Air Conditioning Problems - Switching off

The unit appears to switch itself off and or blows cold air, usually when in heating mode, and is sometimes accompanied by a “whooshing” sound. When in heating mode Air Conditioning units extract the heat from outside and using a combination of refrigerant gas and pressure bring it inside. This is efficient to an outside temperature as low as –7deg. However to prevent the outdoor unit freezing up, at such low temperatures, it has to keep itself warm and enter a defrost cycle occasionally. To do this it stops heating for a short period and sends the heat outside to defrost the outdoor unit.