Airwell YBZE218-324-430, Service Manual

Page: 38 / 68

CONTROL SYSTEM
12-2 Service Manual
– YBZE DCI 1-A.1 GB
12.1.2 Compressor Frequency Control
12.1.2.1 Compressor frequency setting
The Load calculation is done by each indoor unit controller, based on a PI control scheme which
is based on the difference between SPT and RAT.
ODU controller will decide the compressor frequency based on the total load from all the indoors.
Compressor frequency will be limited within following ranges:
Mode
Minimum Frequency (MinFreq)
Maximum Frequency (MaxFreq) *
YBZE218 YBZE324 YBZE430 YBZE218 YBZE324 YBZE430
Cooling 15 15 15 110 110 110
Heating 15 15 15 110 110 110
* Maximum frequency is also decided by different indoor combinations.
12.1.2.2 Frequency Changes Control
Frequency change rate is 1 Hz/sec.
12.1.2.3 Compressor Starting Control
30Hz
40Hz
50Hz
60Hz
70Hz
80Hz
90Hz
1min 2min 2min
12.1.2.4 Minimum On and Off Time
Prohibit turning ON the compressor for 3 minutes after turning it off. (Except during deicing
protection)
Prohibit turning OFF the compressor for 7 minutes after turning it on (except protections required
immediate compressor stop)
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