Short cycling

Short cycling is repeated brief on-off operation, where a heat pump starts, runs for a short period, stops and then starts again more often than the heating load or control sequence should require. Some cycling is normal, especially in mild weather when the home needs less heat than the heat pump can steadily supply at its lowest output. Frequent short cycles can point to poor load matching, limited modulation range, low system water volume, flow problems, control behaviour, defrost conditions or a fault that needs proper diagnosis. In heat pump documents and support conversations, the term may sit near heat loss, minimum output, emitter design, buffer vessels, flow rate, water volume, room thermostats and weather compensation. It should not be read as a single fault code, proof that the heat pump is oversized, an instruction to change controls or evidence that a buffer vessel is always needed.