Alton | Thermofor Louver Window Opener Piston Replacement

The Thermofor Louver Vent Replacement Cylinder is designed to restore smooth, automatic operation to your greenhouse louver vent opener. Compatible with Thermofor, Robinsons, and Alton branded louver openers, this replacement cylinder helps maintain proper airflow and temperature control without manual adjustment. Inside the cylinder is a heat-sensitive wax core that expands as temperatures rise and contracts as they cool. This natural movement powers the opening and closing of your louver vents, improving ventilation and protecting your plants from overheating. KEY FEATURES Wide compatibility: Fits Thermofor, Robinsons, and Alton louver vent openers. Restores automatic ventilation: Keeps airflow consistent and responsive to temperature changes. Heat-powered operation: No electricity or batteries required. Replacement cylinder only: No fittings or mounting hardware included. SPECIFICATIONS PRODUCT TYPE: Replacement cylinder COMPATIBILITY: Thermofor, Robinsons, and Alton louver vent openers OVERALL LENGTH: 7 inches METRIC LENGTH: 170 mm INCLUDED: Cylinder only (no fittings) HOW IT WORKS The cylinder uses a wax-filled core that reacts to temperature changes. As the greenhouse warms up, the wax expands and pushes the piston to open the louver vent. When temperatures drop, the wax contracts, allowing the vent to close. This automatic process helps maintain a stable growing environment throughout the day. MAINTENANCE AND CARE Keep the cylinder clean and free from debris to ensure smooth operation. Periodically inspect your louver opener to maintain proper alignment and performance. FREQUENTLY ASKED QUESTIONS What does a louver vent opener cylinder do? It controls the opening and closing of your louver vents using heat expansion, helping regulate airflow and temperature inside your greenhouse. Do I need electricity or batteries? No. The cylinder operates entirely on heat expansion, so it requires no power source. Will this fit my greenhouse vent opener? This cylinder is compatible with Thermofor, Robinsons, and Alton louver vent openers. Always confirm your model before purchasing. When should I replace the cylinder? If your louver vent no longer opens or responds slowly to temperature changes, replacing the cylinder can restore proper function.