LENNOX Packaged Rooftop Units Instruction Manual

LENNOX Packaged Rooftop Units

Specifications

• Product Name: Low Ambient Kit
• Model Number: 23V25; 619589-09
• Compatibility: KGC/KCC240 Packaged Rooftop Units
• Supersedes: 10/2023

Product Usage Instructions

Installation

1. Disconnect all power to the unit and open access panels.
2. Install the head pressure control (A190) in the designated control location.
3. Mount the temperature switch bracket onto the mullion and secure it with the provided screw.
4. Attach the temperature switch to the bracket.
5. Using the ICM Omni App, configure the head pressure controller settings as follows:
   • Probe Type: Pressure
   • Setpoint: 355 psig
   • Hard Start: 0.1s
   • Minimum Voltage Output: 32%
6. Install the pressure transducer on compressor 2 liquid line pressure tap.

Temperature Switch Wire Connections

1. Route temperature switch wires through the division panel between the compressor and outdoor coil sections.
2. Disconnect male and female terminals from wires marked S201 near the K10 relay.
3. Make wiring connections as shown in the provided diagram.

Low Voltage Wire Connections

Use the pressure transducer provided in the kit to make wire connections as per the provided diagram.

High Voltage Wire Connections

1. Disconnect factory wires from K254 terminals 4 & 6.
2. Reconnect these wires to the kit harness following the provided diagram.

Frequently Asked Questions

Q: Is it necessary to use gloves and protective clothing while handling the equipment?

A: Yes, it is recommended to wear gloves and protective clothing to prevent injuries from sharp sheet metal edges.

Q: Who should perform the installation and service of the low ambient kit?

A: Installation and service must be carried out by a licensed professional installer, service agency, or gas supplier to prevent property damage or personal injury.

Shipping and Packing List

Package 1 of 1 contains:

• 1- Head pressure control (A190)
• 1- Temperature switch bracket
• 1- Wiring harness – A190 to K254
• 1- Bag assembly containing:
  • 1- Pressure transducer (A188)
• 1-Temperature switch (S201) 10-Wire ties
• 1- Wiring diagram
• 2- Screws, #8-32 X 1/2 TFS
• 2-Screws, #8-32 X 1-1/4 TFS

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.

Application

This kit allows low ambient operation to 0°F (-17.8°C) unless otherwise noted in product specifications.

Operation

• When ambient temperature drops below 55°F (adjustable), the S201 temperature switch opens to de-energize the K10 relay coil. Condenser fans 1 & 3 are de-energized.
• Liquid line pressure transducer A188 converts the pressure to an analog signal which is sent to the head pressure control (A190).
• The head pressure control provides a variable output that slows Condenser Fan 2 & 4 operation at lower ambient temperatures.
• 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 installer (or equivalent), service agency, or gas supplier.

Installation

1. Disconnect all power to the unit and open access panels.
2. Install the head pressure control (A190) in the control
3. Install the temperature switch mounting bracket onto the mullion. Align the bracket with the 4th screw from the top of the unit; secure it with the provided screw. See FIGURE 1.
4. Install the temperature switch on the bracket.
5. Using the ICM Omni App, set the head pressure controller as follows:
   • Probe Type: Pressure Setpoint 355 psig
   • Hard Start: 0.1s
   • Minimum Voltage Output: 32%
6. Install the pressure transducer on compressor 2. Liquid line pressure tap as shown in FIGURE 2.

WARNING To prevent serious injury or death:

1. Lock-out/tag-out before performing maintenance.
2. If system power is required (e.g., smoke detector maintenance), disable power to the blower, remove the fan belt where applicable, and ensure all controllers and thermostats are set to the “OFF” position before performing maintenance.
3. Always keep hands, hair, clothing, jewelry, tools, etc., away from moving parts.

Temperature Switch Wire Connections

1. Route temperature switch wires through the division panel between the compressor and outdoor coil sections. See FIGURE 2.
2. Disconnect male and female terminals from wires marked “S201” near the K10 relay. See FIGURE 3.
3. Make wiring connections as shown in FIGURE 4.

Low Voltage Wire Connections

Use the pressure transducer, provided in this kit, to make wire connections as shown in FIGURE 5.

High Voltage Wire Connections

1. Disconnect factory wires to K254 terminals 4 & 6. Reconnect these wires to the kit harness as shown in FIGURE 6.
2. Connect the harness wire labeled “A190-L1” to the 120 – 600 VAC terminal.
3. Make the rest of the K254 harness connections as shown in FIGURE 6. Refer to the diagram in FIGURE 7.
4. Make sure all connections are secure.
5. Bundle wiring and use wire ties to route wiring away from sharp edges.
6. Place the wiring diagram provided in this kit on the inside of the control door.
7. Close unit panels and restore power.

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