Hi Dangle. Sorry mate but I have the same derivative machine as yours I am pretty sure. Rebadged jobbies
Anyway, when depressing the torch trigger and HF starts, regardless of connections, gas or anything else, the amps display. Sounds to me like yours is faulty
Here's Lexi's thread about his not arcing - turned out to be a wire not plugged into the circuit board. Well worth lifting the cover off to see if anything is loose.