Trane · Furnace

E7.1 1st stage gas valve (MVL) powered with no call

Critical severity Trane S8V2Trane S8B1Trane S8X1Trane S8X2

What the control is telling you

24 V is present on the gas valve circuit when the control is not asking for heat - an external wiring fault or failed board.

Applies to: Trane S8V2 (80%, 2-stage, variable speed, Link) and S8B1 / S8X1 / S8X2 (80%, 1- and 2-stage)

Likely causes

Miswired valve circuit or back-feed from field wiring
Failed IFC relay

Test and repair steps

Turn the thermostat to OFF.
Measure 24 VAC from the red lead at the gas valve to chassis ground.
If voltage is present, find and correct the wiring fault, then cycle power.
If the code persists with correct wiring, 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

S8B1A026M2PSABS8B1A040M3PSABS8B1B040M2PSABS8B1B060M3PSABS8B1B060M4PSABS8B1B080M4PSABS8B1C080M5PSABS8B1C100M5PSABS8B1D120M5PSABS8V2A040M3PCBS8V2A040M3PDS8V2B060M4PCBS8V2B060M4PDS8V2B080M4PCBS8V2B080M4PDS8V2C080M5PCBS8V2C080M5PDS8V2C100M5PCBS8V2C100M5PDS8V2D120M5PCBS8V2D120M5PDS8X1A026M2PSABS8X1A040M3PSABS8X1B040M2PSABS8X1B060M3PSABS8X1B060M4PSABS8X1B080M4PSABS8X1C080M5PSABS8X1C100M5PSABS8X1D120M5PSABS8X2A040M3PSABS8X2B060M3PSABS8X2B060M4PSABS8X2B080M4PSABS8X2C080M5PSABS8X2C100M5PSABS8X2D120M5PSAB

Other codes on the same units

E05 Flame sensed when no flame should be present
E6.1 120 V polarity reversed
E6.2 Ground not detected
E6.3 Igniter open or igniter relay fault
E7.2 Redundant relay (HLO output) on with no call
E08 Low flame signal (still running)
E11 Gas valve relay / valve circuit fault
E12 Control fuse open

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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.