Lennox CH35 Series Installation Instructions

Important Safety Information

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.

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.

General Information

CH35 all-aluminum coil horizontal evaporator coils are designed for use with air conditioners and heat pumps and are supplied with a factory-installed HFC-410A check/expansion valve.

The coil drain pan has a maximum service temperature of 500°F. The drain pan must be at least 2 inches away from a standard gas-fired furnace heat exchanger and at least 4 inches away from any drum-type or oil-fired furnace heat exchanger. Closer spacing may damage the drain pan and cause a leak.

Refer to the Product Specification bulletin (EHB) for the proper use of these coils with specific furnaces, outdoor units, and line sets.

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

Model Number Identification

The model number is constructed as follows:

Unit Type: CH = Indoor Coil, Horizontal

Series: CH35

Example Model Number: CH 35 - 18 A - 2 F

• Nominal Cooling Capacity: 18 = 1.5 tons, 24 = 2 tons, 30 = 2.5 tons, 36 = 3 tons, 42 = 3.5 tons, 48 = 3.5/4 tons, 50 = 4 tons, 51 = 4 tons, 60 = 5 tons.
• Cabinet: F = Cased
• Metering Device: 2 = Factory installed RFC
• Cabinet Height: A = 14-1/2 in., B = 17-1/2 in., C = 21 in., D = 24-1/2 in.

Specifications

1.5 TO 3 TON Models

3 ΤΟ 5 ΤΟΝ Models

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

The CH35 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.

Figure 1. Insulate Suction Line Inside Cabinet: A diagram shows foam tape applied to the suction line inside the cabinet.

1. Left-Hand and Right-Hand Discharge: The coil must have a 1/2 inch 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 inch 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 inch 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 CH35-60 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 2. D-Width Coil with C-Width Furnace: A diagram illustrates a D-width coil installed with a C-width furnace, highlighting the need for a block-off plate to cover the gap.

Figure 3. Left-Hand Air Discharge: Diagram shows a left-hand air discharge configuration with the coil, supply air unit, drain, plumbing connections, and indicates a 1/2 inch slope.

Figure 4. Right-Hand Air Discharge: Diagram shows a right-hand air discharge configuration. Note: This orientation is acceptable for 80% AFUE furnaces. Do not use this orientation for 90% condensing furnaces.

Figure 5. Right-Hand Air Discharge with Spacer: Diagram shows a right-hand air discharge with a field-provided spacer between the coil and the furnace, indicating a 1/2 inch slope.

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: A diagram displays the components included in kit 69J46, such as liquid line orifice housings, Teflon rings, brass nuts, piston retainer, strainer, and liquid line assemblies.

Brazing Guidelines

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).

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: A diagram illustrates the brazing process, showing a wet rag placed against the coil cabinet and around the suction line connection to protect it from heat.

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

The following practices are recommended to ensure better condensate removal:

• 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 the 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: This diagram illustrates main and overflow drain configurations, including options for secondary drain pans, overflow switches, vents, and traps. It notes that the vent must extend 2 inches above the coil drain pan and that traps should be deep enough to offset maximum static differences (generally, two inches). For negative pressure coils, traps are required on all drain lines connected to the coil. The drain line should slope a minimum of one inch per 10 feet.

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 to obtain an accurate reading.

Figure 9. Static Pressure Test: A diagram shows test hole locations on the coil case and supply air duct for measuring static pressure.

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 in order to avoid unit damage.

1. Drill a 5/16 inch test hole in the coil case 1 inch from the furnace flange (test hole 1, Figure 9).
2. Drill a 5/16 inch 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 inch 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.

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 50psi). If the coil cannot be cleaned using water alone, Lennox recommends 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.

Note: Attempting to back flush from the inside of the coil will require removing parts from the unit, and it may be very difficult to flush the whole coil surface. Attempting to blow water through a coil will slow the water stream and reduce the flushing action of the outer fin surface.

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.