1 Time Delay Operation

Describes the time delay function for compressor start-up and short-cycle prevention.

Compressor Specifications

Lists specifications for compressors used in HS25 series units.

Temperature Sensor Function

Explains the function and replacement of the compressor temperature sensor.

High Pressure Switch

Details the high pressure switch that shuts off the compressor when discharge pressure rises.

IV-REFRIGERANT SYSTEM

Refrigerant System Plumbing

Describes field refrigerant piping and connections for liquid and suction lines.

V-CHARGING THE SYSTEM

System Leak Testing Procedure

Details the procedure for leak testing the system using dry nitrogen.

System Evacuation Process

Explains the critical process of evacuating the system to remove non-condensables.

Refrigerant Charging Method

Outlines the recommended method for charging the unit with refrigerant by weight.

VI-MAINTENANCE PROCEDURES

Outdoor Unit Maintenance

Provides steps for cleaning and inspecting the outdoor unit components.

Indoor Coil Cleaning

Instructions for cleaning the indoor coil and checking for leaks.

Indoor Unit Checks

Steps for cleaning, filter replacement, and checking indoor unit electrical parameters.

VII-DIAGRAMS AND OPERATION

HS25 Unit Wiring Diagram

Presents the wiring diagram for the HS25 condensing units.

Cooling Operation Sequence

Describes the step-by-step electrical operation sequence for cooling demand.