4 Troubleshooting
Protection control function
SMGB0120 rev.0 - 11/2017
92
4.4
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
Cooling
Pd
≥
1.41MPa
Pd
≥
1.44MPa
*Pd: high pressure
Load up prohibition
Forced load down
Cooling
10 minutes have
passed or
Pd
≤
1.39MPa
Pd
≤
1.41MPa →
To Control
High
pressure
over-increase
limited
Cooling/Heating
Pd
≥
1.84MPa
Pd
≥
1.87MPa
*Pd: high pressure
Load up prohibition
Forced load down
Cooling/Heating
10 minutes have
passed or
Pd
≤
1.82MPa
Pd
≤
1.84MPa →
To Control
High
pressure
over-increase
limited
Suction pressure
decrease
prevention
Water-cooled systems
(Cooling only)
Ps < 0.18MPa
Ps < 0.14MPa
* Ps: low pressure
Load up prohibition
Forced load down
Water-cooled systems
(Cooling only)
Ps < 0.20MPa
Ps < 0.16MPa
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