A blowback electrode start (such as all Hypertherm, Thermal, Miller and Lincoln) can not have air flowing before the torch starts......they use the air flow to move the electrode, which ionizes the gas. Any high frequency start torch (older Hypertherm, Thermal, Miller , Lincoln and Esab) designs have preflow....and they will work submerged. High frequency start is used in almost all industral design torches today (read expensive, high duty cycle systems) and blowback start is used in almost all air plasma systems (read, affordable low duty cycle systems)

It looks like you are using a Hypertherm blowback start torch...one of the Powermax units. If it continues to work submerged...thats great! I have heard of others operating them this way. Our engineers do not recomend this, however!

Jim