2 Pressure switch did not open

What the control is telling you

A pressure switch was still closed when it should be open (before the inducer starts).

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

Likely causes

• Obstructed pressure switch tube
• Pressure switch stuck closed

Test and repair steps

1. Check pressure tubes for blockage or water; clean and shake out.
2. Do not blow into a tube while it is connected to the pressure switch.
3. Check the switch opens with the inducer off (ohmmeter); replace if stuck closed.

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+5 Invalid model selection or setup error
• 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