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The following symptoms do not indicate malfunction.
Symptom Cause
Water flowing sound during operation. • Refrigerant flow inside the unit.
Operation is delayed a few minutes 
after restarting.
• The delay is a protection for the compressor.
Outdoor unit emits water/steam. • Condensation or evaporation occurring in the pipes.
Steam comes out of the outdoor unit in 
the heating mode.
• It is caused by defrost operation in the heat exchanger.
Outdoor unit does not operate. • It is caused by the protection control of the system when outdoor temperature is 
out of the operating range.
System operation switches off. • It is caused by the protection control of the system. When the water inlet 
temperature is lower than 10 °C, the compressor stops and the backup heater 
power turns on.
System is hard to heat up. • When the panel and the floor are heated simultaneously, warm water temperature 
may decrease, which may reduce the heating ability of the system.
• When the outdoor air temperature is low, the system may need longer time to heat 
up.
• Discharge outlet or intake inlet in the outdoor unit is blocked by some obstacle, 
such as a pile of snow.
• When the preset water outlet temperature is low, the system may need longer time 
to heat up.
System does not heat up instantly. • System will take some time to heat up the water if it starts to operate at cold water 
temperature.
Backup heater is automatically turned 
ON when it is disabled.
• It is caused by the protection control of the indoor unit heat exchanger.
Operation starts automatically when the 
timer is not set.
• Sterilisation timer has been set.
Display power consumption remains 
as previous value.
• Memory is saved on hourly basis. If a power failure occurs, the data kept from last 
hour will be displayed.
• Total power consumption has reached 999 days. press 
 to reset the counter.
HEAT indicator blinks on the display. • System is performing deice operation.
Loud refrigerant noise continue for a 
few minutes.
• It is caused by protection control during deice operation at outdoor ambient 
temperature lower than -10°C.
*
1 
Cool mode is unavailable. • System has locked to operate in HEAT mode only.
Check the following before calling for servicing.
Symptom Check
Operation in HEAT/ 
*
1 
COOL mode is 
not working efficiently.
• Set the temperature correctly.
• Close the panel heater/cooler valve.
• Clear any obstruction in the air inlet and air outlet vents of the outdoor unit.
Noisy during operation. • Outdoor unit or indoor unit has been installed at an incline.
• Close the cover properly.
System does not work. • Circuit breaker has tripped/activated.
Operation LED is not lit or nothing is 
displayed on the control panel.
• Check that the power supply is working correctly, or that a power failure has not 
occurred.
Troubleshooting
Force Heater Mode Button
• If a malfunction occurs in the system, the backup heater may be used to heat up the water. 
Press   to switch on the backup heater.
• Press 
 to switch off the backup heater.
• In the Force Heater mode, no other operation can be used.
*
1
  The system is locked to operate without COOL mode. It can be unlocked only by authorized installers or our authorized service partners.
*
2
  Only displayed when COOL mode is unlocked (Means when COOL mode is available).
How to use / Cleaning instructions / Troubleshooting