INSTALLATION INSTRUCTIONS

General Information

C33 and CX34 upflow evaporator coils are designed for use with air conditioner or heat pump units. C33 coils feature a factory-installed fixed orifice metering device and are available cased or uncased. CX34 coils include a factory-installed HFC-410A check (CTXV for heat pumps) or thermostatic (TXV for air conditioners) expansion valve (externally equalized) and are available only cased.

Refer to the Lennox Engineering Handbook for the proper use of these coils with Lennox furnaces, air conditioner units, heat pumps, and line sets.

These instructions are intended as a general guide and do not supersede local or national codes. Authorities having jurisdiction should be consulted before installation.

Warnings and Cautions

[Warning] Improper installation, adjustment, alteration, service, or maintenance can cause property damage, personal injury, or death. Installation and service must be performed by a qualified installer or service agency.

[Warning] Risk of explosion or fire. Can cause injury or death. Recover all refrigerant to relieve pressure before opening the system.

[Caution] Physical contact with metal edges and corners while applying excessive force or rapid motion can result in personal injury. Use caution when working near these areas during installation or servicing.

[Important] The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCs, HCFCs, and HFCs) as of July 1, 1992. Approved methods of recovery, recycling, or reclaiming must be followed. Fines and/or incarceration may be levied for non-compliance.

Table of Contents

• C33 and CX34 Series Coils
• General
• Shipping and Packing List
• Releasing Air Charge
• Unit Installation
• Refrigerant Line Set
• Replacement Parts
• Connections
• Refrigerant Metering Device
• Leak Testing, Evacuating and Charging
• Sealing Ducts
• Condensate Drain Connection
• Blower Speed Connection
• Maintenance

Shipping and Packing List

Package 1 of 1 contains the following:

For C33:

• 1 - Evaporator coil
• 1 - Patch plate with nameplate label (uncased coils only)
• 1 - Metering device label (uncased coils only)

For CX34:

• 1 - Evaporator coil

Check components for shipping damage. If damage is found, immediately contact the last carrier.

Unit Installation

Install the furnace or air handler according to the installation instructions provided with the unit.

Cased C33 or CX34 Coils:

Position the cased coil on top of the furnace or air handler cabinet and secure it using field-provided screws. Cased coils have six screw clearance holes that should align with the furnace engagement holes. Secure the coil casing using six field-provided #8 X 1" screws.

An optional adapter base is available for uncased coils (Lennox part no. 81J46 for single, 11L09 for a package of 10). See Figure 1: Adapter Base for illustration.

Figure 2: Field-Installed Coil Support illustrates how to place an uncased coil into the air duct. Note: C33-18A through C33-62C coils are positioned front-to-rear on the furnace cabinet. C33-60D and C33-62D are positioned left-to-right.

[Caution] The coil is shipped with dry air. Pierce a hole in the coil's rubber plug vapor line seal to relieve pressure before removing seals. The C33 and CX34 coils are shipped with a 15 ± 3 psi dry air holding charge. Ensure the coil is void of pressure by performing the following procedure:

1. Remove valve stem cap.
2. Press the liquid line valve stem.

Refrigerant Line Set

Size refrigerant line sets according to the air conditioner unit installation instructions. Use Table 2 or Table 3 to determine correct braze connection sizes. A field-provided adapter may be required.

Table 2. Refrigerant Line Connections - Model C33

Table 3. Refrigerant Line Connections - Model CX34

Replacement Parts

For replacement parts, order kit 69J46. The kit includes:

• 10 - Brass nuts for liquid line assemblies
• 20 - Teflon rings
• 10 - Liquid line orifice housings
• 10 - Liquid line assemblies

Connections: Use a silver alloy brazing rod (5 or 6 percent silver alloy for copper-to-copper connections or 45 percent silver alloy for copper-to-brass or copper-to-steel connections).

C33/CX34 - BRAZE SUCTION/VAPOR LINE

Procedure to connect the vapor line to the indoor coil unit:

1. Remove rubber plug.
2. Place a field-provided heat shield (e.g., wet rag) against the piping plate and around piping stubs. Sweat in the suction line. The heat shield protects paint from heat damage.
3. Braze connection.
4. Remove heat shield after brazing and allow connections to cool.

C33 - CONNECT LIQUID LINE

Procedure to connect the liquid line to the indoor coil unit:

1. Slide the liquid line compression nut onto the provided liquid line fitting (attached to the front of the delta plate of uncased coils).
2. Insert the field-supplied liquid line into the liquid line stub for brazing.

CX34 - CONNECT LIQUID LINE

Procedure to connect the liquid line to the indoor coil unit:

1. Place a field-provided heat shield (e.g., wet rag) against the piping plate and around piping stubs, and braze in the liquid line. The heat shield protects the metering device from heat damage.
2. Braze the brass seal assembly from the swedged copper liquid line on the coil; braze field-provided liquid line into the swedged connection.
3. Alternatively, cut the copper liquid line on a vertical or horizontal section. Use a field-provided coupling to join the field liquid line and coil liquid line connections.
4. Remove heat shield after brazing and allow connections to cool.

See Figure 6: Liquid Line Connections for illustrations.

Refrigerant Metering Device

C33 coils are shipped with a factory-installed fixed orifice. C33 coils are compatible with HFC-410A fixed orifice or TXV/CTXV metering devices. CX34 coils have factory-installed HFC-410A TXV/CTXV metering devices.

Determining Correct Fixed Orifice

A properly sized fixed orifice may be provided with the outdoor unit. Refer to the outdoor unit instructions for proper sizing. An improperly sized orifice can lead to diminished capacities, efficiencies, or unit damage. Orifices shipped with coils are identified in Table 1.

C33 - Typical Fixed Orifice Removal Procedure

1. On fully cased coils, remove coil access and plumbing panels.
2. Remove shipping clamps holding the liquid line and distributor assembly.
3. Using two wrenches, disconnect the liquid line from the distributor. Avoid twisting or damaging distributor tubes.
4. Remove and discard the orifice, valve stem assembly (if present), and Teflon ring. See Figure 8: Typical Fixed Orifice Removal.
5. Retain the brass nut for later use with the liquid line assembly.

C33 - Typical Fixed Orifice Installation Procedure

1. Ensure the orifice is installed with the nylon seat pointing toward the liquid line orifice housing.
2. Insert the Teflon ring securely into the liquid line orifice housing. Lightly lubricate the threads of the housing and the Teflon ring surface.
3. Connect the liquid line assembly with the brass nut to the liquid line orifice housing. Finger tighten, then use a wrench to turn an additional 1/2 turn clockwise (or 20 ft-lb). See Figure 7: Tightening Distance.
4. Place the supplied fixed orifice sticker on the indoor cabinet after installation.

See Figure 9: Typical Fixed Orifice Installation for illustration.

C33 - Typical TXV Installation Procedure

The TXV can be installed internal or external to the indoor coil. For uncased coils installed in a field-provided plenum, install the TXV for field servicing access. Refer to Figures 10 and 11 for installation.

1. Insert one Teflon ring into the stubbed end of the TXV. Lightly lubricate the TXV stubbed end threads and the Teflon ring surface.
2. Attach the TXV stubbed end to the liquid line orifice housing. Finger tighten, then use a wrench to turn an additional 1/2 turn clockwise (or 20 ft-lb).
3. Place the remaining Teflon washer around the other TXV end. Lightly lubricate threads and Teflon ring surface.
4. Attach the liquid line assembly with brass nut to the TXV. Finger tighten, then use a wrench to turn an additional 1/2 turn clockwise (or 20 ft-lb).
5. Attach the TXV sensing bulb to the suction line using the provided clamp and screws, ensuring proper orientation as shown in Figure 12: TXV Sensing Bulb Installation. Note: For lines smaller than 7/8", mount bulb at 3 or 9 o'clock. For 7/8" and larger lines, mount at 4 or 8 o'clock. Never mount on the bottom of the line.
6. Connect the TXV equalizer line to the equalizer suction port on the suction line. Finger tighten the flare nut plus 1/8 turn (7 ft-lbs).

[Important] To prevent water damage, properly insulate all parts of the TXV assembly that may sweat.

[Important] When removing the flare nut, ensure the copper flare seal bonnet is removed. See Figure 13: Copper Flare Seal Bonnet Removal.

TXV kits typically include: TXV, Teflon rings, copper mounting strap, hex head bolts, and nuts. See Figure 14: TXV Kit Components.

Leak Testing, Evacuating and Charging

Refer to the outdoor unit instructions for leak testing, evacuating, and charging procedures. Always leak check the entire system before charging.

Sealing Ducts

Ensure the duct is secured and all joints are properly sealed to either the coil cabinet flanges (fully cased models) or the furnace cabinet flanges (uncased models).

Condensate Drain Connections

C33(F) and CX34(F) coils have main and auxiliary drain connections. The auxiliary drain removes condensate if the main drain becomes plugged.

[Important] After removing the drain plug and before connecting the drain line, check the drain hole for an opening and ensure it is free of debris. Ensure the drain pan is clear of debris.

[Important] Auxiliary Drain Line: If the cooling coil is located above a finished space, install an auxiliary drain line (3/4" minimum) connected to a water-tight, corrosion-resistant pan beneath the indoor coil or to the secondary condensate drain outlet.

See Figure 15: Typical Condensate Drain Connection.

1. Install a trap in both drain lines per local codes. If a vent tee is required, install it between the unit outlet and the vent tee.
2. Make drain connections at the 3/4" female threaded pipe using lines of the same size. Pitch the main drain line down to an open drain or sump.
3. For the auxiliary drain line, remove the plug and route the line so water draining from it is easily noticed.
4. After removing drain pan plugs, check drain ports. If holes are not drilled, use a 19/32" bit for the primary drain hole and a 3/8" bit for the secondary drain hole. Remove all drill shavings.
5. Ensure drain ports and drain pan are free of debris.
6. Plug and check any unused drain pan openings for tightness (1/8 turn or 7 ft-lb) to prevent leaks.

Blower Speed Connection and Static Pressure Test

[Caution] Take care when drilling test holes into the furnace flange and duct. Drill holes away from refrigerant piping. Test holes should be drilled where specified to avoid unit damage.

Proper air volume must be provided over the evaporator coil. Select a blower motor speed tap that provides 400 ± 50 CFM per 12,000 Btuh of cooling capacity (wet coil). A static pressure reading must be taken to ensure the pressure drop is within the proper range. Air must be read from below and above the coil. See Figure 16: Static Pressure Test.

1. Drill one 5/16" (8 mm) air test hole into the delta plate between coil slabs.
2. Drill one 5/16" (8 mm) air test hole into the duct above the top of the coil.
3. Connect instrument hoses to the air entering side of the coil. Insert hoses 1/4" (6 mm) into the duct or end seal. Seal around holes with Permagum.
4. Turn on electrical power and set the thermostat to initiate a cooling demand.
5. Tables 4 and 5 list air volumes and equivalent static pressure readings. Observe the static pressure reading. Increase blower speed if below required air volume; decrease if above. Refer to furnace wiring diagram for settings.
6. When required static pressure readings are obtained, remove test hoses and insert snaphole plugs into test holes.

Table 4. Air Volume / Static Pressure Drop Across Coil - Model C33

Table 5. Air Volume / Static Pressure Drop Across Coil - Model CX34

Maintenance

[Caution] A damaged coil fin can affect equipment operation and performance. Do not use flame, high-pressure water, steam, or volatile cleaners on fins or tubing surfaces. If cleaning requires acidic or alkaline cleaners, follow manufacturer's instructions. Flush cleaner thoroughly from all components. Prevent damage or corrosion to connected components or surrounding areas.

A trained technician or service agency must perform maintenance and service. Indoor coils should be cleaned at the beginning of each heating or cooling season.

Do not use hydrofluoric acid, alkaline, or similar chemicals. Acid washes are used for oils and greases, which are generally not present. Alkaline washes dissolve oxides like zinc oxide, aluminum oxide, and iron oxide (rust), which can increase corrosion.

Cleaning the Coil:

1. Remove the coil from the cabinet or plenum and take it to an appropriate place for cleaning.
2. Vacuum or brush the coil to remove matted and surface debris from the fins. Use non-destructive vacuum attachments or brushes.
3. For oil deposits, spray the coil with ordinary household liquid detergent. Allow detergent to soften deposits for 10 minutes.
4. For coastal regions, fresh water will dissolve salt deposits. Wash coils with fresh water at least every six months.
5. Spray the coil at a vertical angle of 30 to 45 degrees with a constant stream of water at moderate pressure. A pressure washer with a fan nozzle is recommended. Do not spray from a horizontal direction.
6. Direct the spray to wash debris out of the coil and basepan. Hot water is not necessary for most residential units.

[Important] Ensure distributor lines are not rubbing together or kinked. All tubes must have clearance from other metal parts. Secure tubes with wire ties to prevent movement that could cause refrigerant tubing failure. Adjust tubes as necessary. Wires should never touch or be secured to refrigerant lines containing hot gas.