E05 Flame sensed when no flame should be present

What the control is telling you

The control detects flame with the gas valve supposed to be closed, typically a leaking valve. On the S8X manual this code is printed as e0s.

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

Likely causes

• Gas valve leaking through
• Water or dirt in the valve inlet screen
• Missing drip leg

Test and repair steps

1. Warning: Shut off gas supply before removing the valve.
2. Power off; remove the gas valve and inspect the inlet screen for water or debris.
3. If dirty or wet, have the supply checked for leaks/quality and install a drip leg if missing.
4. Install a new gas valve using a backup wrench and test operation.

Settings for these units

Clearance to combustibles · Trane S8V2

24 in. front service access.

3 in. in front of the combustion air openings.

Return filter size by cabinet width · Trane S8V2

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

• E04 Open limit (main limit, rollout or reverse airflow)
• E4.0 Main high limit open
• E4.1 Reverse airflow limit open
• E4.2 Flame rollout switch open
• E6.1 120 V polarity reversed
• E6.2 Ground not detected
• E6.3 Igniter open or igniter relay fault
• E7.1 1st stage gas valve (MVL) powered with no call