Other cautions

1.Cooling operation in low ambient temperatures

1)The indoor unit freeze prevention control system (TC sensor) may decrease the command frequency to the outdoor unit when low coil temperatures are detected.

2)The cooling capacity control may decrease the command frequency to the outdoor unit when low ambient temperature is detected.

3)When the discharge temperature sensor value reaches 60°C or below, the frequency may be increased above the required demand from the indoor unit.

2.PMV (Pulse Motor Valve) for outdoor unit

1)When the system power is turned on an audible “clicking” sound is omitted due to the PMV initialising, this is a normal condition. When the outdoor unit is situated near other sources of noise, this sound may not be noticeable.

2)Do not remove the driving part (head) of the PMV during operation as it may cause the PMV to malfunction.

3)When transporting or replacing the outdoor unit, never keep the driving part (head) removed from the PMV body as the valve will be closed and may result in damage or failure due to sealed liquid compression.

4)When refitting the driving part (head) to the body of the PMV, apply pressure until a “click” sound can be heard, complete the process by resetting the power to the system.

Release control list

Release item

High pressure release

Operation

SV2 ON, SV41, SV42 ON

PMV3=45 pulses (All heating operation), 60 pulses (All cooling operation) Operation frequency limit

Low pressure release

SV2 ON, SV41, SV42 ON, Operation frequency limit

Discharge temp. release

SV6 ON, Operation frequency limit

Current release

Operation frequency limit

Heat sink release

Outdoor fan speed up, Operation frequency limit

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Toshiba MMU-AP0091H service manual Other cautions, Release control list, Cooling operation in low ambient temperatures