Dryer. I too am having this problem
Ignites, flames for a few seconds then shuts off. After a few minutes the click from the thermostat resetting on the right top of the tube.
I've replaced both thermostat switches (Manual (bottom left) and Auto (top right)), tested them and the flame detector sensor and they all work just fine. They open the circuit when heated and close when cooled off (if thats the correct way to describe it).
What I was wondering is... what is the flame supposed to look like when it ignites? Should it be streamlined like the afterburner on a jet, shooting down the length of the tube? Mine kind of baloons out right at the ignition point and it looks to me like the flame front could be too close to the thermostat hence why it's tripping it and killing the flame.
Now according to the service manual; it says...
"When measuring Valve 1 Voltage, More than AC 90V? If "NO" then check "Thermostat High Limit Safety" If "YES" proceed to check for the Igniter operating. If Igniter works check Valve 2"
My voltage is lower than 90 Volts on valve 1, but I'm not sure which thermostat they consider the "High Limit Safety" I've changed them all.
" When measuring Valve 2 Voltage, value is more than AC 90V? (10 seconds after igniter goes off) If 'YES" then check gas connection / supply. If "NO" then check terminal resistance on valve 1 and 2."
"If resistance is more than 1.5K~2.5K Ohm then change the gas valve."
Both of mine read normal.LG2532W