The L9 error code on a Mitsubishi Electric Ecodan Air Source Heat Pump indicates a low water flow rate in the primary pipework circuit. This could be due to: Water circulation issues, Air in the circuit, and A zone valve or pump that isn't energizing You can try looking for restrictions in the water circuit, such as damaged pipework or valves or flexes that may be kinked. An L9 Error Code can occur on a Mitsubishi Electric Air Source Heat Pump when a Flow Sensor or Flow Swit

One of the first lessons that air source heat pump owners learn is that it costs less to keep your heat pump running all the time, day and night than it does to turn it off and on. Air source heat pumps have a lower flow temperature (the temperature of the water that they pump through your system) than gas boilers, which makes them much more energy efficient. They’re designed to keep your home at a constant temperature rather than pumping out a lot of heat quickly. You'll sav