Amana AMVC960803BN Error Code EEF: Condensate Switch Open
What Does Code EEF Mean?
The AMVC960803BN is a high-efficiency condensing furnace, so it deliberately cools the flue gases far enough to pull water (condensate) out of them. That water collects in a drain pan and leaves through a PVC drain line and trap. A condensate overflow switch — an auxiliary safety switch — watches the water level. Code EEF is set when that switch OPENS because the water level has risen too high, and the control shuts the furnace down to prevent water damage and to keep water out of the combustion and venting components.
When the drain cannot carry water away fast enough, the level rises until the switch trips. The most common reasons are a clogged condensate drain line or trap (algae, sludge, or mineral buildup) and a high water level in the evaporator-coil drain pan above the furnace when the system shares drainage with an air conditioner or coil. Until the water level drops and the drain is cleared, the furnace will not run.
The same backed-up water that trips this switch can also reduce inducer draft, which is why a clogged drain is a known contributor to the low- and high-stage pressure-switch codes on this board — EE2 (Low Stage Pressure Switch Open) and EE9 (High Stage Pressure Switch Open). Unlike a stuck pressure switch, EEF points squarely at the condensate drainage path rather than the vent pipes themselves.
What You'll Notice
- The furnace shuts down and will not restart
- The dual 7-segment display reads EEF
- Standing or gurgling water near the furnace or in the drain line
- A full or slow-draining condensate trap, or water dripping from the drain-pan area
- Water pooling around the base of the furnace or under the indoor coil
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Clogged condensate drain line or trap | Most common | ✗ Call a pro → |
| High water level in evaporator coil drain pan | Most common | ✗ Call a pro → |
How This Is Diagnosed
A technician traces the condensate path in order to find where water is backing up. They check the drain line and trap for a clog (algae, sludge, or scale), confirm the trap is not air-locked or dry, and inspect the evaporator-coil drain pan and its outlet for standing water — especially where the furnace shares drainage with a cooling coil. The overflow switch and its wiring are then checked to confirm it opened on a real high-water condition rather than a fault.
Once the source is found, the technician clears the blockage, verifies water flows freely to the termination, and confirms the switch resets as the level drops. This condensate-system service — clearing the trap and pan and confirming proper drainage on a sealed condensing furnace — is handled by a qualified technician rather than as a homeowner repair for 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 display shows EEF and the furnace will not restart
- There is standing water in the condensate trap, drain line, or coil drain pan
- Water is leaking or pooling around the furnace or the indoor coil
- EEF returns shortly after the furnace is restarted
- You are unsure where the condensate drain runs or where it terminates
Frequently Asked Questions
Why does a furnace produce water in the first place?
As a condensing furnace, the AMVC960803BN extracts extra heat by cooling the exhaust until moisture condenses into water. That water is normal and is meant to drain away; EEF appears when it cannot drain fast enough.
Will EEF clear on its own?
The switch can reset once the water level drops, but if the drain is clogged the level will rise again and the code will return. The underlying blockage needs to be cleared for a lasting fix.
Could the same clog cause other codes?
Yes. Water backing up in a condensing furnace can also reduce inducer draft and contribute to pressure-switch codes such as EE2 or EE9, so a technician typically checks the drain and the venting together.
Sources
✓ Verified against manufacturer service manual — March 2026