2+5 Invalid model selection or setup error

What the control is telling you

If it flashes only 4 times at power-up, model plug PL4 is missing and the board is using the model stored in memory. If it flashes continuously, there is a setup error.

Applies to: ICP F9MAE / G9MAE modulating variable-speed condensing gas furnaces (060, 080, 100, 120 kBtu/h)

Likely causes

• Model plug PL4 missing and no valid model in memory (common on a service replacement board)
• Thermostat call while SW1-1 is ON
• Thermostat call while SW1-6 is ON
• SW1-1 and SW1-6 both ON
• Two different furnace models twinned
• Wrong replacement control - needs modulating board with software V17 or later

Test and repair steps

1. Install the correct model plug PL4 shown on the rating plate.
2. Turn SW1-1 and SW1-6 OFF for normal operation.
3. If twinned, verify both furnaces are the same model.
4. On a replacement control, confirm it is the modulating board with software V17 or later.
5. Cycle power and confirm heartbeat.

Models that show this code

6 models in ICP (F/G)9MAE Modulating Furnace

Other codes on the same units

• 1+2 Blower on after power-up (normal)
• 1+5 Blower motor lockout
• 2 Pressure switch did not open
• 3 Low pressure switch did not close or reopened
• 3+5 Gas valve fault (modulating valve)
• 4 Limit circuit fault
• 4+1 Blower motor fault
• 4+2 Inducer motor fault