3 flashes Pressure switch stuck open

What the control is telling you

The inducer runs but the pressure switch never closes within 5 minutes, so the control goes into a 1-hour lockout. The inducer keeps running with no heat.

Applies to: GMES9, GCES9, AMES9, ACES9, VMES9, VCES9 (single stage, 92% and 96%)

Likely causes

• Pressure switch hose blocked, pinched or connected wrong
• Blocked flue or inlet air pipe, blocked drain, or weak inducer
• Wrong switch setpoint or bad contacts
• Loose or wrong wiring

Test and repair steps

1. Turn off power before repairs.
2. Inspect the switch hose and fix or replace it.
3. Check flue and inlet piping for blockage, length, elbows and termination. Check the drain system.
4. Correct the switch setpoint or contact movement, or replace the switch with the right part.
5. Tighten or fix the wiring connection.

Settings for these units

• Normal status displays (7-segment) · Goodman/Amana GM9S96/AM9S96
• Normal status displays (7-segment) · Goodman/Amana GM9S80/AM9S80
• Normal status displays (7-segment) · Goodman/Amana GM9C96/AM9C96
• Minimum recommended filter size · Goodman/Amana GM9C96/AM9C96

Models that show this code

57 models in Goodman/Amana *MES9 single-stage

Other codes on the same units

• 1 flash Lockout - three failed ignition tries
• 2 flashes Pressure switch stuck closed
• 4 flashes Primary or auxiliary limit open
• 5 flashes Flame sensed with no call for heat
• 6 flashes Rollout limit open or control fuse blown
• 7 flashes Low flame signal
• 8 flashes Igniter relay fault
• 9 flashes Twinning fault