Amana AMSS960803BN Error Code 3 Flashes: Pressure Switch Open
What Does Code 3 Flashes Mean?
Code 3 (3 Flashes) on the Amana AMSS960803BN indicates a pressure switch open condition. The induced draft blower (inducer motor) is running, but the pressure switch has not closed to confirm proper exhaust venting. You will hear the inducer motor running continuously with no ignition.
The pressure switch is a safety device that verifies the inducer motor is creating enough negative pressure to safely vent combustion gases. If the switch does not close, the furnace will not allow gas to flow to the burners. This prevents dangerous exhaust gas buildup in your home.
The most common causes include a blocked, pinched, or disconnected pressure switch hose, a blocked exhaust flue or air intake pipe, and a clogged condensate drain system. Since this is a 96% AFUE condensing furnace, it produces condensate (water) during operation. If the condensate drain becomes blocked, water can back up into the inducer housing and prevent the pressure switch from closing. Clearing the condensate drain is the most accessible DIY fix.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Blocked or pinched pressure switch hose | Most common | ✗ Call a pro → |
| Blocked flue or inlet air pipe | Common | ✗ Call a pro → |
| Blocked condensate drain system | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- Code 3 returns after clearing the condensate drain and checking vents
- The inducer motor sounds unusually loud, weak, or does not start at all
- You cannot locate or access the condensate drain
- You see water pooling around the furnace base
- The pressure switch hose appears disconnected or cracked
Sources
✓ Verified against manufacturer service manual — March 2026