LENNOX CBX25UH Upflow/Horizontal Air Handler Instruction Manual

LENNOX CBX25UH Upflow/Horizontal Air Handler

Safety

WARNING 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 licensed professional HVAC installer or equivalent, service agency, or the gas supplier. Use of this unit as a construction heater or air condition-er is not recommended during any phase of construction. Very low return air temperatures, harmful vapors and op-eration of the unit with clogged or misplaced filters will damage the unit.
If this unit has been used for heating or cooling of build-ings or structures under construction, the following condi-tions must be met or the warranty will be void:

• The vent hood must be installed per these installation instructions.

•  A room thermostat must control the unit. The use of fixed jumpers that will provide continuous heating or cooling is not allowed

• A pre-filter must be installed at the entry to the return air duct.

• The return air duct must be provided and sealed to the unit.

• Return air temperature range between 55°F (13°C) and 80°F (27°C) must be maintained.

• Air filters must be replaced and pre-filter must be removed upon construction completion.

• The input rate and temperature rise must be set per the unit r ating plate.

• The heat exchanger, components, duct system, air filters and evaporator coil must be thoroughly cleaned following final construction clean-up.

• The unit operating conditions (including airflow, cooling op-eration, ignition, input rate, temperature rise and venting) must be verified according to these installation instructions.
  NOTE – The Commonwealth of Massachusetts stipulates these additional requirements:

• Gas units shall be installed by a licensed plumber or gas fitter only.

•  The gas cock must be “T handle” type. The unit is certified for installation on noncombustible floors only. However, it may be installed on wood flooring, or on class A, class B, or class C material covered floors when used in horizontal discharge applications or in downflow discharge applications when mounted on an LARMF roof mounting frame.
  Adequate clearance shall be provided around air openings into the vestibule area. Provisions shall be made for proper operation and for combustion air and ventilation air supply. Unit must be adjusted for the temperature rise range and within the allowable external static pressure on furnaces with a duct system as listed on unit nameplate.

United States The unit is ETL/CSA certified for outdoor installations only at the clearances to combustible materials listed on the unit nameplate and in.

1Unit

Clearance

| A

in.(mm)

| B

in.(mm)

| C

in.(mm)

| D

in.(mm)

| Top Clearance
---|---|---|---|---|---
036, 060

Service Clearance

| 48

(1219)

| 36

(914)

| 60

(1524)

| 60

(1524)

| ****

Unobstructed

120

Service Clearance

| 60

(1524)

| 36

(914)

| 60

(1524)

| 60

(1524)

| ****

Unobstructed

240

Service Clearance

| 72

(1829)

| 36

(914)

| 60

(1524)

| 96

(2438)

| ****

Unobstructed

Clearance to| 36| 1| 1| 1| Unobstructed
Combustibles| (914)| (25)| (25)| (25)
Minimum Oper-| 36| 36| 36| 36| Unobstructed
ation Clearance| (914)| (914)| (914)| (914)

Note – Entire perimeter of unit base requires support when ele-vated above mounting surface.
Service Clearance – Required for removal of serviceable parts.
Clearance to Combustibles – Required clearance to combustible material. Minimum Operation Clearance – Required clearance for proper unit operation.
Installation of the ETL/CSA certified units must conform with local building codes. In the absence of local codes, units must be installed according to the current National Fuel Gas Code ANSI Z223.1/NFPA 54.
When installed, the unit must be electrically wired and grounded according to local codes or, in the absence of local codes, with the current National Electric Code, ANSI/NFPA 70.
The current American National Standard (ANSIZ233.1/ NFPA54) National Fuel Gas Code is available from the following address:

• American National Standard Institute Inc.
• 11 West 42nd Street
• New York, NY 10036

The current National Electric Code (ANSI/NFPA 70) is available from the following address:

• National Fire Protection Association
• 1 Batterymarch Park
• PO Box 9101
• Quincy, MA 02269-9101
• SGH036-240 Agency

Use only the type of gas approved for use with this furnace. Refer to unit nameplate.
Never test for gas leaks with an open flame. Check all connections with a commercially available soap solution made specifically for leak detection.
NOTE – Furnace must be adjusted to obtain a temperature rise (high and low fire) within the range(s) specified on the unit nameplate. Failure to do so may cause erratic limit operation.
Canada
The unit is CSA International (CSA) certified for combination heating/cooling for outdoor installations and non-residential use only at the clearances to combustible materials as listed on the unit nameplate. Installation of CSA international certified units must conform with current standard CSA B149.1, “Natural Gas and Propane Installation Codes” and applicable local codes. Authorities having jurisdiction should be consulted before installation. The unit must be wired and electrically grounded according to local codes or, in the absence of local codes, current CSA Standard C22.1 Canadian Electrical Code Part 1. Installation of combination heating/cooling units must also conform with current CSA Standard B52 “Mechanical Refrigeration Code.”

Connect Gas Piping

A manual main shut-off valve must be installed external to the unit when local codes require the installation of such a valve.
Install a ground joint union between the gas control manifold and the main manual shut-off valve. When making piping connections a drip leg should be installed on vertical pipe runs to serve as a trap for sediment or condensate. A 1/8” N.P.T. plugged tap is located on gas valve for test gauge connection. See Figure 2 or 3 for tap location. See Figure 4 for gas supply piping entry through the side of the unit and Figure 5 for gas piping through the bottom of the unit. A kit is required when routing gas supply piping through the bottom of the unit.
Compounds used on threaded joints of gas piping must be resistant to the actions of liquified petroleum gases.

High Alititue Derate

Locate the high-altitude conversion sticker in the unit literature bag. Fill out the conversion sticker and affix next to the unit nameplate. Refer to table 1 for high altitude adjustments.

*Units installed at 0-2000 feet do not need to be modified. NOTE – This is the only permissible derate for these units.

Pressure Test Gas Piping

Operating pressures at the unit gas connection must be as shown in table 2.

TABLE 2

OPERATING PRESSURE AT GAS CONNECTION “w.c.
Natural Gas| LP/ Propane Gas
Min.| Max.| Min| Max.
4.5| 10.5| 11| 13

When testing the pressure of gas lines, the gas valve must be disconnected and isolated. Gas valves can be dam-aged if subjected to more than 0.5 psig.

WARNING FIRE OR EXPLOSION HAZARD Failure to follow the safety warnings exactly could result in serious injury, death or property damage. Never test for gas leaks with an open flame. Use a commercially available soap solution made specifically for the detection of leaks to check all connections. A fire or explosion may result causing property damage, personal injury or loss of life.

Two-Stage Gas Valve Adjustment

Gas manifold pressures should match pressures shown in table 3. On two-stage gas valves, initiate a W2 thermostat demand to check high fire pressure before low fire pres-sure. With high fire operating, reduce the thermostat de-mand to W1 and check the low fire pressure. Refer to the Unit Controller manual to initiate a thermostat demand.
IMPORTANT – Do not set low fire pressure lower than the certified minimum input rating listed in table 3. TABLE 3 MANIFOLD INPUT PRESSURES in.wg. (kPa)

__

Unit

| Natural Gas| Propane (LP) Gas
---|---|---
1st Stage

± 0.2

| 2nd Stage

± 0.3

| 1st Stage

± 0.2

| 2nd Stage

± 0.3

036, 060| 2.0 (0.50)| 3.5 (0.87)| 5.9 (1.47)| 10.5 (2.61)
120, 240| 1.6 (0.40)| 3.7 (0.92)| 5.5 (1.37)| 10.5 (2.61)

Gas Heat Operation

See the operating instruction plate on the unit for details

Proper Gas Flow (Approximate)

1. Operate unit at least 15 minutes before checking gas flow. Determine the time in seconds for two revolutions of gas through the meter. (Two revolutions assures a more accurate time.) A portable LP gas meter (17Y44) is available for LP applications.
2. Divide the number of seconds by two and compare to the time in table 4. If manifold pressure is correct and rate is incorrect, check gas orifices for proper size and restriction.
3. Remove temporary gas meter if installed.
   NOTE – To obtain accurate reading, shut off all other gas appliances connected to meter.

TABLE 4 GAS METER CLOCKING CHART

NOTE – Table assumes standard temperature (60°F), pressure (30in.Hg.), and fuel heating values (Btuh/Ft.3). Apply pressure corrections in alti-tudes above 2000 ft.

Typical Gas Heat Schematic

This schematic is typical. See the wiring schematic on the unit for actual unit wiring.

Typical Unit Schematic

This schematic is typical. See the wiring schematic on the unit for actual unit wiring.

Repair Parts Listing

When ordering repair parts, include the complete model number and serial number listed on the ETL/CSA rating plate – e.g. SGH240H4MH1Y.

Gas Heat Section Parts

• Heat Exchanger
• Combustion Air Assembly
• Combustion Air Proving Switch
• Burner Assembly
• Burner Manifold Assembly
• Main Burner Orifices
• Flame Roll-out Switches
• Auxiliary Limit Controls
• Ignition Electrode
• Assembly Ignition Lead
• Ignition Sensor
• Assembly Sensor Lead
• Combination Gas Valve
• Limit Controls

Cooling Parts

• Compressors
• Low Pressure switch
• High Pressure Switch
• Condenser Fan Motors Condenser Fan Blades Condenser Fan Run Capacitors Freezestats
• Low Ambient Pressure Switch Low Ambient Thermostat Condenser Fan Mounting Bracket Fan Grille
• Indoor Blower Motors
• Blower Wheel
• Expansion Valve
• Distributor
• Crankcase Heaters
• Exhaust Fans (Opt.)

Electrical Control Parts

• Main Control Panel
• Economizer Control Panel (Opt.)
• Compressor 2 Control Panel
• Compressor 3 and 4 Control Panel
• Gas 2 Control Panel
• Compressor Contactors
• Circuit Breakers (Opt.)
• Transformer (Control)
• Transformer (Contactor)
• Transformer (CAB)
• Blower Contactor
• Limit, Blower Relay
• Heat Relays
• Condenser Fan Relays
• Capacitor CAB
• Relay CAB
• Low Ambient Relay
• Low Amb. Low-Pressure
• Switches Disconnect (opt.)
• Blower Motor Inverter

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