Amana AMVC960803BN Error Code EE9: High Stage Pressure Switch Open
What Does Code EE9 Mean?
When the AMVC960803BN calls for high-stage heat, the induced-draft blower ramps to high speed and must pull enough negative pressure to prove safe venting at that firing rate. The high-stage pressure switch is supposed to close in response. Code EE9 is set when that switch does NOT close: the control keeps the furnace on low stage rather than firing high, so you get heat but at reduced capacity — most noticeable on cold days when full output is needed.
This two-stage condensing furnace proves each stage with its own pressure switch. EE9 is the high-stage switch failing to confirm high-fire draft, so only the high stage is disabled while the low-stage switch and burners keep working. That makes EE9 far less disruptive than the low-stage EE2 (Low Stage Pressure Switch Open), which stops ignition entirely. EE9 is the open-side counterpart of EE8 (High Stage Pressure Switch Stuck Closed), where the same switch is instead stuck closed at startup.
Common causes are a partially blocked or restrictive flue or intake pipe that limits high-fire draft, a kinked, cracked, or water-filled pressure-switch hose, a blocked condensate drain that reduces draft, an inducer that cannot reach full high-stage speed, or a faulty switch or loose wiring. A clogged condensate line — the same condition behind the EEF condensate-switch code — can also cut into the draft the high-stage switch needs.
What You'll Notice
- The furnace heats but never steps up to high fire, so it feels underpowered
- Reduced heat output, especially noticeable during very cold weather
- The dual 7-segment display reads EE9
- Longer run times while the home is slow to reach the set temperature
- Normal low-stage startup — the inducer, igniter, and burners all light
Common Causes
How This Is Diagnosed
A technician starts with the venting path that feeds high-fire draft: the exterior exhaust and intake terminations are checked for partial obstructions, the pressure-switch hose is inspected for kinks, cracks, or trapped water, and the condensate drain is checked for a blockage that could reduce draft. These checks isolate the common mechanical causes first.
If the venting is clear, the technician evaluates whether the inducer reaches full high-stage speed and measures the switch against its rated set point to see if it closes on a healthy high-fire draft. A switch that will not close with proper draft is replaced with the correct Amana part, and loose or corroded wiring is repaired. Because this is the combustion venting-safety circuit, the diagnosis belongs to a qualified technician.
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 furnace only runs on low heat and will not step up, with EE9 on the display
- Heat output is noticeably reduced during cold weather
- EE9 remains after obvious vent obstructions and standing drain water are cleared
- The induced-draft blower sounds slow, weak, or unusually loud
- The code appears together with EE8 or the low-stage codes EE1/EE2
Frequently Asked Questions
Can I keep using the furnace with EE9?
It will keep heating on low stage, and the safety system has disabled only the high stage. Have the venting and switch checked soon, though, since reduced draft can point to a flue or drain problem worth correcting.
Why is my Amana furnace not keeping up on cold days with EE9?
EE9 locks the furnace to low stage, so it delivers less capacity than normal. On the coldest days low-stage output alone may not keep pace with the thermostat setting.
Is EE9 the same problem as EE2?
No. EE2 is the low-stage switch failing to close, which stops ignition entirely, while EE9 is the high-stage switch, which only blocks high fire and leaves you with reduced low-stage heat.
Sources
✓ Verified against manufacturer service manual — March 2026