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3-2. EXPANSION VALVE CONTROL (LEV CONTROL)
Linear expansion valve (LEV) is controlled by “Thermostat ON” commands given from each unit.
Indoor unit status LEV opening
Stop of all indoor unit Opening before stop → 500 pulses in 15 minutes
When outdoor unit is operating,
some indoor units stop and some
operate.
COOL: 5 pulses (full closed)
HEAT: (MXZ-2A/3A30NA/2B): 140 pulses (slightly opened)
: (MXZ-3A30NA-
1
/4A/3B/4B): 100 → 59 pulses
Thermostat OFF in COOL or DRY
mode
When the outdoor unit operates (When the other indoor unit operates): 5 pulses
When outdoor unit stops. (When the other indoor unit stops or thermo OFF):
Maintain LEV opening before stop → 500 pulses in 15 minutes
Thermostat ON in COOL or DRY
mode
• LEV opening for each indoor unit is determined by adding adjustment according to the
number of operating unit and the capacity class to standard opening, based on the
operation frequency:
e.g.) Opening 130 pulses in standard opening 1 → Minimum 80 pulses/Maximum 205
pulses (Capacity code 4 at 1 unit operation) (Capacity code 1 at 3 units operation)
• After starting operation, adjustment according to intake super heat, discharge tempera-
ture is included in standard opening.
1
NOTE: LEV opening in each frequency at DRY operation and COOL operation is the
same. However, velocity and compressor operation frequency controls are differ-
ent. See 3-3. OPERATIONAL FREQUENCY RANGE
(As far as the indoor unit velocity control goes, refer to DRY operation in MICRO-
PROCESSOR CONTROL in indoor unit.)
Thermostat OFF in HEAT mode
• When the outdoor unit operates. (When the other indoor unit operates): 140 pulses
• When the outdoor unit stops. (When the other indoor unit stops or thermo OFF): Main-
tain LEV opening before stop → 500 pulses in 15 minutes “
Thermostat ON in HEAT mode
• LEV opening for each indoor unit is determined by adding adjustment according to the
number of operating unit and the capacity class to standard opening, based on the
operation frequency:
e.g.) Opening 120 pulses in standard opening 1 → Minimum 70 pulses/Maximum 165
pulses (Capacity code 4 at 1 unit operation) (Capacity code 1 at 3 units operation)
• After starting operation, opening becomes the one that adjustment according to dis-
charge temperature was added to basic opening.
1 “
1 LEV opening when the outdoor unit is operating: Upper limit 500 pulses, Lower limit 53 pulses (MXZ-2A/3A30NA/2B)/59
pulses (MXZ-3A30NA-
1
/4A/3B/4B).