High Pressure Over High Control; Low Pressure Over Low Control - Haier HU062WAMNA Service Manual

18.4 High pressure over high control

To prevent abnormal rise of high pressure and cause system protection stop in cooling or heating.
Start condition: Cooling/Heating mode: Pd_t ≥(58+ HPRmin)°C;
Control compressor speed:
When Pd_t≥62+ HPRmin, compressor stops;
When 60+HPRmin≤Pd_t ＜ 62+ HPRmin, compressor frequency reduced;
When 58+HPRmin≤Pd_t ＜ 62+ HPRmin, compressor frequency forbided to increase;
When Pd_t ＞ 58HPRmin, compressor recovers the frequency rise
Note: 1.Compressor stop will cause high pressure over high failure
2.HPRmin=min(HPR1,HPR2), HPR1 is the high pressure modification value at different low pressure saturation
temperatures
3.In order to keep the normal cooling/heating operation, low pressure protection conrtol is needed through low
pressure sensor.

18.5 Low pressure over low control

Cooling
① Starting condition
Ps ＜ 0.6MPa
② Controls
≤0.6MPa
＞ 0.7Mpa*2
Start again after 5 minutes
＜ 0.6MPa *1
*1: Protection will stop when last for 5 minutes
*2: Minimum power on time for SV1 is 2 minutes or Ps ＞ 0.75MPa in 2 minutes
*3: Compressor frequency control:
When Ps_t ＜ -6°C, compressor stops;
When -6≤Ps_t ＜ -2, compressor frequency reduced;
When -2≤Ps_t ＜ 0, compressor frequency forbided to increase;
When Ps_t ＞ 0, compressor recovers the frequency rise
*4: Ps ＜ 0.56Mpa and last for 1 minute, or Ps_t ＜ -7°C and last for 10 seconds, error stops and system report
E39 failure
③ Quit condition
Ps≥0.75MPa
SV1:ON
Protection stopped
Only one time the error will stop
Frequency control (*3)
＜ 0.56MPa *1,
last for 1 minute *4
Error stop
118