Fault route
TIG Gas Flows but HF Missing Diagnostic
A TIG sequence route for machines where gas opens but high-frequency arc start is absent.
Quick Answer
Gas flow proves the torch/timing/gas output path is partly alive. If HF is missing, check HF command from the control board, then HF relay, HV pack and arc-start output path.
Diagnostic path
Torch input → gas output works → HF command → HF relay → HV pack → torch HF output.
Evidence table
Gas works but no HF command: control timing/output issue. HF command exists but no HF: HF board or HV path. HF exists but no arc: transfer/output route, not no-HF route.