Summer-Winter Thermostat (55-85°F)

Description:

The 2218 Series Pneumatic Room Thermostats are designed for proportional control of pneumatic valves and damper actuators in environmental control systems where a dual presure air main is utilized for seasonal changeover of heating and cooling functions. Their design incorporates a highly sensitive, bimetal, thermostatic element, and a pilot-operated relay with pneumatic feedback for accuracy and stability over the entire operating range. Indexing the thermostat from summer control (reverse acting) to winter control (direct acting), or vice versa, is accomplished by remotely changing the main air pressure supply from 16 psig (summer) to 25 psig (winter). Models are also available that operate on slightly different pressures to replace many competitive devices. These thermostats have a serrated thumb wheel for setpoint adjustment. Models are also available with preassembled internal dial stops. Thermostat covers are available in various styles to meet particular requirements. Cover options include models with a setpoint scale and a thermometer, a setpoint scale only, a thermometer only, or blank. An external setpoint adjustment cover is available on some models, or can be field-installed on covers where desired. Features Factory-calibrated, stainless steel ball-in-seat provides pneumatic feedback for stable, linear operation. Snap-acting (not gradual) changeover from direct action to reverse action operation and vice versa. Easy-to-use throttling range adjustment and recalibration. Adjustable (patented) bimetal shows actual throttling range in both °F and °C. Adjustable 2 to 12 °F (1 to 6.7 °C). Leak-proof, self-closing branch gauge tap. Includes: (2) 1/4" x 3/16" barbed couplings, 20-693 tubing, 20-714 wall plate, 20-711 mounting plate, and mounting screws.