Circuit reference

TIG Gas Solenoid Control Path

A general TIG gas-valve control reference for timing, no-gas and stuck-gas faults.

Quick Answer

The TIG gas solenoid path should be split into torch input, timing logic, gas output driver, solenoid coil, gas supply and post-flow control.

A clicking gas valve does not prove PWM/current output is enabled.
No gas can be caused by torch input, timing command, output driver, solenoid coil or external gas supply.
Gas stuck on can be caused by a stuck solenoid, stuck output driver or incorrect timing logic.

Layer	Expected evidence	Fault clue
Torch input	Valid trigger reaches timing control.	No gas/HF/current if trigger absent.
Timing logic	Pre-flow and post-flow command gas output.	Wrong timing or no command.
Output driver / relay	Drives solenoid coil.	No voltage to coil or stuck output.
Solenoid coil	Opens valve when energized.	Voltage present but no gas; or valve stuck open.
Gas supply	Gas available upstream.	No gas despite electrical command.
Post-flow control	Gas continues briefly after current stops.	Post-flow absent or gas never stops.

Related records

Open based on gas symptom.