Lennox Ignition Control Replacement Kit
Installation Instructions for Ignition Control Conversion Kit 19W94
Used with 80MGF(X)-1/3 and 80MGF(X)/G24M(X)-2/4/6 Units
Document Reference: 505,178M, 02/06
Important Safety Information
WARNING: This conversion kit must be installed by a qualified Lennox service technician or other qualified agency. Failure to follow instructions precisely can result in fire, explosion, property damage, personal injury, or death. The qualified agency assumes responsibility for this conversion.
CAUTION: Electrostatic discharge (ESD) can affect electronic components. Take precautions to protect the furnace's electronic controls by neutralizing static charge. Touch an unpainted unit surface (like the gas valve or blower deck) with your hand and tools before performing any service.
Kit Contents and Application
Package 1 of 1 Contains:
- 1 - Replacement ignition control 100980-01 with adapter plate
- 1 - Ignition cable
- 1 - Wiring harness - 80MGF(X) -1/3 (P166 15-pin female plug with female pins)
- 1 - Wiring harness - 80MGF(X)/G24M(X)-2/4/6 (P166 15-pin female plug with male pins)
- 2 - Wire nuts - 80MGF(X) -1/3
- 4 - #8-18x1/2 self-drill self-tap screws
- 2 - Wiring schematic stickers
- 1 - Diagnostic sticker
- 4 - Unused hole stickers
- 1 - Unit conversion sticker
- 7 - Wires - 80MGF(X) -1/3 (02/06)
Note: This kit includes components for two different unit series. Use only the parts required for the specific unit being converted.
Shipping Damage: Inspect all components for shipping damage. Contact the carrier immediately if damage is found.
Application - 80MGF(X)-1/3: This kit converts 80MGF(X)-1/3 units from Ram control (3MC-4) 20J8001 to integrated control 100980-01.
Application - 80MGF(X)/G24M(X)-2/4/6: This kit converts 80MGF(X)/G24M(X)-2/4/6 units from Ram control (3MC5-01) 33J6201 to integrated control 100980-01.
Installation Instructions - 80MGF(X)-1/3
WARNING: Ensure ALL power to the unit is OFF before installation or servicing. Multiple disconnect switches may exist. Electrical shock can cause injury or death.
- Set thermostat to the lowest setting. Shut off gas supply and disconnect electrical power.
- Remove access door and turn gas valve knob to OFF.
Removal of Ram Control and Related Wiring (Refer to Figure 2)
- Disconnect the ignition cable from the ignitor and control board; discard.
- Cut the brown wire (from blower harness plug to terminal "H-OUT" of control board) near the control board.
- Disconnect all wires from the control board.
- Separate the main wire harness connection. Cut the brown wire (main plug terminal "5") near the main plug (on the blower harness plug side). Disconnect the white wire (main plug terminal "9") from the transformer. Discard the control board side of the main plug harness.
- Disconnect remaining wires from the transformer and discard.
- Remove and discard the existing control board.
Installation of Replacement Control and Related Wiring (Refer to Figure 3)
- Cover any unused blower access panel holes with the provided small blank stickers.
- Secure the new control board to the blower access panel using four provided screws, positioning it near the original control board location. Orient the board so the connection plug is in the top right corner (for upflow position).
- Connect the provided six wires as follows:
- Connect blue wire from 24V transformer side to "24VAC HOT" terminal.
- Connect yellow wire from 24V transformer side to "24VAC RTN" terminal.
- Connect green/yellow wire from transformer mounting screw to "GROUND" terminal.
- Connect black wire from "120V" transformer terminal to "120VAC TX" terminal.
- Connect one white wire (with a terminal on each end) from the transformer common terminal to "120VAC RTN" terminal.
- Connect the other white wire from the common 120V power supply to "120VAC RTN" terminal.
- Connect one side of the door switch to the "120VAC HOT" terminal on the control board. Connect the other side to the hot side of the 120V power supply.
- Connect the provided ignition cable to the control board and ignitor. IMPORTANT: Route the ignition lead separately; do not include it in any bundled wires.
- Select the correct adapter wire harness. The 15-pin "P166" female plug has female pins.
- Connect the male plug of the 80MGF(X)-1/3 adapter wire harness to the female plug on the control board.
- Connect the female plug of the 80MGF(X)-1/3 adapter wire harness to the male plug of the main unit wire harness.
- Connect the wire from pin "7" of the 80MGF(X)-1/3 adapter harness to the "120VAC RTN" terminal of the control board.
- Connect the wire from pin "9" of the 80MGF(X)-1/3 adapter harness to the "CMB BL WR" terminal of the control board.
- Using a wire nut, connect the brown wire from pin "5" of the 80MGF-1/3 adapter harness to one of the brown wires from the blower harness plug.
- Using a wire nut, connect the brown wire from pin "8" of the 80MGF-1/3 adapter harness to the other brown wire from the blower harness plug.
- Blower Speed and Continuous Fan Connections:
- For units with existing continuous low speed fan operation: Do not install the continuous fan jumper. Do not change the existing low speed tap connection. Make the ACB HEAT and ACB COOL connections as shown in Figure 3.
- For units with no continuous low speed fan operation: Connect the provided continuous fan jumper between the control board terminals ACB HEAT and ACB LOW to enable continuous fan operation on heating speed when the thermostat is set to FAN ON and there is no heating or cooling demand. Make the ACB HEAT and ACB COOL connections as shown in Figure 3.
- Remove the existing wiring diagram sticker from the unit access panel and replace it with the provided 535,330W sticker.
- Replace the existing diagnostic sticker on the blower access panel with the provided replacement sticker.
- Affix the provided unit conversion sticker next to the existing rating plate inside the cabinet.
Installation Instructions - 80MGF(X)/G24M(X)-2/4/6
WARNING: Ensure ALL power to the unit is OFF before installation or servicing. Multiple disconnect switches may exist. Electrical shock can cause injury or death.
- Set thermostat to the lowest setting. Shut off gas supply and disconnect electrical power.
- Remove access door and turn gas valve knob to OFF.
Removal of Ram Control and Related Wiring
- Disconnect the ignition cable from the ignitor and control board; discard.
- Mark and disconnect all wires from the control board.
- Separate the main wire harness connection at the control board plug.
- Remove and discard the existing control board.
Installation of Replacement Control and Related Wiring (Refer to Figure 4)
- Cover any unused blower access panel holes with the provided small blank stickers.
- Secure the new control board to the blower access panel using four provided screws, positioning it near the original control board location. Orient the board so the connection plug is in the top right corner (for upflow position).
- Reconnect existing wires as follows:
- On 80MGF(X)-2/4/6 units: Reconnect blue wire from 24V transformer side to "24VAC HOT" terminal.
- On G24M(X)-2/4/6 units: Reconnect blue wire from circuit breaker to "24VAC HOT" terminal.
- Reconnect yellow wire from 24V transformer side to "24VAC RTN" terminal.
- Reconnect green/yellow wire from transformer mounting screw to "GROUND" terminal.
- Reconnect black wire from "120V" transformer terminal to "120VAC TX" terminal.
- Reconnect the white wire from the common 120V power supply to "120VAC RTN" terminal.
- Connect one side of the door switch to the "120VAC HOT" terminal on the control board. Connect the other side to the hot side of the 120V power supply.
- Connect the provided ignition cable to the control board and ignitor. IMPORTANT: Route the ignition lead separately; do not include it in any bundled wires.
- Select the correct adapter wire harness. The 15-pin "P166" female plug has male pins for this model series.
- Connect the male plug of the 80MGF(X)/G24M(X)-2/4/6 adapter wire harness to the female plug on the control board.
- Connect the female plug of the 80MGF(X)/G24M(X)-2/4/6 adapter wire harness to the male plug of the main unit wire harness.
- Connect the wire from pin "2" of the 80MGF(X)/G24M(X)-2/4/6 adapter harness to the "120VAC RTN" terminal of the control board.
- Connect the wire from pin "1" of the 80MGF(X)/G24M(X)-2/4/6 adapter harness to the "CMB BL WR" terminal of the control board.
- Connect the blower heating speed tap to the "ACB HEAT" terminal, the low speed tap to "ACB LOW" terminal, and the cooling speed tap to "ACB COOL" terminal (refer to Figure 6 for speed tap).
- Remove the existing wiring diagram sticker from the unit access panel and replace it with the provided 535,329W sticker.
- Replace the existing diagnostic sticker on the blower access panel with the provided replacement sticker.
- Affix the provided unit conversion sticker next to the existing rating plate inside the cabinet.
Control Board Operation
The integrated control (100980-01) manages blower operation, fan off timings, thermostat connections, and ignition. It features two diagnostic LEDs and a memory recall button. Refer to the diagnostic codes section or sticker for LED interpretation and flow charts for operation sequences.
Blower Speed / Timing Adjustments
IMPORTANT: Turn electrical power OFF before making adjustments.
Continuous Speed: Systems with a cooling thermostat subbase may use the thermostat's Fan-ON switch for continuous blower operation. For systems without a cooling subbase, a toggle switch between "R" and "G" terminals is required. Refer to Figure 5 (80MGF(X)-1/3) or Figure 6 (80MGF(X)/G24M(X)-2/4/6) for factory-connected blower speed taps.
80MGF(X)-1/3 Units (See Figure 3): If a continuous low speed fan is already connected independently of the control board, do not connect the continuous fan jumper. If not, install the jumper as per step 13 of the 80MGF(X)-1/3 installation to achieve continuous fan operation on heating speed.
WARNING: Do not install the jumper if continuous low speed is already installed at the control board ACB terminal or via a separate circuit controlled by the thermostat's G terminal. This could damage the control board and/or blower motor.
80MGF(X)/G24M(X)-2/4/6 Units: The blower will operate continuously on low speed when connected as outlined in step 11 of the 80MGF(X)/G24M(X)-2/4/6 installation section.
Fan On and Off Timings
The fan on time is fixed at 45 seconds. The fan off time (blower operation after heating demand is met) is adjustable by moving a jumper on the integrated control board. The replacement control ships with a factory fan off setting of 180 seconds. Adjusting fan off time can enhance comfort and suit individual applications. Refer to Figure 1 for Fan-Off Time Adjustment.
Figure 1: Fan-Off Time Adjustment - To adjust fan-off timings, remove the jumper and select another pin combination for the desired time. Leave the jumper off for a 240-second fan-off timing.
Start-Up Procedure
Before lighting: Smell around the appliance area for gas, especially near the floor, as gas can be heavier than air.
Use only your hand to move the gas control knob. Never use tools. If the knob is stiff, do not attempt repair; call a qualified service technician. Force or attempted repair can cause fire or explosion.
- Ensure the thermostat is set below room temperature and unit power is OFF.
- The appliance has an automatic ignition device; do NOT attempt to light the pilot burner manually.
- Turn the gas valve knob to OFF. Do not force.
- Wait 15 minutes to clear out any gas. If gas is still detected, immediately call your gas supplier from a neighbor's phone and follow their instructions. If no gas is smelled, proceed.
- Turn the gas valve knob to ON.
- Turn on all electrical power to the unit.
- Set the thermostat to above room temperature.
- Check gas line supply pressure with the unit operating. Ensure the minimum pressure shown on the name rating plate is available. Check and adjust manifold pressure to the value indicated on the unit rating plate.
- Set the heat anticipator: 0.65 for Honeywell gas valves, 0.50 for White-Rodgers gas valves.
- Run the unit through at least three complete cycles to verify normal operation.
- Set the thermostat to the desired setting.
- Replace the access panel.
Wiring Diagrams
The document includes several wiring diagrams illustrating the connections for different models and conversion scenarios:
- Figure 2: Wiring Diagram for 80MGF(X)-1/3 Units Converted from RAM Control Board 3MC-4 (20J8001) to Integrated Control (100980-01). This diagram shows the original setup and the connections for the conversion, highlighting wires to be cut and specific component connections like the transformer, ignitor, RAM control board, main unit harness, and blower harness.
- Figure 3: Wiring Diagram for 80MGF(X)-1/3 Units with Integrated Control (100980-01). This diagram details the connections for the new integrated control board, including the adapter wire harness (P166 female to J20 male), main unit harness (J166 male), transformer, ignitor, blower motor, and continuous fan jumper. It specifies connections for blower speed taps (ACB HEAT, ACB LOW, ACB COOL).
- Figure 4: Wiring Diagram for 80MGF(X)/G24M(X)-2/4/6 Units with Integrated Control (100980-01). Similar to Figure 3, this diagram illustrates the wiring for the G24M series units, including the specific adapter wire harness (P166 female to J20 male with male pins), circuit breaker connections (not used on 80MGF(X)), and connections to the integrated control board, transformer, ignitor, and blower motor.
- Figure 5: A comprehensive wiring diagram for 80MGF(X)-1/3 units converted from RAM control to integrated control, showing the integrated control board, transformer, ignitor, blower motor, combustion air blower, various limit switches (secondary, primary, flame rollout, low pressure), door interlock switch, and their interconnections. It also includes a key for components, blower speed charts, and notes on continuous fan jumpers and wire replacement.
- Figure 6: A comprehensive wiring diagram for 80MGF(X)/G24M(X)-2/4/6 units converted from RAM control to integrated control, similar to Figure 5 but tailored for the G24M series, detailing circuit breaker usage and specific harness connections.
Blower Speed Charts
The document provides charts detailing factory-connected motor speed taps and blower speed selection for various unit models:
| UNIT | SPEED TAP | SPEEDS | ||||
|---|---|---|---|---|---|---|
| COOL | HEAT | CONT AVAILABLE | ||||
| 02-45/60 | 2 | 4 | 4 | |||
| 03-60/75 | 2 | 4 | 4 | |||
| 04-75, 3/4-100 | 2 | 4 | 5 | |||
| 04/5-100/120 | 2 | 5 | 5 | |||
| 02-75 | 2 | 3 | 4 | |||
| 04/5-140, 3/4-120 | 2 | 3 | 5 |
Blower Speed Selection
| SPEED | 2 | 3 | 4 | 5 | 4 | |
|---|---|---|---|---|---|---|
| TAP | 2 | 3 | 4 | 5 | 6 | 5 |
Important Note: To prevent motor burnout, never connect more than one motor lead to any single connection.
Refer to installation instructions for changing motor speed taps and blower speed selection procedures.
Diagnostic Codes
The integrated control board provides diagnostic information via LEDs. The following table outlines diagnostic patterns, their indications, and recommended remedies:
| DSI BOARD DIAGNOSTIC PATTERNS | MODE INDICATION | REMEDY |
|---|---|---|
| DIAG 1 Flashing Together DIAG 2 Flashing Together | Normal Operation | None. Slow flashing LED signifies normal operation. Fast flashing LED indicates a heating demand. |
| DIAG 1 Flashing DIAG 2 On | Limit Switch Open | This LED pattern indicates that either the primary or secondary limit switch has opened. Both switches are auto-reset. |
| DIAG 1 Off DIAG 2 Flashing | Pressure Switch Open | This LED pattern indicates that the pressure switch opened during operation due to reduced flow of combustion products or a blocked condensate drain. |
| DIAG 1 Flashing Alternately DIAG 2 Flashing Alternately | Watchguard | The system is in Watchguard mode. Burners have failed to ignite. |
| DIAG 1 Flashing DIAG 2 Off | Flame Failure | This LED pattern indicates that a flame was sensed without power to the gas valve. |
| DIAG 1 On DIAG 2 Flashing | Flame Roll-Out | This LED pattern indicates that the flame roll-out switch has opened. Check continuity of switch and for blockage in heat exchanger. Manually reset switch. |
| DIAG 1 Continuously On DIAG 2 Continuously On | Control Board Failure | Remove power to reset control. Run cycle. Check control wiring and replace the EGC-1 control board, if necessary. |
Sequences of Operation
The document outlines the operational sequences for heating, cooling, and manual fan modes:
Normal Heating Mode
Initiates with control main power ON. Checks for flame, control self-check, and roll-out switch closure. If conditions are met, the thermostat calls for heat, activating the LED to a fast flash rate. The combustion air blower starts, followed by a prepurge, then ignition trial. If flame is registered within 10 seconds, the main gas valve opens. If flame is sensed after the rectification period, the indoor blower turns on with a delay. Primary/secondary limits and pressure switches are monitored. If the thermostat opens, the system proceeds to turn off the combustion air blower and then the indoor blower after a selected delay.
Abnormal Heating Mode
Several abnormal conditions are described:
- Flame Failure: Gas valve OFF, blower ON. Sequence holds until no flame is sensed or power is interrupted/reset. DIAG. CODE: 1-FLASHING / 2-OFF.
- Self-Check Failure: Gas valve, comb. blower, and indoor blower OFF. Remove power to reset. DIAG. CODE: BOTH ON.
- Flame Roll-Out Open: Gas valve, comb. blower, and indoor blower OFF. Sequence holds until roll-out switch closes or thermostat resets. DIAG. CODE: 1-ON / 2-FLASHING.
- C.A.B. Pressure Switch Open: Gas valve, comb. blower, and indoor blower OFF. Sequence holds until pressure switch closes or thermostat resets. DIAG. CODE: 1-OFF / 2-FLASHING. If the pressure switch watchguard condition is met (5-minute reset period incomplete), the system may enter a 60-minute watchguard.
- Ignition Sequence Failed 5 Times: Gas valve OFF, comb. blower ON, indoor blower ON. If flame sense fails 5 times during one heat demand, the system enters a 60-minute watchguard. DIAG. CODE: 1-ALT. FLASHING / 2-ALT. FLASHING.
- Limit Open: Gas valve and comb. blower OFF. Indoor blower ON until limit closes. DIAG. CODE: 1-FLASHING / 2-ON. If the primary limit opens 5 times during one heat demand, the system enters a 60-minute watchguard.
Cooling Sequence of Operation
LED remains unchanged (slow flash rate) throughout the cooling cycle. When the thermostat calls for cooling, the compressor contactor and system fan energize at cooling speed after a 0-second delay, with the ACC terminal energized. When the thermostat opens, the compressor turns OFF, and the system fan and ACC terminal turn OFF after 0 seconds.
Manual Fan Sequence of Operation
LED remains unchanged (slow flash rate). Manual fan selection is made at the thermostat. The control energizes the system fan at continuous speed, and the ACC terminal is energized.
- Thermostat Calls for Heat: If NO, the system fan switches to cooling speed, and the ACC terminal remains energized.
- Thermostat Calls for Cooling: If YES, the system fan switches to heating speed after the ignition sequence, and the ACC terminal remains energized. The system fan remains on at heat speed until the selected delay off time is complete.
- Continuous Speed Note: For 80MGF(X)-1/3 units wired with a continuous fan jumper, continuous speed is heating speed. For other 80MGF(X)-1/3 units and all 80MGF(X)/G24M(X)-2/4/6 units, continuous speed is low speed. The system fan switches to continuous speed and energizes the ACC terminal, both remaining on until the manual fan is switched off at the thermostat.
