Electra WNG 50 DCI Service Manual page 67

12.5.3 Compressor Speed Control
12.5.3.1 Compressor Min On/Off time
Compressor minimum OFF time is (MinOFFTime) 3 minutes except during Deicing protection.
Compressor minimum ON time is (MinOnTime) 3 minutes, minimum ON time is ignored during
protections, and when unit is turned to STBY.
12.5.3.2 Compressor Speed calculation
During normal operation (excluding protections), the compressor speed is limited by the
minimum speeds:
Min Speed Max Speed
Cool Cool
15 75
12.5.3.3 Indoor Units NLOAD calculation
The NLOAD setting is done by the indoor unit controller, based on a PI control scheme.
The actual NLOAD to be sent to the outdoor unit controller is based on the preliminary LOAD
calculation, the indoor fan speed, and the power shedding function.
NLOAD limits as a function of indoor fan speed:
Indoor Fan Speed
Low
Medium
High
Turbo
Auto
NLOAD limits as a function of power shedding:
Mode
Cool
Heat
12.5.3.4 Outdoor Unit NLOAD calculation
ODU NLOAD is the weighted average of IDU NLOAD:
IDU NLOAD
ODU =
ODUCode
ODU codeH is defined as following:
The code for heat mode is related also to outdoor temperature and so in low heating conditions
the compressor speed will be higher.
Compressor speed will be set between the minimum speed and the max speed according to
the ODU NLOAD.
ODU codeC is defined as following (EEPROM values):
Unit type
Single (Default)
Service Manual - WNG 50_60_80 DCI
Min Speed Max Speed
Heat
15
Maximum NLOAD Cooling
Max NLOADIF1C
Max NLOADIF2C
Max NLOADIF3C
Max NLOADIF4C
Max NLOADIF5C
Power Shedding OFF
No limit
No limit
Code
ODU codeC
Cool
3
Revision Y05-02
CONTENT
Heat
95
Maximum NLOAD Heating
127
127
127
127
127
Power Shedding ON
Nominal Cooling
Nominal Heating
CONTROL SYSTEM
12-11