Automatic damper means for air ducts
Automatic temperature compensated boiler thermostat
Cascaded control apparatus for controlling unit ventilators
Direct drive air register damper
Electric control device for a central heating boiler
Fireplace heating system
Four-terminal zone thermostat
Heating system for building structures
Heating system for building structures
Heating system of the type for apartments or offices in building
Multi-blade automatic air register damper
Self-operated air register damper
Solenoid operated damper blades
Thermostat system
Zone heat control