This article provides a detailed overview of the installation and maintenance procedures for Advanced Distributor Products (ADP) evaporator coils, based on official technical documentation. The instructions are tailored for HVAC professionals and technical users in the U.S. who are responsible for the proper setup of heating, ventilation, and air conditioning systems. The guidelines cover installation, refrigerant line setup, metering device configuration, condensate drainage, and compliance with safety and environmental regulations.
Installation Overview
ADP evaporator coils are designed to be used with condensing units or heat pump systems. These coils are available for refrigerants such as R-22 and R-410A and are compatible with or without a thermostatic expansion valve (TXV). Installation should follow the general guidelines provided by ADP to ensure proper system performance and safety.
Prior to installation, the coil must be inspected for any shipping damage. If damage is found, it should be reported immediately to the carrier. The coil is shipped with a 10 psi dry air holding charge, and a puncture rubber plug must be removed from the suction line to release the charge before installation. It is important to note that the absence of pressure does not necessarily confirm the system is leak-free. A leak check should be performed before installation or prior to returning the coil to the supplier.
Local codes and manufacturer specifications must be consulted before beginning installation. For example, coil efficiency metrics such as SEER, EER, and HSPF must be compatible with the matched condensing or heat pump unit. The AHRI directory can be referenced to ensure proper compatibility.
Metering Device Installation and Configuration
When changing the metering device, it is crucial that the new device is compatible with the refrigerant type and capacity of the condensing unit. Failure to match these specifications can lead to poor system performance and potential damage to the compressor. ADP recommends that all coils be matched according to the AHRI directory.
For systems with a non-bleed TXV and a reciprocating compressor, a hard start mechanism is required on the outdoor unit. When switching between an AC system and a heat pump system, the existing TXV specifications must be reviewed to determine whether a replacement is necessary.
When installing or reattaching a TXV sensing bulb, ADP recommends positioning it at a 10 to 2 o’clock position on the suction line, no more than one foot from the connection. The bulb should be placed outside the coil housing and insulated properly. It is also important to reattach the bulb after brazing to avoid overheating, as a wet rag should be placed around the suction line at the cabinet during brazing to prevent heat transfer to the bulb.
If the bulb is installed on a vertical suction line, it must be placed before any trap, with the capillary tube facing upward. This ensures accurate sensing of the refrigerant flow and prevents operational issues.
Refrigerant Line Installation and Charging
ADP provides specific guidance for refrigerant line installation. It is recommended to install a filter drier and sight glass in the liquid line to prevent contamination during brazing. Nitrogen should be used to purge the system during brazing to maintain system integrity.
The system should be evacuated to 500 microns to remove air and moisture. ADP recommends using a deep evacuation or triple evacuation method for optimal results. After evacuation, the suction service valve should be opened slowly to allow refrigerant to bleed into the system before opening the liquid service valve.
For refrigerant charging, ADP specifies that the outdoor temperature should be at least 60°F when charging in cooling mode. Between adjustments, the system should be allowed to run for at least 15 minutes to stabilize pressures. For systems with micro-channel outdoor coils, small charge adjustments (1 ounce or less) are recommended due to the sensitivity of these systems to refrigerant levels.
For TXV charging, the method recommended by the outdoor unit instructions should be followed. Alternatively, ADP suggests charging to 12°F sub-cooling for AC units and 10°F sub-cooling for heat pump units. If the system is equipped with an adjustable TXV, it should be adjusted to 10°F superheat for optimal performance.
In the event of any issues or questions regarding refrigerant charge, ADP advises contacting customer service for further assistance. It is also important to note that OEM charging methods can vary depending on design and application, so all recommended pressures, temperatures, sub-cooling, and superheat settings should be verified to ensure proper charging.
Condensate Drainage and Drain Pan Installation
Proper condensate drainage is essential for the safe and efficient operation of evaporator coils. The drain line should be routed in a way that avoids freezing temperatures and does not interfere with the accessibility of the coil, air handling system, or filter. The drain should be pitched downward at a rate of 1 per 10 feet, with a 2-trap installed as close to the coil as possible.
If the system includes an extended run or a second trap, a vent tee should be installed after the trap closest to the coil. Additionally, if the coil is installed in or above a living space where damage could occur from condensate overflow, a separate ¾-inch drain must be provided from the secondary drain connection. This drain should be routed to a location that is visible and in compliance with local installation codes.
Condensate flowing from the secondary drain typically indicates a clogged primary drain. To prevent this, the trap should be primed with water and the line tested for leaks. During system operation, the water flow should also be tested. A secondary drain pan should be installed under the unit as required by most local building codes.
ADP provides several drain pan configuration options, including routing the secondary drain to a noticeable area, into the secondary pan using a provided drain nipple, or connecting with a TEE to the secondary drain pan. These options are provided for guidance and do not override local code requirements.
Piston Installation and Replacement
For systems using a piston instead of a TXV, the piston must be sized according to the recommendation from the outdoor unit manufacturer. If the outdoor unit does not specify a piston size, ADP provides a piston size chart for reference.
When replacing ADP pistons, the following procedure should be followed:
- Loosen the hex nut located on the liquid line and separate it from the distributor assembly.
- Remove the existing piston from inside the distributor assembly.
- Insert the new piston into the distributor assembly.
- Inspect the Teflon O-ring and replace it if damaged. Ensure the O-ring is properly seated.
- Re-install the hex nut to the body and torque it to 10 ft-lbs.
It is important to ensure that all components are properly aligned and tightened to the specified torque to prevent refrigerant leaks and system inefficiencies.
Furnace and PLENUM Connections
When attaching the evaporator coil to a furnace, the bottom edges of the coil and furnace should be aligned. A furnace mount bracket, typically included with the coil, can be attached using two screws. The coil should then be secured to the furnace flanges using sheet metal screws, and all connections should be sealed according to local code requirements.
Support options for the coil include bottom support using furnace stands or hanging straps attached to the back end of the sheet metal. The coil should be level or slightly pitched toward the drain connections to ensure proper condensate flow.
For plenum connections, duct takeoff options should be selected based on the specific installation requirements and local codes. Proper ductwork configuration is essential for optimal airflow and system efficiency.
Safety and Environmental Considerations
ADP emphasizes the importance of following all safety guidelines during installation. Before beginning any work, the installation manual should be reviewed, and all warning statements should be heeded. Local authorities having jurisdiction should be consulted to ensure compliance with all applicable codes and regulations.
Environmental considerations are also a key concern. The Clean Air Act of 1990 prohibits the intentional venting of refrigerants, including CFCs and HFCs. Approved methods of refrigerant reclaiming must be followed, and violations can result in fines or legal consequences.
Warranty and Equipment Information
ADP offers a limited warranty for its evaporator coils. The warranty covers defects in material and workmanship for a period of five years from the date of installation or six years from the date of manufacture, whichever comes first. The warranty does not cover damage resulting from improper installation, misuse, or failure to follow manufacturer instructions.
To access warranty terms, register for an extended warranty, or file a warranty claim, users should visit www.ADPwarranty.com. In states or provinces where registration is not required, the absence of registration does not affect warranty rights.
Conclusion
ADP evaporator coil installation requires careful attention to detail, adherence to manufacturer specifications, and compliance with local codes. The proper setup of refrigerant lines, metering devices, and condensate drainage systems is essential for the safe and efficient operation of the HVAC system. By following the detailed guidelines provided in the installation manuals and technical documents, HVAC professionals can ensure that the system performs optimally and meets all regulatory requirements.