Samsung AM072BXV Series Service Manual page 238

Piping Diagram
7-3 Functions (cont.)
7-3-2 Control (cont.)
7-3-2-2 Start-up modes (cont.)
Safety Start – Cold Start
▪ Purpose
Protect the system and compressors by preventing poor lubrication due to liquid compression or oil foaming.
▪ Concept
- A low start-up frequency is used to protect the compressors from liquid compression as well as poor lubrication due to oil foaming.
- After the Cold Start process, Cold Operation mode is on for a maximum of 60 minutes to decrease the compressor frequency
increase speed until DSH is secured. This prevents liquid compression.
▪ Control specifications in detail
- Condition(s) required to enter Cold Start mode : [ (A or B) & C & D ]
A. Max (Ttop, Tdis) – Tair < 15 K
B. Max (Ttop, Tdis) < 30℃
C. Less than 12 hours after the power supply
D. Cooling : Ambient temp < 30℃ , Heating : Ambient temp < 20℃
- In Cold Start mode, the target SH of 6 K is regulated and compressors are controlled as shown below.
(See the charts below for conditions required to complete specific steps)
If one compressor is ON
In Cold Operation mode, the compressor frequency increase speed is restricted to 1Hz per 60 sec.
Condition(s) required to close Cold Operation mode: [ A or B ]
A. A maximum of 60 min has elapsed
B. DSH > 15 K
Samsung Electronics
If two compressors are ON
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