GB1236834A - Improvements in pump operated central heating systems - Google Patents

Abstract

1,236,834. Water heaters. JUNKERS & CO. G.m.b.H. 29 Jan., 1969 [2 Feb., 1968], No. 4903/69. Heading F4A. In a pump-operated central heating system of the kind having a boiler which serves as a heat source selectively for the central heating system or for a domestic water heater, the water circulation being directed either to the heating elements of the central heating system or to the domestic water heater by means of a three-way valve controlled by a thermostat whose temperature senser is arranged in the water space of a domestic water reservoir serving as the domestic water heater, the reservoir is an independent unit, and the three-way valve and thermostat are arranged solely on the unit. This facilitates the addition of a domestic water heater to an existing central heating system. The central heating system shown comprises a gas-fired boiler 10 supplying radiators 16, the circulating pump 23 being located in the main return line 22. Domestic hot water is supplied from a unit 11 comprising a hot water tank 45, circulating flow being diverted from the radiators 16 to a calorifier 18 by a three-way valve 14 under the control of a priority switch 38 and a thermostat 34 comprising a temperature senser 35 and a switch 36. The priority switch 38 causes the gas flow regulator 42 to operate at a higher level when the circulating water is flowing through the calorifier 18 instead of the radiators 16. If the temperature of the circulating water exceeds a predetermined value, a switch 44 of a thermostat 43 renders the boiler 10 inoperative. The three-way valve 14 and the thermostats 34, 43 are arranged on the housing 47 of the hot water tank 45 so that the domestic hot water unit 11 is separate from the boiler 10, the valve and thermostats preferably being mounted on a wall of the housing, facing the boiler. A hard foam insulation 48 is provided. An adjustable by-pass valve 26 can be provided to afford a minimum flow of circulating water for controlling a water-deficiency safety device. The boiler 10 is provided with a thermostatically controlled by-pass valve 25. The unit 11 may be inverted, the long cold water inlet pipe 29 and the short hot water outlet pipe 30 then being interchanged. There may be more than one domestic hot water tank, connected either in parallel or in series with each other.