4. Troubleshooting
Protection control function
SMGB0082 rev.1 - 07/2015
116
4.5
Protection control function
This Chiller unit is provided with protection control functions to release abnormal statuses before reaching alarm because
of abnormality occurrence.
Name of
protection control
(Compressor
frequency control)
Conditions for
Operation
Description of Control
Release conditions
Display
LCD
Segment
Overcurrent
protection
(Unit current)
I1 > Setting value×0.97
I1 > Setting value
* I1: Unit current
Load up prohibition
Forced load down
I1 < Setting value×0.95
I1 < Setting value×0.98
Current
limited
Differential
Pressure Protection
Pd-Ps
≤
0.3MPa
Pd-Ps
≤
0.25MPa
* Pd: High pressure
Ps: Low pressure
Load down
prohibition
Forced load up
60 seconds passed and
Pd-Ps > 0.3MPa
Ps > 0.3MPa
Differential
pressure
limited
Outlet Water
Temperature
Decrease
Prevention
Twp
≤
2ºC
Twp
≤
1.5ºC
* Twp: Outlet water
temperature (Protection)
Load up prohibition
Forced load down
30 seconds passed and
Twp > 2ºC
Twp > 2ºC
Outlet water
temperature
limited
Discharge Pressure
Over-increase
Prevention
Pd
≥
1.84MPa
Pd
≥
1.86MPa
*Pd: High pressure
Load up prohibition
Forced load down
10 minutes have passed
or
Pd
≤
1.76MPa
Pd
≤
1.84MPa → To
Control
High
pressure
over-increase
limited
Suction Pressure
Decrease
Prevention
Air-cooled systems
(Cooling only)
Ps < 0.17MPa
Ps < 0.13MPa
* Ps: Low pressure
Load up prohibition
Forced load down
Air-cooled systems (Cooling
only)
Ps < 0.19MPa
Ps < 0.15MPa
Low pressure
decrease
limited
Cooler inlet
refrigerant
temperature
decrease
prevention (at
Cooling operation)
Tr < -4ºC
* Tr: Cooler inlet
refrigerant temperature
Load up prohibition
60 seconds passed
Cooler
refrigerant
temperature
limited
Frost formation
limitation
Ps ≤ 0.05MPa AND
100% pressure switch for
detection ON
Ps
≤
0.05MPa AND
100% pressure switch for
detection OFF
Forced load down
Load up prohibition
5 minutes passed OR Ps ≥
0.1MPa
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