Amana AMSS960803BN Error Code 3 Flashes: Pressure Switch Stuck Open
What Does Code 3 Flashes Mean?
Three flashes on the Amana AMSS960803BN Integrated Control Module mean the pressure switch circuit did not close after the induced draft blower started. You will typically hear the inducer motor running continuously with no ignition, because the board will not open the gas valve until the switch proves adequate venting draft.
The pressure switch is a safety device that confirms the inducer is pulling enough negative pressure to carry exhaust gases safely out of the home. Because the AMSS960803BN is a 96% AFUE condensing furnace, it produces liquid condensate as it runs, and anything that restricts the exhaust path or lets condensate back up will keep the switch from closing. The most common causes are a blocked, pinched, or disconnected pressure-switch hose, a blocked flue or combustion-air intake pipe, a clogged condensate drain, or a weak inducer motor.
This code is the counterpart to the two-flash code on the same board. Three flashes means the switch fails to close while the inducer runs — a draft or blockage problem — whereas two flashes (Pressure Switch Stuck Closed) means the switch is already closed before the inducer starts. Because isolating the cause involves the venting system, condensate path, and inducer, Amana lists this as professional service on this model.
What You'll Notice
- The inducer motor runs continuously but the burners never light
- The diagnostic LED flashes three times, pauses, and repeats
- No heat, even though you can clearly hear the furnace draft motor working
- In cold or snowy weather the code may appear after the outdoor vent pipes get blocked by snow or ice
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 → |
How This Is Diagnosed
Because the inducer is confirmed running, diagnosis focuses on why the draft is not reaching the switch. A technician inspects the pressure-switch hose for kinks, cracks, blockage, or a loose connection, then checks the flue and combustion-air intake pipes for obstructions, correct length, and proper termination. On this condensing furnace they also check the condensate trap and drain for a clog that could back water into the inducer housing, and they verify the inducer is spinning at full speed. Only after the venting and condensate paths are cleared would the pressure switch setpoint or contacts be tested. A homeowner can safely check the outdoor vent terminations for obvious snow, ice, or debris, but the internal diagnosis is professional work on this model.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- The inducer runs nonstop but the furnace never ignites
- Three flashes persist after the outdoor vent and intake pipes are confirmed clear
- You see or hear water pooling around the base of the furnace, suggesting a condensate backup
- The inducer motor sounds weak, loud, or labored
Frequently Asked Questions
Why does my Amana AMSS960803BN inducer run but the furnace won't light with a 3-flash code?
The inducer is running but the pressure switch is not closing to confirm safe venting, so the board holds off ignition. Common causes are a pinched or blocked pressure-switch hose, a blocked flue or intake, or a clogged condensate drain.
Can snow or ice cause a 3-flash pressure switch code?
Yes. On this 96% condensing furnace the exhaust and intake are usually PVC pipes ending outside, and snow, ice, or debris over them can block the draft enough to keep the pressure switch open. Clearing the outdoor terminations is a safe thing to check.
Is a 3-flash code something I can fix myself?
Beyond checking the outdoor vents for an obvious blockage, this code is listed as professional service on this furnace because it involves the pressure switch, internal venting, and condensate system. A technician should confirm the cause.
Sources
✓ Verified against manufacturer service manual — March 2026