FieldBench
Trane codes

Trane

Ignition / flame

Lockout

Prove / valve / HSI

Trial without flame, or unexpected flame. Confirm the ComfortLink text — do not map it to S9V2 E2.1 / E5.x by habit.

Walk Ignition / flame in Diagnose

Sign in for the next measurement

First check

1 Data pair, not 24 V

On Trane XC95m indoor/outdoor comm is a data pair (AB, S1/S2, U, ComfortBridge, ComfortLink — whatever THIS plate uses). It is not a 24 V Y. Check polarity, continuity, and that nobody landed it on R/C. HSI, gas, rod, ground.

Expect: Pair continuous, not shorted to chassis, polarity per the diagram.

The rest of the walkthrough is Diagnose.

On the plates

  • HSI, gas, rod, ground.
  • Modulating valve offset — a valve stuck at minimum never looks like a healthy light-off.
  • Shut the cock on unexpected flame.

Plates that use Ignition / flame