Keeprite E9 Error Code

What does Keeprite E9 mean?

The IGC board displays 9 LED flashes to signal a pressure switch or PSR relay fault, sometimes described as a software-level lockout. The IGC has detected an inconsistency between pressure switch states — for example, a high-pressure switch showing closed while a low or medium-pressure switch is showing open — indicating a switch mismatch, wiring fault, or failed PSR relay.

Symptoms

• IGC board LED flashes 9 times repeatedly with no heat output
• Inducer motor may run but gas valve does not open
• Fault may appear intermittently, especially under gusty or varying pressure conditions
• Unit was previously displaying 3-flash pressure switch codes before escalating to E9

Common causes

• Pressure switch stuck open preventing the PSR relay from energizing
• Condensate drain blockage creating back-pressure that holds the pressure switch open
• PSR (pressure switch relay) coil failure or stuck relay contacts
• Incorrect pressure switch wiring — leads swapped or connected to wrong terminals
• Low inlet gas pressure causing the combustion air pressure switch to read incorrectly

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Diagnostic steps

1. Check the condensate drain and pressure tubing

   Inspect the condensate drain for blockage and the pressure switch tubing for kinks, disconnections, or water traps. Clear any obstructions and verify all tubes are firmly seated on their fittings.

2. Test pressure switch operation

   With power off, disconnect the pressure switch tubing and apply suction with a vacuum pump or manometer to verify the switch opens and closes at its rated set point. A switch that does not actuate at the specified pressure must be replaced.

3. Inspect PSR relay wiring and contacts

   Locate the PSR relay on or near the IGC and verify wiring connections are correct and tight. Check relay coil resistance with a multimeter; an open coil reading indicates a failed relay.

4. Verify pressure switch wiring terminations

   Cross-reference wiring against the unit wiring diagram. Confirm leads are not swapped between low, medium, and high-pressure switch terminals on the IGC connector.

5. Cycle power and observe inducer startup sequence

   After correcting any found issues, restore power and initiate a heat call. Verify the inducer starts, pressure switch closes within the expected time, and the IGC advances to ignition without displaying a 9-flash code.

When to call a professional

Diagnosing a 9-flash PSR relay or pressure switch mismatch fault requires a wiring diagram, manometer, and methodical switch testing that most field technicians handle but is beyond typical owner-level troubleshooting. Engage a licensed HVAC technician if pressure switch replacement or PSR relay replacement is needed, or if the fault recurs after drain and tubing checks.