11 Heating, cooling and ventilation systems and components comprising water pumps, circulators, zone valves, mixing valves, pressure reducing valves, relief valves, air elimination valves, heat exchangers, water tanks, flow meters, and connectors, thermostats and metal castings for use therewith, and sold together as a unit; Heat exchangers, not parts of machines, Hot water tanks; Valves, namely, mixing valves, zone valves, and air elimination valves for use in heating systems; Pumps, namely, water pumps, heat pumps and circulator pumps for use in heating systems; Valves, namely, valves being parts of heating, cooling and ventilation machines; Valves, namely, thermostatically controlled valves