Standard ECM Single Piece Multi-Position Air Handlers

List of Sections

• General
• Safety
• Unit Installation
• Duct Work and Connections
• Coil Metering Devices
• Refrigerant Line Connection
• Condensate Drain Connections
• Electric Heater Installation
• Line Power Connections
• Low Voltage Control Connections
• Blower Speed Connections
• Unit Data
• Maintenance
• Air System Adjustment
• Installation Verification
• Wiring Diagram
• Typical Thermostat Connections
• Start Up Sheet

Section I: General

The single piece air handler series provides flexibility for installation in any position, including upflow, downflow, horizontal right, or horizontal left applications. These units can be located in closets, utility rooms, attics, crawl spaces, or basements. They are versatile and can be used for cooling or heat pump operation, with or without electric heat. Top or side power and control wiring, color-coded leads, and electric heaters simplify installation and minimize costs. Electric heat kits are available as field-installed accessories, with single-phase kits ranging from 2.5 kW to 25 kW, and 208-230 volt three-phase kits from 10 kW to 25 kW.

Section II: Safety

This section contains important safety information. Always pay attention to signal words like DANGER, WARNING, and CAUTION. DANGER indicates an imminently hazardous situation that could result in death or serious injury if not avoided. WARNING indicates a potentially hazardous situation that could result in death or serious injury if not avoided. CAUTION indicates a potentially hazardous situation that could result in minor or moderate injury if not avoided, and is also used to alert against unsafe practices or property damage.

FIRE OR ELECTRICAL HAZARD: Failure to follow safety warnings can result in serious injury, death, or property damage. Ensure proper installation and maintenance to prevent fire or electrical hazards.

WARNING: The air handler area must not be used for storage, as this can create a fire hazard. Never store items like aerosol cans, flammable liquids, cleaning supplies, or paper products near the unit. Never operate the air handler with the blower door removed, as this can cause serious injury or equipment damage.

CAUTION: Do not lift the air handler by the cabinet braces, as they may become disengaged, causing the unit to fall. Lift by gripping the casing. Maintain clearances for servicing and ensure electrical components are protected from water. Installation and servicing should only be performed by trained and licensed personnel. Unlicensed personnel may perform basic maintenance like cleaning and filter replacement. Always follow safety precautions outlined in manuals and on unit labels.

CAUTION: Transport and handle air handlers in an upright, upflow position to prevent unit damage and personal injury. Configuration conversions should be done at the site of installation.

These instructions cover minimum requirements and conform to existing national standards and safety codes. They may exceed certain local codes and ordinances.

Section III: Unit Installation

NOTICE: Avoid handling aluminum coil components after handling copper line sets or other tubing without first cleaning hands.

Unit Sizing

Unit size should be based on an acceptable heat loss or gain calculation for the structure, using methods like ACCA – Manual J. Ensure the air handler is connected to a duct system with an external static pressure within the allowable range and that airflow is within the minimum and maximum limits approved for the specific application.

Entering Air Temperature Limits

When supply ducts carry air to areas outside the containing space, return air must also be ducted and sealed to the air handler casing. Refer to the unit rating plate for model number and supply air plenum dimensions. The installer must check available supply power and verify it is within the unit's acceptable voltage range (208V-230V-1-60: 187V-253V).

Clearances

Maintain recommended clearances for refrigerant piping (12"), maintenance and servicing (36" from front), condensate drain lines, and filter removal (36"). Duct work connected to the unit is designed for zero clearance to combustible materials. A combustible floor base accessory is available for downflow applications.

Location

Choose a location with adequate structural support, service access, and clearance for duct connections. Wall mounting with hanging brackets is not recommended. Consider normal operating sound levels, which may be objectionable if the unit is placed directly over rooms. Ensure condensate lines can be routed to an open drain or outdoors, allowing for proper drainage. If the unit is installed in an attic or above a finished ceiling, an auxiliary drain pan is required by most local building codes. Ensure proper electrical supply is available. On installations in areas of high humidity, consider sealing unit openings and using fiberglass insulation with a vapor barrier to prevent nuisance sweating.

Air Handler Configuration

These units are supplied ready for upflow or horizontal left installation. For downflow or horizontal right configurations, the coil assembly must be repositioned. Refer to the specific conversion procedures.

NOTICE: For horizontal left applications with high airflow, the condensate pan must be angled properly to ensure drainage. Refer to Figure 5 for horizontal pan adjustment strap hole reference and Table 2 for strap settings.

Section IV: Duct Work and Connections

Air supply and return can be handled in various ways for upflow, horizontal, or downflow applications. Proper duct system design and installation are crucial for successful system operation. Use acoustical duct liner where noise is a concern and flexible duct connectors to minimize vibration. Ensure return air does not introduce hazardous substances into the airflow.

CAUTION: Use 1/2" screws to connect duct work to the unit. Longer screws can pierce the drain pan. If pilot holes are drilled, drill only through the field duct and unit flange.

Duct work not matching the supply air opening can cause turbulence, affecting airflow patterns and electric heater limit switches. If a factory-suggested transition cannot be fabricated, a block-off plate is recommended. All ducts should be suspended using flexible hangers.

CAUTION: This unit is not designed for non-ducted (freeblow) applications. Always operate the unit with filters installed.

Duct work should be fabricated and installed according to local and national codes, including NFPA No. 90B. If electric heat is used, non-flammable material must be used. Duct systems should be designed per ACCA Manual D.

Horizontal Suspension

For horizontal applications, use angle steel support brackets with threaded rods. Ensure sufficient clearance for access door removal.

Unit Connections

Supply and return air duct connections depend on the installation situation. Use a transition to match the unit opening. Refer to Table 1 for unit inlet and outlet dimensions.

CAUTION: Use 1/2" screws to connect duct work to the unit. Longer screws can pierce the drain pan and cause leakage. If pilot holes are drilled, drill only through field duct and unit bottom duct flange.

Duct work not designed to match the supply air opening can cause turbulence, affecting airflow patterns across electric heater limit switches. A block-off plate may be necessary. Ensure proper air circulation across limit switches.

Air Filters

CAUTION: Equipment should never be operated without filters.

Return air filters are required and must be field supplied. Filter access is available through an integral filter rack. Standard 1" filters are recommended, with options for permanent washable filters (model numbers: 1PF0601, 602, or 603). Refer to Table 3 for filter size.

Section V: Coil Metering Devices

A piston or TXV is to be installed in the field. Consult the outdoor unit's technical guide for the required piston or TXV. The Schrader core is supplied with the outdoor unit. If a piston is used, the Schrader core is installed in the suction line equalizer connection port. If a TXV is installed, the TXV equalizer line attaches to the equalizer connection port.

CAUTION: COIL UNDER PRESSURE. Verify pressure release by depressing the Schrader valve core.

The coil requires a metering device. See outdoor unit documentation for correct TXV or piston selection.

NOTICE: To prevent moisture and contaminants, temporarily close or plug coil openings if brazing cannot be completed during installation. Use masking tape for short delays and plugs or caps for longer delays. Do not purge the coil if this procedure is followed.

Piston Installation

WARNING: Failure to install the Schrader Valve Core in the vapor line equalizer connection port for piston applications could result in total refrigerant loss.

Follow these steps for piston installation: 1. Remove black plastic cap from equalizer connection port. 2. Adjust distributor position for proper alignment. 3. Install Schrader valve core. 4. Remove liquid line connection nut and sealing disc. 5. Slide nut over liquid line and discard seal disc. 6. Install piston into distributor per supplied data. 7. Verify Teflon washer is in place. 8. Install liquid line to distributor assembly and tighten. 9. Replace black plastic cap on unused equalizer fitting. 10. Leak test the system.

Thermostatic Expansion Valve (TXV) Installation

CAUTION: Outdoor units ending in "H" have a factory-installed hard start kit required for TXV installation. Outdoor units without "H" may not require it unless local regulations dictate.

Follow these basic steps for TXV installation, referring to the accompanying TXV kit instructions for detailed guidance. IMPORTANT: Refer to the Technical Guide to determine the proper TXV kit.

1. Relieve holding charge by depressing Schrader core. 2. Remove Schrader core. 3. Loosen and remove the distributor brass nut. 4. Install the TXV to the distributor assembly with supplied fittings. Hand tighten and turn an additional 1/4 turn to seal. CAUTION: Do not over-torque or use slip joint pliers. 5. Slide nut over liquid line, place Teflon washer on TXV, and install liquid line to the TXV. Hand tighten and apply an additional 1/4 turn to seal. 6. Install TXV equalizer line onto the vapor line by hand tightening the 1/4" SAE coupling nut and applying an additional 1/3 turn to seal. CAUTION: In all cases, mount the TXV temperature sensing bulb after the vapor line is brazed and cooled. Failure to use the suction line split grommet may result in TXV failure. 7. Pass the temperature sensing bulb tube through the access panel opening. 8. Install the TXV bulb to the vapor line near the cabinet using the bulb clamp(s). Ensure maximum contact. Mount the bulb at a 10 or 2 o'clock position on a horizontal run. If on a vertical run, position the bulb 8 inches away from the coil elbow with the tail end up. Insulate the bulb using provided thermal insulation.

Section VI: Refrigerant Line Connection

CAUTION: Coil is under inert gas pressure. Relieve pressure by depressing the Schrader core at the end of the suction manifold stub out.

CAUTION: Dry nitrogen should always be supplied through the tubing while brazing to prevent oxidation. Continue nitrogen flow until the joint has cooled. Use a pressure regulator and safety valve. A small flow is necessary to displace air and prevent oxidation.

NOTICE: Avoid handling aluminum coil components after handling copper line sets or other tubing without first cleaning hands.

Connect lines as follows: 1. Suction and liquid line connections are made outside the cabinet. Leave the tubing connection panel attached. Remove the coil access panel for brazing. Lines are expanded to receive field line set tubes. 2. Remove grommets where tubes exit the cabinet to prevent burning during brazing. 3. Cut the end of the suction tube using a tube cutter. Deburr the stub out. 4. If the coil does not have a factory-installed TXV, install the required piston or TXV kit. 5. If the coil has a factory-installed TXV, remove the soft-soldered liquid line copper cap. 6. Insert liquid and suction lines into the coil connections. 7. Wrap a water-soaked rag around the coil connection tubes inside the cabinet to avoid transferring excess heat. 8. Purge refrigerant lines with dry nitrogen.

NOTICE: All indoor coil connections are copper-to-copper and should be brazed with a phosphorous-copper alloy material. DO NOT use soft solder.

9. Braze the suction and liquid lines and allow joints to cool. 10. Route the TXV sensing bulb through the suction line opening. 11. Secure sensing bulb and equalizer line capillary tubes with nylon cable ties. 12. If a piston is used, install Schrader core into suction header and reinstall cap. 13. Re-attach grommets carefully to prevent air leakage. 14. Attach the coil access panel. 15. Refer to the Outdoor unit Installation Manual for evacuation, leak check, and charging instructions. Check all field brazed joints and metering device connections. 16. Ensure lines are sound isolated using appropriate hangers or strapping.

Section VII: Condensate Drain Connections

Drain lines should be trapped a minimum of three inches, pitched away from the unit drain pan, and be no smaller than the coil drain connection. Use 3/4" PVC or steel threaded pipe. Schedule 40 pipe is not necessary as drains are not subject to pressure.

CAUTION: Do not use Teflon™ tape, pipe thread compound, or other sealants, as this may cause damage and premature failure of the drain pan. Threaded drain connections should be hand-tightened, plus no more than 1 turn. Avoid double trapping of a single drain line.

Route the drain line to avoid interfering with accessibility to the coil, air handling system, or filter. Do not expose to freezing temperatures. See Figures 20 & 21 for drain connection locations.

CAUTION: When the unit is installed in an attic or above a finished ceiling, an auxiliary drain pan should be provided under the coil as specified by most local building codes. This exterior secondary drain pan should be piped to a location that will give the occupant a visual warning that the primary drain is clogged. If a secondary drain is not used, it must be plugged. Inspect and clean the evaporator coil drain pan regularly.

Section VIII: Electric Heater Installation

If the air handler requires electric heat, install the electric heat kit according to the included instructions. Mark the air handler nameplate to designate the installed heater kit. Use only 6HK Revision C or later heater kits. Refer to Tables 5-11 for information on required minimum motor speed taps and maximum over-current protection devices.

For upflow, downflow, and horizontal left applications, kits can be installed without modification. Field modification is required for horizontal right-hand airflow applications.

NOTICE: In some horizontal applications, service disconnects on electric heat kits must be rotated 180° so the up position is ON. This is required by UL1995, Article 26.19.

Section IX: Line Power Connections

Power can be brought into the unit through the supply air end or the left side panel. Use the appropriate hole for the unit's orientation. Terminate the power lead conduit at the electrical control box. Refer to Tables 7-11 and the National Electric Code for proper wire sizing. Seal wiring entry points to minimize air leakage.

All electrical connections must be made with copper conductors. Direct connection of aluminum wiring is not approved. If aluminum conductors are present, convert from aluminum to copper according to applicable codes. Conductor and connection ratings must meet or exceed the overcurrent protector's rating. Ensure existing aluminum wire is sized correctly for the application.

1 PHASE ELECTRIC HEAT OPTIONS: Single Source Power, Multi-Source Power with Jumper Bar.

3 PHASE ELECTRIC HEAT POWER OPTIONS: Single Source Power, Multi-Source Power.

Section X: Low Voltage Control Connections

The 24-volt power supply is provided by an internally wired low voltage transformer. If the unit is connected to a 208-volt power supply, the transformer must be rewired to the 208-volt tap. Field-supplied low voltage wiring can exit the unit through the top right or right side panel. Use a small hole with a 7/8" plastic bushing to minimize air leakage. Seal the wiring entry point. Field wiring connects to pigtails supplied with the air handler. Refer to Figures 22 & 25 for system wiring.

NOTICE: All wiring must comply with local and national electrical code requirements. Read and heed all unit caution labels.

Section XI: Blower Speed Connections

Adjust blower motor speed to provide airflow within the minimum and maximum limits approved for indoor coil, electric heat, and outdoor unit. Make speed tap adjustments at the motor terminal block. Connect motor wires to the desired speed tap receptacle.

The standard ECM motor operates on a 24 VAC signal to any of its 5-speed taps. If simultaneous inputs are present, the motor operates at the highest energized speed tap. The unit is factory wired with the electric heat kit connected to tap 5 for heating speed, and cooling/heat pump connected to tap 4. The thermostat's "G" signal provides the cooling/heat pump indicating speed. For fan-only operation, connect the factory "red" wire to the desired speed tap. Field install a wire from low voltage "YEL" to the desired speed tap for cooling/heat pump heating fan speed.

Section XII: Unit Data

Tables provide physical, electrical, and airflow data for the various models. This includes dimensions, motor specifications, voltage, amperage, filter size, and airflow data (CFM) at different external static pressures and blower speeds.

Section XIII: Maintenance

Filters must be cleaned or replaced when dirty. Inspect monthly. Cleaning frequency depends on operating hours and local conditions. Clean filters maintain unit efficiency.

Coil Cleaning

CAUTION: Ensure adequate precautions are taken to protect electrical components from liquid.

Clean coils with water. EVAP-Green by Nu-Calgon is an approved pH-neutral coil cleaner. Thoroughly rinse cleaned coils after use.

Lubrication

Blower motor bearings are permanently lubricated.

Condensate Drains

Check condensate drain lines seasonally to ensure proper flow from the primary drain and no flow from the secondary drain. If condensate flows from the secondary drain, shut off the unit and clean the condensate pan and drains.

Section XIV: Air System Adjustment

To check Cubic Feet per Minute (CFM), measure external duct static using a manometer and static pressure tips. Prepare the coil for static pressure measurements by running the fan only to ensure a dry coil. Refer to Table 12 for airflow data.

Drill two holes, 12" from the air handler in the supply air duct and 12" from the air handler in the return air duct (before any elbows). Insert pressure tips and energize the blower motor. Refer to Table 10 for airflow data and make necessary adjustments to keep CFM within coil airflow limitations.

External Duct Static

Measure supply air static pressure (positive) and return air static pressure (negative). Add the absolute values to determine total external system static pressure. If a filter rack is installed, measure return air duct static between the filter and the indoor coil.

Section XV: Installation Verification

Verify all installation tasks are accomplished as indicated in this installation manual prior to and during installation procedures.

Section XVI: Wiring Diagram

Refer to the wiring diagrams for proper low voltage field wiring connections when installing heater kits. Ensure the blower speed is set according to the air handler/heater kit combination specified in the installation instructions.

Section XVII: Typical Thermostat Connections

Diagrams illustrate typical thermostat wiring for various configurations, including cooling only, cooling with electric heat (10 kW and below, and 13 kW and above), and single-stage heat pump with electric heat.

Section XVIII: Start Up Sheet

This section provides a start-up sheet for the residential air handler with electric heat. It includes fields for owner information, equipment data, unit location and connections, electrical connections and inspection, air flow setup, and unit operation and cycle tests. It also covers owner education and comments on the job details.