Electric Control Functions Of Au48Nfibia; Capacity Control Of Compressor; Startup Control Of Compressor - Haier H-MRV Series Service Manual

>a__WcU[S^ <[c >a`V[e[a`Wc

8.2 Electric control functions of AU48NFIBIA

1. Capacity control of compressor

Operation mode: entering earlier in prior, cooling and heating can not operate simultaneously.
In cooling, the output frequency of the transducer depends on the indoor capacity request and the
outdoor ambient temperature; in heating, firstly the indoor capacity request and the outdoor ambient
temperature will confirm the base frequency, then the indoor evaporator temperature will adjust the
output frequency of the transducer. The indoor capacity request can be calculated as per the
capacity and the temperature difference between the set temperature and the indoor actual
temperature.
Low frequency protection: When the horse power of all running indoor unit is over 2HP, after the
output frequency stays for 15 minutes at 30Hz, then the output frequency will arise to 40Hz and run
for the time of low_f_prot_t, then the frequency will resume to the target frequency.
High frequency protection: After the output frequency runs for 15 minutes at over 110Hz, the output
frequency will reduce to 100Hz and run for 5 minutes, then it will resume to the target frequency.

2. Startup control of compressor

2.1 Protection at startup
In order to prevent the constant startup of compressor, and keep the pressure balance of the
system, within 3 minutes after compressor shuts off, please do not start up the compressor, 3
minutes later, the compressor can re-start up.
2.2 Soft startup ( 3 minutes)
In order to protect the compressor and the transducer, when startup, the unit will decrease the
startup load, and operate as follow:
Within 3 minutes after the compressor starts up, the unit runs at the fixed low frequency of 50Hz to
prevent the liquid type refrigerant being sucked into the compressor. Open solenoid valve to make it
pass by, and run with low load. 3 minutes later, the unit will run at the target frequency.
2.3 Reducing-pressure startup
In heating, when compressor stops, the refrigerant will remain in the gas-liquid segregator, in order
to prevent the blocked liquid at the next compressor startup, the compressor will make
reducing-pressure startup. After the gas-liquid segregator is dry completely, the compressor will
operate normally.
2.4 Pre-heat startup in heating mode
Because the compressor does not run for long time and the refrigerant does not circle, when
re-startup, it will cause refrigerant foam resulting in the compressor lack of oil, so the pre-heat can
ensure that low pressure will not reduce too much.
3. Outdoor EEV control
If reset when being electrified on, EEV is close totally, -500 pulses.
When in shutoff, or in cooling, in defrosting, EEV is open totally, 480 pulses.
When in oil return operation in heating mode, the open angle of EEV is the base angle of 6HP unit.
In normal heating mode, EEV will confirm a base angle as per the indoor capacity request, then
according to the overheat value, the system can micro-adjust the angle.
In heating the adjustment of EEV:
3.1 The min open angle is no less than 80, and the max open angle is no more than 350
3.2 After the soft startup is over, EEV will confirm the target overheat value due to the outdoor
ambient temperature
-100-