Amana AMVC960803BN Error Code EE9: High Stage Pressure Switch Open
What Does Code EE9 Mean?
Error code EE9 on the Amana AMVC960803BN means the high-stage pressure switch failed to close during a high-stage call for heat. The induced draft blower is running, and low-stage operation continues normally, but the furnace cannot transition to high-stage heating. You will notice reduced heat output, especially during cold weather when more capacity is needed.
The high-stage pressure switch closes when the inducer reaches high speed and produces enough negative pressure in the flue. If the flue system is partially obstructed, the inducer cannot create enough draft to pull the switch closed. A blocked or kinked pressure switch hose prevents the draft pressure from being transmitted to the switch diaphragm. A blocked condensate drain or inlet air pipe can also reduce draft. A weak induced draft blower motor that cannot reach high-stage RPM will produce insufficient pressure. If all the mechanical factors check out, the switch itself or its wiring may be faulty.
A technician will inspect the venting system, measure the pressure switch differential with a manometer, and test the switch contacts to identify which component is the cause.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- EE9 is present and the furnace is limited to low-stage heating — a technician must inspect the flue system and measure draft pressure to determine the cause
- The pressure switch hose is intact but the switch still does not close — the switch must be tested and replaced if the set-point is incorrect or the diaphragm has failed
- The induced draft blower motor is running slowly or making unusual noise — motor replacement requires professional service
Sources
✓ Verified against manufacturer service manual — March 2026