54
Fault Handling
7-5. Unit Defrosting
Start pressure and stop pressure:
Different start pressures for defrosting corresponding to ambient temperature changes:
Stop conditions for defrosting:
During the defrosting of any system, if the air exhaust pressure is >2967kPa for 10s, or the defrosting operation period is >
"
Maximum defrosting
operation time
"
, or the high pressure switch trips, or the discharge water temperature
≤
"
Cooling anti-freezing starting temperature (fan coil/plate
type heat exchanger)
"
+2
℃
, the system will switch from defrosting to heating mode. The low pressure switch detection will not be activated within
1 minute after the defrosting is stopped.
If the defrosting is stopped due to high pressure tripping, the high pressure detection will be stopped for 20s.
After the defrosting is stopped, the fan will be activated first, the four-way valve will be turned on 15s later, and the system will switch to heating.
