These “top of the line” controls will open and close greenhouse vents automatically without electricity. The vent openers convert energy from the warmth of the sun into mechanical energy to open vents. The hotter it gets, the wider the vents are opened.
Materials:The vent controls are made from the best corrosion resistant materials: brass, stainless steel and satin-anodized aluminum. They are designed to give many years of service, are covered by a 2-year guarantee, and can be repaired should the need arise.
Capacity: The vent opener can exert a force of 14 lbs. at the point where it is attached to the vent. A threaded thumb screw can adjust the opener to start opening the vent at temperatures between 55º F and 75º F. Maximum opening of 12" is reached at approximately 20º F above the starting temperature.
Openers can be installed in a series on a long vent to replace worn out electric vent motors. The adjuster bolt can equalize the loading so the lifters work in unison.
Installation: Easy to install with screws: top arm to vent, bottom arm to greenhouse frame. Illustrated directions included. Openers are about 12" long and fit neatly up close to the glass.
Solar-Powered Vent Openers
How they work: The opener has a metal cylinder containing a mineral wax which expands with heat. This pushes a piston that opens the vent via a leveraged arm. As the temperature cools, the wax shrinks and a strong spring closes the vent and resets the piston. Opening and closing are gradual adjustments, allowing just the right amount of air flow for cooling.