Lennox Outdoor Control Replacement Kit Installation Instructions

Shipping and Packing List

Check kit for shipping damage. Consult the last carrier immediately if damage is found.

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.

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.

WARNING: Electric Shock Hazard! Disconnect all power supplies before servicing. Replace all parts and panels before operating. Failure to do so can result in death or electrical shock.

General

This instruction covers the removal and replacement of the iComfort unit control board, the removal of the PWM fan control and the installation of the new compressor solenoid harnesses for older two-stage units.

This kit can be field-applied to models that use a single- or two-stage outdoor control listed in Table 1.

TABLE 1. iComfort Existing Outdoor Controls and Components

NOTE: This kit can be used in the following models:

• All versions of the XC17, XP17, XP17N, XP21, XP21N, SL18XC1 and SL18XP1.
• XP19-XX-230-06 only.
• XC21-XX-230-04 or higher.

IMPORTANT: TWO-STAGE (XP19-XX-230-06 AND XP21) OUTDOOR HEAT PUMP UNITS BUILT BEFORE FEBRUARY 2012: THESE SYSTEMS WILL REQUIRE A 70VA CONTROL TRANSFORMER (CATALOG # 13H2801 ORDER SEPARATELY) FOR INDOOR AIR HANDLERS THAT USE ECB29 ELECTRIC HEAT SECTIONS LARGER THAN 10 KW. THE LARGER 70VA IS REQUIRED TO HANDLE THE REVISED LOADING OF THE TWO-STAGE SOLENOID IN THE COMPRESSOR.

Control Replacement

1. Disconnect all power to system (indoor and outdoor units).
2. Remove the existing communicating thermostat from the wall base.
3. Remove unit access panel. See unit installation instructions for access panel removal procedure.
4. Tag location of wires attached to the existing control. Use wiring diagram on access panel for reference if necessary. The replacement control may be configured differently, so it is essential that the wires be clearly marked with the current terminal connection.
5. Remove all wiring connections from installed control.
6. Remove existing outdoor control.
7. Install new outdoor control in the same location as original outdoor control.
8. Reconnect wires to same terminals as original outdoor control. NOTE: Terminals may not be in the same location on the replacement control.
9. Turn the main power on to the indoor unit and outdoor unit. Control should auto program the settings and the outdoor unit model number and serial number will be transferred into the new control. On systems installed with the iComfort Wi-Fi thermostat, the thermostat will display "Compatible Device Found”. Select “Yes” to copy the model and serial number into the new control. If it does not, turn off power to system and remove i+ and i- communicating wires, leaving R and C wires connected. Turn power back on and use push button on control to program control using procedure outlined in figures 2, 3 and 4.
10. Turn indoor and outdoor power off and reconnect the i+ and i- wires to the control board.
11. Turn main power ON to indoor and outdoor unit.
12. Reinstall unit panels and verify unit operation.

WARNING: ELECTROSTATIC DISCHARGE (ESD) Precautions and Procedures: Electrostatic discharge can affect electronic components. Take care during unit installation and service to protect the unit's electronic controls. Precautions will help to avoid control exposure to electrostatic discharge by putting the unit, the control and the technician at the same electrostatic potential. Touch hand and all tools on an unpainted unit surface before performing any service procedure to neutralize electrostatic charge.

Configuring Unit - Single Stage

For the new outdoor control to work correctly, it MUST BE programmed for unit type (AC or HP and number of stages), unit capacity and outdoor fan profile (RPM). The new outdoor control has an auto-detection feature that will determine the unit type. The following set up procedures MUST be done on all new outdoor controls.

Auto-Detection of Unit Type (air conditioner or heat pump and number of stages)

During initial power-up the control will auto-detect the unit type. The unit type is determined by what is connected to various outputs on the new control.

The unit capacity and fan speed are manually configured. Until those parameters are configured the 7-segment display will show 3 bars for the unit capacity and fan speed.

Key Configuration Points:

• Anytime there is a connection to REV terminal, the control will detect the unit type as a heat pump.
• Anytime there is no connection to REV terminal, the control will detect the unit type as an air conditioner.
• Anytime there is a connection to Y2 S terminal, the control will detect the unit as two-stage.
• Anytime there is no connection to Y2 S terminal, the control will detect the unit as single-stage.

If the control auto-detects the unit type incorrectly, it may be due to the control being miswired, loose connection, or missing connection to the required control output terminal. Disconnect power to the control, verify connections, correct wiring, and reconnect power. Verify that the correct unit type is displayed on the seven-segment display.

Configuring Unit Type

During initial power-up the control will auto-detect the unit type. The unit type is automatically determined by what is connected to Y2 S and/or REV on the control. The unit type can be permanently stored in the control's memory by manually configuring the unit type using the following procedure. Typically, the capacity and fan speed will not be configured and will display the three dashes for each. For manual configuration of the unit type, proceed as indicated.

Procedure:

• To enter unit type configuration, push and hold the button next to the single character display until the dash symbol appears and immediately release the button. Once the dash starts blinking, proceed to the next step.
• Push and hold the button until the 'Pt' sequence is displayed on the seven-segment display and then immediately release the button. This configuration sequence allows the installer to select a unit type (number/letter combination) that matches the outdoor unit type and number of stages.
• Press and hold the button during the 'Pt' cycling display. The 'Pt' sequence will repeat 5 times, and if a selection is not made, the control will return to idle mode.
• Selection Process:
• 1. When the correct unit type is displayed, release the button immediately. The display will start flashing.
• 2. Push and hold the button until selection stops flashing during one of the three cycles. Release the button.
• 3. If a selection is not made during those three cycles, the control will return to idle mode.

If three horizontal bars display in any part of the 7-segment string during power up, the outdoor control did not store that configuration (unit type, capacity, or fan profile). If this happens, the configuration sequence for that section of the string must be repeated.

During power up of the outdoor control, the seven-segment display will show the stored number of stages, unit type, capacity, and outdoor fan speed (e.g., 2HP PAUSE 36 PAUSE 12).

Configuring Unit Capacity or Fan Profile

Power-up: Unit capacity (two-digit number) and displayed represents unit size code (outdoor unit capacity). During initial power up, the number of stages / unit type, unit capacity, and outdoor fan speed will appear on the 7-segment display.

If three horizontal bars display in any part of the 7-segment display string sections during power-up, the outdoor control did not store that configuration (unit type, capacity, or fan RPM). If this happens, the configuration sequence for that section of the string must be repeated.

Procedure:

• To enter unit capacity or fan profile configuration, push and hold the button next to the single character display until the dash symbol appears and immediately release the button. Once the dash starts blinking, proceed to the next step.
• Push and hold the button until the 'PC' or 'PF' sequence is displayed on the seven-segment display and then immediately release the button. This configuration sequence allows the installer to select a unit type (number/letter combination) that matches the outdoor unit type and number of stages.
• Press and hold the button during the 'PC' or 'PF' cycling display. Either the 'PC' or 'PF' sequence will repeat 5 times, and if a selection is not made, the control will return to idle mode.
• Selection Process:
• 1. When the correct unit capacity or fan profile is displayed, release the button immediately. The display will start flashing.
• 2. Push and hold the button until selection stops flashing during one of the three cycles. Release the push button.
• 3. If a selection is not made during those three cycles, the control will return to idle mode.

NOTE: Units with PWM controlled fan motors - The fan motor profile must be field set or three bars will appear in the fan profile string section of the 7-segment display. The factory default is 700 RPM.

If three horizontal bars display in any part of the 7-segment display string during power-up, the outdoor control did not store that configuration (unit type, capacity, or fan profile). If this occurs, the configuration sequence for that section of the string must be repeated.

During power up of the outdoor control, the seven-segment display will show the stored number of stages, unit type, capacity, and outdoor fan speed (e.g., 2HP PAUSE 36 PAUSE 2).

TABLE 2. Fan Profile Codes

Air Conditioner or Heat Pump Control Removal

1. Disconnect power to the indoor and outdoor units at both service disconnect switches.
2. Remove unit access panel. See unit installation instruction for access panel removal procedure.
3. Remove the necessary wiring attached to the existing control (A175) and PWM fan control (A177) (if present) in order to remove them.

NOTE: Remove the existing 2-stage compressor solenoid harness as noted below and discard.

TABLE 3. Record Low-Voltage Field Wiring

XP19-XX-230-06 Units Only

1. Disconnect power to the indoor and outdoor units at both service disconnect switches.
2. Remove unit access panel. See unit installation instruction for access panel removal procedure.
3. Remove the necessary wiring attached to the existing control (A175).

NOTE: REMOVE AND DISCARD 2-STAGE SOLENOID PLUG HARNESS ON UNITS USING 101796-XX OUTDOOR CONTROL.

TABLE 4. Record Low-Voltage Field Wiring

XC21-XX-230-04 Units Only

1. Disconnect power to the indoor and outdoor units at both service disconnect switches.
2. Remove unit access panel. See unit installation instruction for access panel removal procedure.
3. Remove the necessary wiring attached to the existing control (A175).

NOTE: REMOVE AND DISCARD 2-STAGE SOLENOID PLUG HARNESS ON UNITS USING 101798-XX OUTDOOR CONTROL.

TABLE 5. Record Low-Voltage Field Wiring

XC21-XXX-230-04 – Electronically Commutated Motor (ECM) Fan Motor (Typical Original Wiring)

1. Remove existing outdoor control (A175) and PWM fan control (A177) from panel.

NOTE: Unused holes are only present if 101796-XX, 101797-XX, 101798-XX or 101799-XX outdoor control is being replaced.

Air Conditioner or Heat Pump Control Installation

1. Install new outdoor control (A175) and wire per wiring diagram below.

NOTE: Install the new two-stage compressor solenoid harness as noted below.

NOTES:

• 1. Use the information entered in table 2 to make the connections for the low-voltage field wiring.
• 2. The new outdoor control (A175) does not include an integrated LSOM function. A ComfortAlert Ultratech Diagnostics module will need to be purchased separately (catalog number 85M53) if that feature is desired. The new outdoor control's R, C and L terminals are used to connect this device.

XC17 and XP17 Interlink Compressor Used (Control Replacement Only)

1. Install new outdoor control (A175) and wire per wiring diagram below.

NOTES -

• 1. Use the information entered in table 2 to make the connections for the low-voltage field wiring.
• 2. Compressor thermal switch is present on XC17 and XP17 when an Interlink compressor is used. Units are equipped with a compressor-mounted normally-closed temperature switch that prevents compressor damage due to overheating caused by internal friction. The switch is located on top of the compressor casing. This switch senses the compressor casing temperature and opens at 239-257°F (115°C-125°C) to shut off compressor operation. The auto-reset switch closes when the compressor casing temperature falls to 151-187°F (66°C-86°C), and the compressor is re-energized. This single-pole, single-throw (SPST) bi-metallic switch is wired in series with the high pressure switch.