Error code reference
Trane Furnace Error Code 7 Flash
External gas valve circuit error
External gas valve circuit error — 24 volts is present at the gas valve when it should not be present.
First step from the service manual
Turn comfort control to OFF position; check if 24 VAC nominal voltage is present between red lead at gas valve connection to chassis ground.
The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.
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- Step-by-step tests with expected resistance, voltage, and continuity values
- Wiring diagram references and connector pinouts from the OEM service manual
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