Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 835

2000 air conditioning & heat pump machinery handbook

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Cooling operation control at lower outdoor air temperature (down to –5˚C)

(a) This control starts 1 minute after starting compressor during cooling or dehumidifying operation, controls the outdoor fan at the

outdoor temperature (Tho-A) being below 22˚C and enables the cooling operation.

Outdoor fan control effective

(b) Outdoor fan control

Outdoor air temperature (˚C)

Outdoor fan tap

3 speed 2 speed 1 speed

(c) In cases of 224 and 280 only, the low outdoor air cooling control is releases temporarily when the number of operating compres-

sors is changed (1 unit → 2 unit) and the outdoor fan is operated in the Hi mode. The low outdoor air temperature cooling control

becomes effective 2 minutes later.

(12) Snow protection fan control

If J6 on the outdoor unit PCB is opened, the outdoor fans on the units which have been stopped with the total or error stop are

operated in the Hi mode once at every 10-minute while the outdoor temperature is lower than 3˚C.

(External air temperature)

(13) Forced heating/cooling operation

With this control, SW3-7 on the outdoor unit PCB is turned on and CnG (equipped with short circuit pin) is shorted or opened so

as to forcibly determine whether the indoor unit is operated for cooling or heating. If any operation mode other than the forcible

mode is commanded from the indoor unit, the mode unmatch message is displayed on the remote controller or others and the

operation enters in the blowing mode.

Note (1) SW-7 is at OFF and CnG is open at the shipping from factory.

Outdoor air temperature (˚C)

For 140 : OFF, 1 ~ 2 speed control ranges

For 224, 280 : OFF, 1 ~ 3 speed control ranges

For 140 : 1 ~ 3 speed control ranges

For 224, 280 : 1 ~ 4 speed control ranges

224,280 models

4 speed 3 speed 2 speed 1 speed

Normal operation

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