Mitsubishi Heavy Industries SRF25ZMXA-S Technical Manual & Parts List Download

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'14 • SRF-T-163

(n) Serial signal transmission error protection

(i) Purpose:

Prevents malfunction resulting from error on the indoor

↔

outdoor signals.

(ii) Detail of operation:

If the compressor is operating and a serial signal cannot be received from the indoor control

with outdoor control having serial signals continues for minute and seconds, the compres-
sor is stopped.

After the compressor has been stopped, it will be restarted after the compressor start delay if a se-
rial signal can be received again from the indoor control.

(o) Rotor lock

If the motor for the compressor does not turn after it has been started, it is determined that a compressor lock has occurred
and the compressor is stopped.

(p) Outdoor fan motor protection

If the outdoor fan motor has operated at min

or under for more than 0 seconds, the compressor and fan motor are stopped.

(k) Current cut

(i) Purpose:

Inverter is protected from overcurrent.

(ii) Detail of operation:

Output current from the inverter is monitored with a shunt resistor and, if the current exceeds

the setting value, the compressor is stopped immediately. Operation starts again after a delay
time of minutes.

(I)

Outdoor unit failure

This is a function for determining when there is trouble with the outdoor unit during air conditioning.

The compressor is stopped if any one of the following in item (i), (ii) is satisfied. Once the unit is stopped by this function, it is not

restarted.
(i) When the input current is measured at A or less for continuous minutes or more.
(ii) If the outdoor unit sends a 0 rps signal to the indoor unit times or more within 0 minutes of the power being turned on.

(m) Indoor fan motor protection

When the air conditioner is operating and the indoor fan motor is turned ON, if the indoor fan motor has operated at 0
min

or under for more than 30 seconds, the unit enters first in the stop mode and then stops the entire system.

(q) Outdoor fan control at low outdoor temperature

(i) Cooling

1) Operating conditions:

When the outdoor air temperature (TH) is ºC or lower continues for 0 seconds

while the compressor command speed is other than 0 rps.

2) Detail of operation:

After the outdoor fan operates at A speed for 0 seconds; the corresponding outdoor heat

exchanger temperature shall implement the following controls.

a) Outdoor heat exchanger temperature =< ºC

After the outdoor fan speed drops (down) to speed for 0 seconds; if the outdoor heat exchanger tempera-
ture is lower than ºC

, gradually reduce the outdoor fan speed by 1 speed. (Lower limit 1st speed)

b) ºC < Outdoor heat exchanger temperature =< ºC

After the outdoor fan speed maintains at A speed for 0 seconds; if the outdoor heat exchanger temperature

is ºC-ºC, maintain outdoor fan speed.

c) Outdoor heat exchanger tempeature > ºC

After the outdoor fan speed rises (up) to speed for 0 seconds; if the outdoor heat exchanger temperature is
higher than ºC, gradually increase outdoor fan speed by speed. (Upper limit rd speed)

3) Reset conditions:

When either of the following conditions is satisfied

a) The outdoor air temperature (TH) is ºC or higher.
b) The compressor command speed is 0 rps.

Outdoor temperature > 10˚C

Outdoor temperature <= 10˚C

nd speed

Outdoor fan

st speed

Value of A