27
ERROR 
CODE
MALFUNCTION 
OR PROTECTION
FAILURE CAUSE 
AND CORRECTIVE ACTION
1.The same reason to P1.
2. Power supply voltage of the unit is low, increase the power 
voltage to the required range.
Compressor overcurrent 
protection.
Heating mode, DHW mode: 
1. The water flow is low; water temp is high, whether there is 
air in the water system. Release the air. 
2. Water pressure is lower than 0.1Mpa, charge the water to let 
the pressure in the range of 0.15~0.2Mpa.
3. Over charge the refrigerant volume. Recharge the refrigerant 
in right volume. 
4. Electrical expansion valve locked or winding connector is 
loosen. Tap-tap the valve body and plug in/ plug off the 
connector for several times to make sure the valve is working 
correctly. And install the winding in the right location DHW 
mode: Water tank heat exchanger is smaller .Cooling mode: 
1.Heat exchanger cover is not removed. Remove it. 
2. Heat exchanger is dirty or something is block on the surface. 
Clean the heat exchanger or remove the obstruction.
High pressure protection
1.The same reason to P1. 
2.TW_out temp.sensor is loosen Reconnect it.. 
3. T1 temp.sensor is loosen. Reconnect it. 
4. T5 temp.sensor is loosen. Reconnect it.
High discharge temperature 
protection.
1. Power supply voltage of the unit is low, increase the power 
voltage to the required range.
2. The space between the units is too narrow for heat 
exchange. Increase the space between the units. 
3. Heat exchanger is dirty or something is block on the surface. 
Clean the heat exchanger or remove the obstruction.
4. Fan is not running. Fan motor or fan is broken, Change a 
new fan or fan motor.
5. Over charge the refrigerant volume. Recharge the refrigerant 
in right volume. 
6. Water flow rate is low, there is air in system, or pump head 
is not enough. Release the air and reselect the pump. 
7. Water outlet temp.sensor is loosen or broken, reconnect it or 
change a new one. 
9.Module wires or screws are loosen. Reconnect wires and 
screws. The thermal conductive adhesive is dry or drop.Add 
some thermal conductive adhesive. 
10.The wire connection is loosen or drop. Reconnect the wire. 
11. Inverter module board is defective, replace a new one. 
12. If already confirm the control system has no problem, then 
compressor is defective, replace a new compressor.
13.The shut valves are closed,open the shut valves.
Module protection