HVACopediaGoodman · Furnace
EE8 High-stage pressure switch closed at start of heating cycle
What the control is telling you
On a two-stage furnace the high-stage pressure switch circuit is already closed at the start of a heat call. The furnace runs on low stage only (inducer still operates). Flowcharts call this code E8.
Applies to: Goodman/Amana two-stage 96% furnaces GM9C96, GC9C96, AM9C96, AC9C96
Likely causes
- High-stage pressure switch contacts stuck closed
- Short in the pressure switch circuit wiring
Test and repair steps
- Power off, remove the wires from the high-stage pressure switch and ohm the contacts with the inducer off - they must be open.
- Replace the high-stage pressure switch if the contacts are closed with no vacuum.
- If the switch is good, find and repair the short in the switch wiring.
- Retest a high-fire call (W1+W2) and confirm the furnace stages up.
Settings for these units
Normal status displays (7-segment) · Goodman/Amana GM9C96/AM9C96
| Mode | Display |
|---|---|
| Idle | IdL |
| Continuous fan | FAn |
| Cooling, low stage | 1AC |
| Cooling, high stage | 2AC |
| Gas heat, low stage | gH1 |
| Gas heat, high stage | gH2 |
| Factory (OEM) test mode | EOL |
These are normal operating displays, not fault codes.
Minimum recommended filter size · Goodman/Amana GM9C96/AM9C96
| Configuration | Size code | Minimum filter |
|---|---|---|
| Upflow | *0403A* | 1 - 16 x 25 side or 1 - 14 x 24 bottom return |
| Upflow | *0603A* | 1 - 16 x 25 side or 14 x 24 bottom return |
| Upflow | *0603B* | 1 - 16 x 25 side or bottom return |
| Upflow | *0803B* | 1 - 16 x 25 side or bottom return |
| Upflow | *0804B* | 1 - 16 x 25 side or bottom return |
| Upflow | *0804C* | 1 - 16 x 25 side or bottom return |
| Upflow | *0805C* | 1 - 16 x 25 side or bottom return (see note 1) |
| Upflow | *0805D* | 2 - 16 x 25 side or 1 - 20 x 25 bottom return (see note 1) |
| Upflow | *1004C* | 2 - 16 x 25 side or 1 - 20 x 25 bottom return |
| Upflow | *1005C* | 2 - 16 x 25 side or 1 - 20 x 25 bottom return |
| Upflow | *1205D* | 2 - 16 x 25 side or 1 - 24 x 24 bottom return |
| Downflow | *0403A* | 2 - 10 x 20 or 1 - 14 x 25 top return |
Note 1: with a cooling unit over 4 tons use 2 - 16 x 25 filters on two side returns or a 20 x 25 on the bottom return.
Upflow at 1800 CFM or more: use two side returns or one side plus bottom.
Models that show this code
6 models in Goodman/Amana GM9C96/AM9C96
Other codes on the same units
- EE3 High (primary) limit open
- EE4 Flame sensed with no call for heat
- EE5 Open fuse (short in low voltage wiring)
- EE6 Low flame signal
- EE9 High-stage pressure switch did not close
- EEA Reversed line polarity or grounding error
- EEC Internal gas valve error - valve energized when it should not be
- EEE Internal control fault (IRQ loss)
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Source: Goodman RS6612020r1 (GM9C96/GC9C96/AM9C96/AC9C96 service), 2 Stage Troubleshooting Codes, p.36; Error Code E1, E2 flowchart p.40. Summarized in our own words; check the original manual for your model.
Homeowner looking at this code? See what it means for you and when to call a technician.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.