LENNOX 507914-03 Low Ambient Kit Instruction Manual

July 2, 2024
Lennox

LENNOX 507914-03 Low Ambient Kit

Shipping and Packing List

Package 1 of 1 contains

  • 1- Head pressure control (A190)
  • 1- Temperature switch bracket
  • 1- Wiring harness – A190 24V power
  • 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 & 2 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 3 operation at lower ambient temperatures (A190 terminal M to B21 terminal 3).

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 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. Set the heat pump jumper to “CONTROL INPUT”.
  7. 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.LENNOX-507914-03-Low-Ambient-Kit-FIG-1 LENNOX-507914-03-Low-Ambient-Kit-FIG-2LENNOX-507914-03-Low-Ambient-Kit-FIG-3

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 24V harness, provided in this kit, to make transducer 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. Check the voltage to the unit. Connect the harness wire labeled “A190-L1” to the Line 1 / Motor 1 120 – 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.LENNOX-507914-03-Low-Ambient-Kit-FIG-5LENNOX-507914-03-Low-Ambient-Kit-FIG-6LENNOX-507914-03-Low-Ambient-Kit-FIG-7LENNOX-507914-03-Low-Ambient-Kit-FIG-9 LENNOX-507914-03-Low-Ambient-Kit-FIG-10
  • WARNING-ELECTRIC SHOCK HAZARD CAN CAUSE INJURY OR DEATH. UNIT MUST BE GROUNDED UNDER NATIONAL AND LOCAL CODES
  • FOR USE WITH COPPER CONDUCTORS ONLY
  • DISCONNECT ALL POWER BEFORE SERVICING
  • IF ANY WIRE IN THIS APPLIANCE IS REPLACED, IT MUST BE REPLACED
  • WITH WIRE OF LIKE SIZE, RATING, INSULATION THICKNESS AND TERMINATION
  • REFER TO THE UNIT RATING PLATE FOR THE MINIMUM
  • CIRCUIT AMPACITY AND MAXIMUM OVERCURRENT PROTECTION
  • F10 IS USED ON Y-VOLT UNITS ONLY
  • REFER TO INSTRUCTION SHEETS FOR LOW
  • AMBIENT HARNESS INSTALLATION PROCEDURE

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