Characteristics Of Heat Mode Operation; Self Diagnosis Function - Mitsubishi Daiya SKM22ZD-S User Manual

Characteristics of HEAT mode operation

Mechanism and capacity of HEAT mode operation
Mechanism
• The unit draws in heat from the cold outside air, transfers it indoors and heats the room. The heating capacity of the heat pump mechanism decreases
when the outside air temperature gets colder.
• The hot air circulation system takes a while before warming up the room temperature.
• If the outside temperature becomes extremely low, it would be better to use an additional source of heating.
• If heating operation is performed when the outside temperature is high, room temperature may become higher than the set temperature.
Defrosting
If the outside temperature becomes low and humidity is high, the heat exchanger in the outdoor unit may frost over, which prevents efficient heating.
If this happens, the automatic defroster is activated and during defrosting the heating operation stops for 5 to 10 minutes.
• Both indoor and outdoor fans stop and the RUN light (green) blinks slowly (1.5 sec. ON, 0.5 sec. OFF) during defrosting.
• The outdoor unit may give off some steam during defrosting. This is to help the defrosting process and is not a defect.
• The HEAT operation resumes as soon as defrosting has been completed.

Self diagnosis function

We are constantly trying to do better service to our customers by installing such judges that show abnormality of each function as follows:
TIMER lamp ON
RUN lamp keeps flashing
RUN lamp ON
RUN lamp 2 time flash
RUN lamp
Description of trouble
Heat exchanger sensor (1) error
1 time flash
Room temperature sensor error
2 time flash
5 time flash Heat exchanger sensor (2) error
Indoor fan motor error
6 time flash
Closed service valve
7 time flash
Heat exchanger sensor (1) error
TIMER lamp
Outdoor temperature sensor error
1 time flash
Outdoor heat exchanger fluid pipe
2 time flash
sensor error
4 time flash
Discharge pipe sensor error
5 time flash Suction pipe sensor error
6 time flash Power transistor sensor error
1 time flash Current cut
Trouble of outdoor unit
2 time flash
3 time flash Over current
Over heat of power transistor
4 time flash
Over heat of compressor
5 time flash
6 time flash Error of signal transmission
Rotor lock
2 time flash
– 20 –
Cause
• Broken heat exchanger sensor (1) wire, poorconnector
connection
• Disconnected sensor
• Broken room temperature sensor wire, poor connector connection
• Broken heat exchanger sensor (2) wire, poor connector
connection
• Disconnected sensor
• Defective fan motor, poor connector connection
• Closed service valve
• Disconnected sensor
• Broken outdoor sensor wire, poor connector connection
• Broken heat exchanger fluid pipe sensor wire, poor connector
connection
• Broken discharge pipe sensor wire, poor connector connection
• Broken suction pipe sensor wire, poor connector connection
• Broken power transistor sensor wire, poor connector connection
• Compressor locking, open phase on compressor output,
shortcircuit on power transformer, closed control valve
• Broken power transformer, broken compressor wire
• Broken discharge pipe sensor wire, poor connector connection
• Compressor blockage
• Overload operation, overcharge
• Cooling problem
• Gas shortage, defective discharge pipe sensor, closed control
valve
• Defective power supply, Broken signal wire, defective in/outdoor
unit boards
• Defective compressor
• Open phase on compressor
• Defective outdoor unit boards