Apparatus for heating, cooling, ventilating, air conditioning and installations thereof; air driers, air re-heaters, gas burners, central heating radiators, chimney flues, drying apparatus, desiccating apparatus; refrigerators and refrigerating equipment; air filtration apparatus and installations; evaporative air coolers, fans, blowers, filters, ducts, controllers, fittings and accessories therefore; ventilation equipment including ventilation hoods