GB1355645A - Heat pump arrangements - Google Patents

Abstract

1355645 Automatic control of temperature TEMPERATURE Ltd 25 June 1971 [25 March 1970] 14618/70 Heading G3R [Also in Division F4] A heat pump arrangement for controlling the temperature of air in a space or room, includes a circuit comprising a compressor 1, a first coil 9 adjacent a fan 10, a second coil 5 adjacent a water-circulating coil 6 and a reversing valve 4. Time delay means are provided in the electric control circuit to ensure that the reversing valve does not change over while the compressor is operating or for a finite time after stopping of the compressor. In the embodiment shown, power is supplied by, a line 21 and fed through a short delay relay contact 22 to a line 23 leading to the reversing valve. The circuit also includes first and second thermostatically controlled change-over contacts 24 and 25, a longer delay relay 27, a thermal delay relay 31, and lines 29 and 33 which may be selectively connected to the compressor via a line 34 and the contact 35. The contacts 24 and 25 define "off", "heating" and "cooling" modes of operation. In operation, at the commencement of heating or cooling, the reversing valve is positioned a finite time before the compressor is started. At the end of the said heating or cooling periods, the compressor is immediately cut off, followed by a finite time later, the changing-over of the reversing valve. In a second embodiment Fig. 3, (not shown), the compressor starts simultaneously with the changing-over of the reversing valve, but stops before a delay relay is de-energized to cause the reversing valve to change back.