Lennox CHX35 Series Indoor Coils Installation Instructions

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.

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 noncompliance.

CAUTION

As with any mechanical equipment, contact with sharp sheet metal edges can result in personal injury. Take care while handling this equipment and wear gloves and protective clothing.

IMPORTANT: Special procedures are required for cleaning the aluminum coil in this unit. See page 7 in this instruction for information.

Shipping and Packing List

Package 1 of 1 contains:

• 1 - Evaporator coil

Check the components for shipping damage; if found, immediately contact the last carrier.

INSTALLATION INSTRUCTIONS

CHX35 Series Coils

INDOOR COILS

Model Number: 507835-01 (067198001)

Date: 11 / 2021

Model Number Identification

The model number is identified by a series of codes indicating unit type, refrigerant type, series, nominal cooling capacity, metering device, cabinet width, and cabinet type.

Example: CHX35-18A-6F

• CHX = Indoor Coil - Horizontal
• 35 = Series
• 18 = Nominal Cooling Capacity (1.5 tons)
• A = Cabinet Width (14-1/2 inches)
• 6 = Metering Device (Factory-Installed Check/Expansion Valve for HFC-410A Refrigerant)
• F = Cabinet (Cased)

Note: Furnaces with the same cabinet width letter designation will physically match the corresponding indoor coil.

Specifications

Releasing Air Charge

CAUTION: The coil is shipped from the factory pressurized with dry air. Pierce a hole in the rubber plug that seals the vapor line to relieve the pressure before removing the plugs.

NOTE: If there is no pressure released when the vapor line rubber plug is pierced, check the coil for leaks before continuing with the installation.

The CHX35 coils are shipped with a 9 ± 2 psi dry air holding charge. Puncture the suction line rubber plug to release the charge. Remove the rubber plug. Ensure that the coil is void of pressure.

Installation

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

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

NOTE: In areas of high humidity, use foam tape to insulate the suction line section in the cabinet as shown in Figure 1.

1. Left-Hand and Right-Hand Discharge

The coil must have a 1/2" slope from the rear of the cabinet to the drain. Position the coil adjacent to the furnace cabinet and align the six screw clearance holes in the coil casing with the furnace engagement holes. Use six field-provided #8 X 1" screws to secure the coil casing to the furnace (see Figures 3 and 4).

2. Right-Hand Air Discharge with Field-Provided Spacer

The coil must have a 1/2" slope from the rear of the cabinet to the drain. Position the coil in the left-to-right configuration on the service access side of the furnace. Insert a field-provided spacer between the furnace and the coil. Use field-provided screws to secure the coil casing, spacer, and the furnace together. The spacer should be long enough to allow room for proper installation (approximately 6 inches minimum). See Figure 5.

NOTE: When the coil is connected directly with a condensing furnace, the coil must be level from return end to supply end. The front (access side) of the furnace may be pitched downward up to 1 inch to accommodate a 1/2-inch pitched coil.

3. Secure the supply duct to the coil cabinet.

4. Refer to the instructions provided with the condensing unit for leak testing, evacuating, and charging procedures. Always check the entire system for leaks before charging.

5. Applications using CHX35-60 D-width unit with C-width furnace

Figure 2 shows an application that includes a D-width coil and a C-width furnace. This application requires construction of an insulated, field-supplied block-off plate to cover the open space on the coil housing.

Figure 1: Insulate Suction Line Inside Cabinet - Shows foam tape applied to the suction line within the cabinet for humidity control.

Figure 2: D-Width Coil with C-Width Furnace - Illustrates the use of a field-fabricated insulated block-off plate for a D-width coil with a C-width furnace, showing air flow direction and test hole placement.

Figure 3: Left-Hand Air Discharge - Depicts the left-hand air discharge configuration with a 1/2" slope towards the coil drain, showing top and end views, and the supply air unit connection.

Figure 4: Right-Hand Air Discharge - Shows the right-hand air discharge configuration with a 1/2" slope towards the coil drain, including top and end views, and notes on suitability for 80% AFUE furnaces.

Figure 5: Right-Hand Air Discharge with Spacer - Illustrates the right-hand air discharge setup using a field-provided spacer between the furnace and the coil.

Refrigerant Line Connections

LINE SIZES

The refrigerant line sets should be sized according to the recommendations given in the air conditioner or heat pump unit installation instructions. Use Table 1 to determine correct braze connection sizes. A field-provided adapter may be required to match line set connections.

REPLACEMENT PARTS

If replacement parts are necessary, 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

Figure 6: 69J46 Kit Components - Shows the individual parts included in the replacement kit for liquid line assemblies.

BRAZING GUIDELINES

Use a silver alloy brazing rod (5% or 6% silver alloy for copper-to-copper connections or 45% silver alloy for copper-to-brass or copper-to-steel connections). Before making brazed connections, place a field-provided heat shield, such as a wet rag, against the unit cabinet and around the piping stubs, expansion valve, and sensing bulb (or remove the sensing bulb temporarily). The heat shield must be in place to prevent heat damage during brazing. See Figure 7.

Figure 7: Braze Refrigerant Lines - Illustrates the process of brazing refrigerant lines, showing the use of water-saturated rags as heat shields for the suction line connection and TXV sensing bulb.

SUCTION LINE CONNECTION

1. Remove rubber plug from the stubbed connection.
2. Position the properly sized refrigerant piping and make the brazed connection following the brazing guidelines.
3. Do not remove the water-saturated rags from the cabinet and piping until the piping has cooled completely.

LIQUID LINE CONNECTION

1. Remove rubber plug from the stubbed connection.
2. Position the properly sized refrigerant piping and make the brazed connection following the brazing guidelines.
3. Do not remove the water-saturated rags from the cabinet and piping until the piping has cooled completely.

Leak Testing, Evacuating and Charging

Refer to the outdoor unit instruction 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 the coil cabinet flanges.

WARNING: There must be an airtight seal between the bottom of the air handler and the return air plenum. Use fiberglass sealing strips, caulking, or equivalent sealing method between the plenum and the air handler cabinet to ensure a tight seal. Return air must not be drawn from a room where this air handler or any gas-fueled appliance (i.e., water heater) or carbon monoxide-producing device (i.e., wood fireplace) is installed.

IMPORTANT: DUCT SYSTEM SIZING - The duct system should be properly sized and installed according to the ASHRAE Standard Manual D. The supply and return air duct systems should be designed for the CFM and static requirements of the job. Consult the blower performance chart in the unit installation instructions to verify that the blower meets the application requirements.

Condensate Drain Connections

IMPORTANT: After removal of drain pan plug(s), check drain hole(s) to verify that the drain opening is fully open and free of any debris. Also, check to make sure that no debris has fallen into the drain pan during installation that may plug up the drain opening.

MAIN DRAIN

Connect the main drain and route downward to a drain line or sump. Do not connect the drain to a closed waste system. See Figure 8 for typical drain trap configuration.

OVERFLOW DRAIN

It is recommended that the overflow drain is connected to an overflow drain line for all units. If the overflow drain is not connected, it must be plugged with the provided cap.

BEST PRACTICES

• Main and overflow drain lines should NOT be smaller than drain connections at the drain pan.
• Overflow drain line should run to an area where a homeowner will notice drainage.
• It is recommended that the overflow drain line be vented and a trap installed. Refer to local codes.

Figure 8: Typical Main and Overflow Drain Installations - Shows recommended configurations for main and overflow drain lines, including trap installations and vent requirements.

Blower Speed Selection

Proper air volume must be provided over the evaporator coil. Select a blower motor speed tap that will provide 400 ± 50 CFM per 12,000 Btuh of cooling capacity (wet coil). A static pressure reading must be taken to see if the pressure drop falls within the proper range.

To ensure accuracy, static pressure must be read from the air entry side of the coil to the air exit side of the coil. See Figure 9 for an example of how to obtain an accurate reading.

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

1. Drill a 5/16" test hole in the coil case 1" from the furnace flange (test hole 1, Figure 9).
2. Drill a 5/16" test hole into the supply air duct (test hole 2, Figure 9).
3. Connect the zero end of the draft gauge scale to the furnace end of the coil. Insert the hoses so that 1/4" extends inside the duct or end seal. Seal around holes with Permagum.
4. Turn on electrical power to the furnace and set the thermostat to initiate a cooling demand.
5. Table 2 lists the range of air volumes and equivalent draft gauge readings for this unit. Observe the draft gauge reading. If the reading is below the required air volume, increase the blower speed; if the reading is above the required air volume, decrease the blower speed. Refer to the furnace wiring diagram for blower speed settings.
6. When the required draft gauge readings are obtained, remove the draft gauge lines and insert snaphole plugs into the test holes.

Figure 9: Static Pressure Test - Details the procedure for measuring static pressure across the coil using test holes and a draft gauge, showing the placement of test holes 1 and 2.

Maintenance

NOTICE! Failure to follow instructions will cause damage to the unit.

This unit is equipped with an aluminum coil. Aluminum coils may be damaged by exposure to solutions with a pH below 5 or above 9. The aluminum coil should be cleaned using potable water at a moderate pressure (less than 50 psi). If the coil cannot be cleaned using water alone, Lennox recommends the use of a coil cleaner with a pH in the range of 5 to 9. The coil must be rinsed thoroughly after cleaning.

A trained technician or service agency must perform maintenance and service on equipment. At the beginning of each heating or cooling season, indoor coils should be inspected to determine whether the coil requires cleaning.

CLEANING THE COIL

1. Remove the coil from the cabinet or plenum, and take the coil to an appropriate place to clean it.
2. Vacuum or brush the coil to remove matted and surface debris from the fins. Use vacuum attachments and/or brushes that are non-destructive to fins.
3. If oil deposits are present, spray the coil with a mild coil cleaner with a pH in the range of 5 to 9 to soften deposits. Do not leave the coil cleaner on the coil for more than 10 minutes. Flush the coil thoroughly with potable water.
4. 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 will work best. Do not spray the coil from a horizontal direction.
5. Direct the spray so that any debris is washed out of the coil. For most residential units, hot water is not necessary.
6. Replace the coil into the cabinet or plenum. Ensure that you have followed the proper procedure for routing and securing the refrigerant tubing.

IMPORTANT: Ensure that the distributor lines are not rubbing together or kinked. All tubes must have enough clearance from other metal parts. Use wire ties to secure tubes to prevent movement that could cause the refrigerant tubing to fail.