QUESTION: How does the JAO Opener work? ANSWER: The piston has a heat sensitive gel inside which expands as the temperature in the cold frame rises, thus pushing open the hinged door of the cold frame.
I bought my first automatic vent opener four years ago. I finally had to replace the piston last year. I have a total of four now and just ordered two more for a new coldframe this year. I learned to lubricate the piston for longer service after the first one failed. Please offer replacement pistons again. I haven't seen them in the catalog for three years. If you offer replacement pistons again, my rating will go up to five stars.