THERMAL ECONOMIZER

Air-conditioning apparatus; Air-conditioning apparatus; Air-conditioning apparatus and installations; Air-conditioning installations; Air-conditioning, air cooling and ventilation apparatus and instruments; Air conditioning apparatus; Air conditioning apparatus and installations; Air conditioning installations; Air conditioning units; Heat exchangers not being parts of machines; Heat exchangers, other than parts of machines; Heat generators; Heating apparatus for solid, liquid or gaseous fuels; Heating boilers; Heating elements; Heating furnaces; Heating installations; Heating systems for residential and commercial buildings comprised of boilers, valves, pipes, manifolds, control panel switches, and electrical wire, all sold as a unit; Heating units for industrial purposes; Ventilating fans for commercial and industrial use; Ventilating fans for industrial purposes; Boilers for heating installations; Central air-conditioning installations; Central heating radiators; Central heating boilers; Drying apparatus for use in heating, ventilation systems, air conditioning systems and refrigeration systems; Economisers, namely, devices for warming feed water in heating boilers; Filters and filtering devices for air and gas conditioning; Hot-air space heating apparatus; Radiators; Radiators; Space heating apparatus