Toyotomi Kuro MTN A228DV Service Manual page 7

Outdoor unit
Power relay control
The unit has 3 mins delay between continuously ON/OFF operations.
Low noise air flow system
Bird tail propeller fan makes the outdoor unit run more quietly.
Hydrophilic aluminum fin
The hydrophilic fin can improve the heating efficiency at operation mode.
4 way valve control
It is only operated in the heating operation mode except defrosting operation.
Anti-rust cabinet
Made from electrolytic zinc steel sheet and anti-rust coated components.
Valve protection cover
It protects the valves and prevents water from dripping.
Discharge pipe temperature protect
Driving heating at -15℃
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