HVACopediaTrane · Furnace
E2.3 1st stage gas valve not powered when it should be (10 times)
What the control is telling you
The control did not see 24 VAC on the MVL (1st stage valve) output when it expected it, 10 times in one heat call, and locks out for an hour. The S8V2 flowchart index words this as valve energized when it should not be; the code table and diagram say not energized.
Applies to: Trane S8V2 (80%, 2-stage, variable speed, Link) and S8B1 / S8X1 / S8X2 (80%, 1- and 2-stage)
Likely causes
- Interrupted 24 V circuit (blower door switch, unplugged harness)
- Power interruption or wind gust during the cycle
- IFC gas valve relay fault
Test and repair steps
- Cycle power and call for 1st stage heat.
- Check that the blower door is closed and all plugs are seated.
- Measure manifold pressure during the call; if the minimum is held, look for intermittent power or wiring breaks.
- If manifold pressure is not held, check and correct incoming supply pressure.
- If wiring and supply are good and the code returns, replace the IFC.
Settings for these units
Clearance to combustibles · Trane S8V2
| Cabinet width | Vertical sides / top | Horizontal sides / top |
|---|---|---|
| 14.5 in. | 0 / 1 in. | 1 / 2 in. |
| 17.5 in. | 0 / 1 in. | 1 / 2 in. |
| 21.0 in. | 0 / 1 in. | 1 / 3 in. |
| 24.5 in. | 0 / 1 in. | 1 / 5 in. |
24 in. front service access.
3 in. in front of the combustion air openings.
Return filter size by cabinet width · Trane S8V2
| Cabinet width | Filter |
|---|---|
| 14-1/2 in. | 1 - 14 x 25 x 1 in. |
| 17-1/2 in. | 1 - 16 x 25 x 1 in. |
| 21 in. | 1 - 20 x 25 x 1 in. |
| 24-1/2 in. | 1 - 24 x 25 x 1 in. |
Filters are field supplied and mounted outside the cabinet.
Over 1600 CFM upflow: return on both sides, one side plus bottom, or bottom only.
- Return filter size by cabinet width · Trane S8B1, Trane S8X1, Trane S8X2
Models that show this code
37 models in Trane S8V2, Trane S8B1, Trane S8X1, Trane S8X2
Other codes on the same units
- E01 Furnace control internal failure
- E2.1 Ignition retries exceeded - flame never proven (1 hour lockout)
- E2.2 Flame recycles exceeded - flame lost after lighting (1 hour lockout)
- E3.1 1st stage pressure switch (PS1) closed when it should be open
- E3.2 1st stage pressure switch (PS1) open when it should be closed
- E3.3 2nd stage pressure switch (PS2) closed when it should be open
- E3.4 2nd stage pressure switch (PS2) open when it should be closed
- E04 Open limit (main limit, rollout or reverse airflow)
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Source: Trane FNR-SVX003A-EN (S8V2 installer's guide) - section Integrated Furnace Control Display Codes, Table 37 Error codes; Trane FNR-SVX003A-EN (S8V2 installer's guide) - section Troubleshooting (flowcharts); Trane 18-CE14D1-1A-EN (S8B1/S8X1/S8X2 installer's guide) - section Integrated Furnace Control Display Codes, Error Codes. 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.