Start, Stop And Capacity Control; Cooling Capacity Control06 - RFC SL Series Technical Manual

3. Start, stop and cooling capacity control
3.1 Cooling capacity control
3.1.1 SL100~420 compressors adopt three-stage energy regulation, the minimum load is 50%,
and its control solenoid valve logic is as follows:
compressor load
Minimum load (start)
70% load
100% load
3.1.2 SL520~640 compressors use four-stage energy regulation, the minimum load is 25%,
and the minimum load is only used for startup. The logic of its control solenoid valve is as
follows:
compressor load
Minimum load (start)
50% load
75% load
100% load
Notice：
1) Careful and extensive testing is strongly recommended for less than 50% load conditions.
Continuous operation below 50% load should be avoided unless adequate measures are
taken to prevent:
Poor oil return due to low return air flow rate.
Excessive exhaust temperature due to poor motor cooling and reduced efficiency
(especially at high pressure ratios)
Motor overheating due to low power factor at low loads (especially when supply voltage
exceeds rated voltage)
2) Since the cooling of the motor may not be guaranteed at the 25% minimum cooling capacity
level, the minimum cooling capacity level can only be used for the start and stop phases of the
compressor.
50% solenoid valve
power ups
power outage
power outage
Table 2-2
25% solenoid valve
power ups
power outage
power outage
power outage
75% solenoid valve
power outage
power ups
power outage
50% solenoid valve
power outage
power ups
power outage
power outage
75% solenoid valve
power outage
power outage
power ups
power outage