gas stove and heater

[burleyboy]

hi, got 1972 airstream home ok after parked 7 years, and thanks to all for advice.
found that lpg tanks were nearly full so turned one on. however couldn't get either the stove or heater to light. found pet cocks under stove and opened each. tried auto spark on heater without lighting pilot. couldn't get stove to light or even hint of gas.

is there another valve that needsto be opened. opened tank, turned selector to that tank. could hear gas hissing in line and could smell just a hint of sulphurous odor.

any advice appreciated.

david