Abnormality / Protection
control
Primary location to verify
Indoor/Outdoor capacity
unmatched
• Indoor/outdoor connection wire
• Indoor/outdoor PCB
• Specification and combination table in
Catalogue
Outdoor compressor
temperature sensor
abnormality
• Compressor temperature sensor
(defective or disconnected)
Indoor refrigerant liquid
temperature
sensor abnormality
• Refrigerant liquid temperature sensor
(defective or disconnected)
Compressor low pressure
abnormality
• Outdoor pipe temperature sensor
• Clogged expansion valve or strainer
• Insufficient refrigerant
• Outdoor PCB
• Compressor
Water flow switch abnormality
Refrigerant high pressure
abnormality
• Outdoor high pressure sensor
(defective or disconnected)
Back-up heater OLP
abnormality
• Back-up heater OLP
(Disconnection or activated)
Indoor - remote control
communication
abnormality
• Indoor - control panel
(defective or disconnected)
Indoor / outdoor abnormal
Communication
> 1 min after starting operation
• Internal / external cable connections
• Indoor / Outdoor PCB
Tank heater OLP abnormality
• Domestic hot water cylinder high limit
stat or temperature thermostat
disconnection or activated.
• Check thermostat is set to maximum
temperature on the cylinder.
•Test for continuity between pins13 and
14 at the heat pump.
Indoor/Outdoor wrong
connection
• Indoor/Outdoor supply voltage
Outdoor high pressure
overload
protection
• Outdoor high pressure sensor
• Water pump or water leakage
• Clogged expansion valve or strainer
• Excess refrigerant
• Outdoor PCB
Indoor heat exchanger freeze
prevention
• Indoor heat exchanger
• Refrigerant shortage