EE9 High-stage pressure switch did not close

What the control is telling you

On a two-stage furnace the high-stage pressure switch does not close when the inducer goes to high speed. The furnace keeps running on low stage only. Flowcharts call this code E9.

Applies to: Goodman/Amana two-stage 96% furnaces GM9C96, GC9C96, AM9C96, AC9C96

Likely causes

• Pressure switch hose blocked, pinched or connected wrong
• Blocked flue or intake, or vent too long / too many elbows
• Blocked condensate drain
• Weak inducer on high speed
• Bad switch or loose wiring

Test and repair steps

1. Inspect the high-stage pressure switch hose and repair or replace it.
2. Check the flue and intake piping for blockage and for correct length, elbows and termination.
3. Check the drain system and front cover pressure switch.
4. With a manometer, compare the negative pressure at high inducer speed with the switch rating; enough vacuum but open switch = replace the switch.
5. Check inducer voltage and amps; replace the inducer if it cannot pull enough vacuum.
6. Tighten or correct the pressure switch wiring and retest a high-fire call.

Settings for these units

Normal status displays (7-segment) · Goodman/Amana GM9C96/AM9C96

These are normal operating displays, not fault codes.

Minimum recommended filter size · Goodman/Amana GM9C96/AM9C96

Note 1: with a cooling unit over 4 tons use 2 - 16 x 25 filters on two side returns or a 20 x 25 on the bottom return.

Upflow at 1800 CFM or more: use two side returns or one side plus bottom.

Models that show this code

6 models in Goodman/Amana GM9C96/AM9C96

Other codes on the same units

• EE4 Flame sensed with no call for heat
• EE5 Open fuse (short in low voltage wiring)
• EE6 Low flame signal
• EE8 High-stage pressure switch closed at start of heating cycle
• EEA Reversed line polarity or grounding error
• EEC Internal gas valve error - valve energized when it should not be
• EEE Internal control fault (IRQ loss)
• EEH Twinning error