Why is the circulation pump on the LAxx / LIxx / SIxx / WIxx model of heat pump shutting down for around 40 mins even when there seems to be a demand for heat? (Applies to L12 or higher version software).

Version L12 or higher software has the option of “Pump optimisation” and if enabled, will reduce the circulation pump running time for energy efficiency, putting a 40 min delay before starting the circulation pumps & heat pump.

This optimisation setting is based on outside temperature and if set too low, the pump will not be running for 40 mins after heating completed, in cold weather. Customers may notice radiators cooling down for instance. 

To alter the setting, Hold Menue+Enter together then go to->Settings -> Pump Control -> “Optimisat.heating pump”. Change the outdoor temperature to a higher value, so this delay behaviour only happens in warmer weather.