Common error codes for Mitsubishi Ecodan

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 Switch detects low water flow rate on the Primary pipework circuit. The cause is water circulation issues. 

Error Code Text

L9

Description

Flow sensor or flow switch detecting low flow rate on primary circuit

Cause

Water circulation issue, air in the primary circuit, zone valve/pump not energising, flow sensor reading abnormal value

Check Procedure

Check pump/zone valve operation, check connections/wiring of flow sensor and/or switch, check FTC dip switch settings 

Error Code Text

U1

Description

Ecodan High pressure fault

Cause

Usually caused by abnormal water flow on the primary circuit. 

Check Procedure

Check flow rate on flow setter/sensor, check operation of pumps and zone valves, check water pressure and air in the primary water circuit

U8

Description

Ecodan fan issue

Cause

Blockage around fan or motor/circuit board malfunction

Check Procedure

Make sure fan can spin freely, check voltage to motor/ check circuit board voltage levels

Samsung Error Codes 

E101 error code would suggests the data cable between the indoor control panel and external ASHP, it may be the cable has damaged but more likely the terminals have come loose or corroded so worth checking both ends.

E919: A Legionella failure error, which can occur when the unit doesn't reach the desired temperature during a Legionella cycle for the required time set on the controller. This can be rectified by going into service settings and altering the temperature and time frame. Most cylinders only need to be heated to 60 degrees for around 20 minutes once a week to reduce bacteria growth.

A Samsung E911 Error Code can often occur on a Samsung air source heat pump system when there is a water flow issue in the system, more often in the Primary pipework circuit. A blocked filter or partially opened two port zone valve will normally be the main culprit. Both can be rectified with regular maintenance.

E458 error code is an issue with the bottom fan on a twin fan unit and the fault lies either with the motor in the fan or the circuit board that it is connected to. Only the top fan will spin and it will fault constantly to the point where it won’t stay on long enough to warm the water. This can be checked by reversing the connections for top and bottom motors on the circuit board and seeing if it’s the motor or the board that is faulty. I recommend calling out a Samsung engineer for this one.