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17. Outdoor unit control
17.1 Compressor startup control
O
On startup, inverter compressor will keep for 3 min at 50rps(Tao≥0
C) or 60rps(Tao ＜ 0 ℃ ), then if Tdi SH is still less
than 25 ℃ , compressor will increase frequency up to 100rps. If startup is for 15min or TdiSH is more than 25 ℃ , quit
startup and enter normal operation. In startup operation, the limitation frequency operation will be in priority, such as
high pressure too high, discharging temp. too high, suction pressure too low, overcurrent.
After entering normal operation, when inverter compressor frequency arrives 100rps, fixed frequency compressor
starts up, but if inverter compressor frequency is down to below 30rps, fixed frequency compressor is OFF.
17.2 Compressor operation control
It will be controlled by the target pressure.
In heating and main heating mode, the target high pressure:
When Tao>1 ℃ , target high pressure is 28kg; When Tao<=-6 ℃ , target high pressure is 24kg, Intermediate temperature
is linear
In cooling and main cooling mode, the target low pressure:
Tao≥12 ℃时， target pressure Ps=7.5kg (ET=2 ℃ ) ， Tao ＜ 12 ℃时： ET ＝ 2 ‐ (12-Tao)/2 ℃
17.3 Fan motor control
a. In cooling mode
Startup procedure: When compressor starts up, outdoor motor will not run right now, when high pressure reaches
2.4MPa, outdoor motor begins to run.
In operation, the motor will be controlled by high pressure. When high pressure reaches 2.4MPa, outdoor motor will
run at class-1 speed; if pressure is more than 1.9MPa and less than 2.4MPa, outdoor motor will be in gap control state,
when Pd reached 1.9MPa, the fans stop, when Pd rose 2.4Mpa ， fan motor run at class-1 speed ； if pressure is over
2.4MPa, the speed of fan motor rises 1 class ； When fan motor speed is between class 2 and class 15, the speed will
be according to the target Pd = 2.0MP to fuzzy control. When Pd ＞ 2.1MPa, the fan motor speed rise up class 1. When
Pd≤1.9MPa, the fan motor speed drop class 1. When Pd ＜ 1.8MPa, the fan motor stops.
b. In heating mode
Motor control in startup procedure: Pd
highest. When Tao≥15 ℃、 the speed of fan motor is class 10 。 When defrosting is over, after 4-way valve opens, fan
motor starts up.
In operation, the motor will be controlled by high pressure. Pd
motor speed. 1 minute later, if Pd>=(set pressure +0.50MPa), outdoor motor stops; when Pd
Tao ＜ 15 ℃时、 the speed of outdoor fan motor is highest ， Tao≥15 ℃时、 the speed of fan motor is class 10 。
In defrosting, outdoor motor will stop. After the defrosting is over, 4-way valve opens, outdoor motor will start up at
heating mode.
c. In main cooling mode
Startup procedure: When compressor starts up, outdoor motor will not run right now, when high pressure reaches
3.0MPa, outdoor motor begins to run.
In operation, the motor will be controlled by high pressure. When high pressure reaches 3.0MPa, outdoor motor will
run at class-1 speed; if pressure is more than 2.2MPa and less than 3.0MPa, outdoor motor will be in gap control
state,when Pd reaches2.2MPa ， fan motor stop ， when Pd reaches 3.0MPa ， fan motor run at class-1 speed ； if
pressure is over 3.0MPa, the fan motor speed rise up class 1 ； When fan motor speed is between class 2 and class 15,
the speed will be according to the target Pd = 2.8MP to fuzzy control. When Pd ＞ 2.8MPa, the fan motor speed rise up
class 1. When Pd≤2.2MPa, the fan motor speed drop class 1. When Pd ＜ 2.1MPa, the fan motor stops.
17.4 Defrosting control
When one of the running outdoors reaches the defrosting condition, it will send defrosting signal to the master unit.
After the master unit receives defrosting signal, it will send defrosting signal to the running outdoor. Then the slave
outdoor will begin defrosting.
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