Mitsubishi Electric MXZ-A14WV Service Manual page 50

11-2.HEAT DEFROSTING CONTROL
(1) Conditions to enter defrosting mode
1. When temperature of defrosting thermistor is -3; or less.
2.When specified non-defrosting time, is counted in the control p.c.board is satisfied.
(Total time of compressor operating)
Going to defrosting mode at both condition of 1 and 2.
(2) Defrosting operation
1. Compressor stops for 50 seconds, Indoor fan is off, Defrosting lamp lights.
2.4-way valve reverses flow, Compressor operates by the frequency in heat defrosting control.
3. After compressor stops for 35 seconds, 4-way valve reverses flow, then defrosting finishes.
(3) Conditions to finish defrosting mode
1. When the defrosting thermistor temperature is 13.2; or more.
2. When it has spent 10 minutes for defrosting.
Defrosting finishes at condition of 1 or 2.
11-3.DISCHARGE TEMPERATURE PROTECTION CONTROL
This protection controls the compressor ON/OFF and operation frequency according to temperature of the discharge
temperature thermistor.
(1) Compressor ON/OFF
When temperature of the discharge temperature thermistor exceeds 116;, the control stops the compressor.
When temperature of the discharge temperature thermistor is 80; or less, the controls starts the compressor.
(2) Compressor operation frequency
When temperature of the discharge temperature thermistor is expected to be higher than 116;, the control decreases 12Hz
from the current frequency.
When temperature of the discharge temperature thermistor is expected to be higher than 111; and less than 116;, the con-
trol decreases 6Hz from the current frequency.
When temperature of the discharge temperature thermistor is expected to be higher than 104; and less than 111;, the con-
trol is set at the current frequency.
11-4.REFRIGERANT RECOVERY CONTROL ON HEATING
<Control status>
The control performs when the all the following status are satisfied;
• When one or more indoor units are operating in HEAT mode. (Excluding thermostat OFF)
• When discharge temperature becomes 107; or more.
• When it passed 60 minutes or more since the operation has started or the last refrigerant recovery has controlled.
<Control details>
LEV opening of indoor unit not operating is controlled to be 80 pulse.
<Control finish status>
The control finishes either as follows. However, the LEV opening is considered to be 59 pulse.
• When it passed 60 seconds since the control has started.
• When the discharge temperature is 90; or less.
11-5.OUTDOOR FAN CONTROL
Fan speed is switched according to the number of operating indoor unit and the compressor frequency.
Fan speed
Down
High
Low
Min. Compressor frequency
<Relation between compressor frequency and fan speed.>
MXZ-A14WV, MXZ-A18WV
Mode
Fan speed
COOL
HEAT
Note
• When the indoor coil thermistor is 57; or more on HEAT operation, fan speed is fixed to Low speed.
Or, the indoor coil thermistor is 45; or less on HEAT operation, fan speed is back to normal.
Up
Max.
Indoor unit operation
1 unit 2 units
Up
60Hz 60Hz
Down 50Hz 50Hz
Up
60Hz 60Hz
Down
50Hz 50Hz
MXZ-A26WV, MXZ-A32WV
Mode
Fan speed
COOL
HEAT
50
Indoor unit operation
1 unit 2 units 3, 4 units
Up
45Hz 50Hz
Down 35Hz 40Hz
Up
50Hz 55Hz
Down
40Hz 45Hz
55Hz
45Hz
60Hz
50Hz