Filter
Top Products
64
6-2. Outdoor Unit
6-2-1. Operation Start/Operation End
The compressor, solenoid valve, pulse motor valve (PMV), outdoor fan, etc. are controlled by a command from
the indoor controller. The follower outdoor unit starts/stops by a command from the header outdoor unit.
PMV opening
45
90
500
550
1000
Min. Med. Max.
PMV 1
PMV 2
No.
1
2
Item
Pulse Motor Valve
(PMV) control
Outdoor fan control
Operation explanation and applied data, etc.
(1) PMV control (using two PMV, 1 and 2)
• Each PMV is controlled between 90 to 1000 pulses
during operation.
• In cooling operation, PMV opening is dependent upon
detected readings from the TL sensor and Pd pres-
sure sensor (sub-cool control).
• In heating operation, PMV opening is dependent upon
detected readings from the TS and TD sensors and
the Ps pressure sensor (super-heat control).
• Each PMV will be fully closed when the system is in
‘Standby’ or ‘No demand’ modes and when a malfunc-
tion in the system has occurred.
(2) PMV3 control
1) PMV3 (Pulse Motor Valve 3) is controlled between 0
to 500 pulses during mainly cooling, part heating or
mainly heating, part cooling operation.
2) PMV3 opening is controlled according to the demand
capacity difference (HP) between the cooling
capacity and the total heating capacity.
3) The PMV will be fully closed when the system is in
‘Standby’ or ‘No demand’ modes and when a mal-
function in the system has occurred.
(1) Fan control in all cooling operation
1) The outdoor fan speed/mode is determined by the
detected Pd pressure value.
2) When cooling operation has started, the outdoor fan
speed of the master unit is controlled using the
detected Pd pressure value.
(2) Fan control in all heating operation
1) The outdoor fan speed/mode is determined by the
detected TE sensor value.
2) If a TE value > 25°C has been continuously detected
for 5 minutes, the operation may stop.
3) After start up, this control is not available during the
specified time after a defrost operation.
4) This operation may start and stop repeatedly when
the system is undercharged.
(3) Fan control for mainly cooling, part heating operation
The outdoor fan speed (mode) is controlled according to
the target of the Pd (Discharge pressure).
Remarks
• During heating operation,
PMV2 is 0 pulses and
PMV may be controlled
with only PMV 1, with a
minimum of 45 pulses.
When TE temp. (ambient
temperature) exceeds 25°C,
Heating operation stops.
• The maximum fan speed
differs depending on the
outdoor HP.