interlock

drain not conneccted means the senser is not pluging or the drain is not full the water fill the drain frome the burner hole and shure the drain over flow and check the drain vasle not full of waste
about nebulizer
u can check the magnat is near to sensor and you can tray to move the magnat up and down

All the interlock shown that : air/ C2H2 , N2O , drain , nebulizer and burner assembly are connected but i've disconnected everthing 

- i rest the instrument but it still  show that everything is connected

- burner head interlock disconected