Amana AMVM970803BN Error Code EE9: High Stage Pressure Switch Not Closed
What Does Code EE9 Mean?
Code EE9 means the high-stage pressure switch never closes to confirm high-stage draft while the inducer runs. The furnace protects itself by staying on low stage, so it still heats but cannot reach full high-fire output — a low-severity condition.
The high-stage switch closes only when the inducer produces the stronger vacuum needed for high fire. A blocked or pinched pressure-switch hose, a blocked flue or intake pipe, a clogged condensate drain, or a weak inducer can prevent that, as can a faulty switch.
EE9 is the high-stage version of EE2 (low-stage switch not closing) and the opposite of EE8 (high-stage switch stuck closed at start). Because the causes include venting and drainage, EE9 is diagnosed by a professional even though the furnace keeps running on low stage.
What You'll Notice
- The furnace runs on low stage only and cannot reach high fire, with EE9 displayed
- Reduced heat output on the coldest days
- Possible signs of a restricted flue or intake at the outdoor termination
- Water backing up if the condensate drain is partly clogged
Common Causes
How This Is Diagnosed
A technician inspects the high-stage pressure-switch hose for blockage or pinching, checks the flue and intake piping for blockage and correct termination, verifies the condensate drain is clear, and confirms the inducer can produce the higher vacuum high stage requires.
If venting, drain, hose, and inducer are all good but the switch still will not close, the high-stage pressure switch is replaced and wiring is verified. The furnace remains usable on low stage meanwhile.
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 stays on low stage and shows EE9, especially on cold days
- You see restriction at the flue or intake termination
- Water is backing up, suggesting a clogged condensate drain
- Full high-fire heating is needed and not available
Frequently Asked Questions
Why is my furnace stuck on low fire with EE9?
The high-stage pressure switch is not confirming high-stage draft, so the furnace safely limits itself to low stage. A blocked vent, kinked hose, or clogged drain is often to blame and should be checked by a technician.
Is EE9 an emergency?
No, it is low severity — the furnace still heats on low stage. But since venting or drainage may be involved, have it corrected promptly, especially before the coldest weather.
✓ Verified against manufacturer service manual — March 2026