Service manual

13-3
CONTROL SYSTEM > GC 18/GC 21
SM HADDCI 1-A.2 GB
13.1.8 Heating Element Control
Heating element can be started if LOAD > 0.8 * MaximumNLOAD AND Indoor Coil temperature <
45.
The heating element will be stopped when LOAD < 0.5 * MaximumNLOAD OR if Indoor Coil
temperature > 50.
13.1.9 Outdoor Fan Control
7 outdoor fan speeds are determined for each model. 3 speeds for cool and dry modes, and 3 speeds for heat
mode, and a very low speed.
Outdoor fan speed is a function of compressor frequency and outdoor air temperature (OAT).
4 routines for fan control are determined. The control routine selection depends on operation mode, compressor
speed, outdoor air temperature (OAT) and heat sink temperature (HST).
Routine Conditions
A
Heating with OAT < 15°C or
Cooling with OAT > 20°C, or
Faulty OAT
B Cooling with 20°C > OAT > 7°C
C Cooling with 7°C > OAT
D Heating with OAT > 15°C
Compressor
Target Frequency
OFAN Speed
Normal cases
State A at cool / Heat
State B
at cool
State C
at cool
OAT>15
o
C
at heat
Freq=0
OFF OFF OFF OFF
10 ≤ Freq < OFLowFreq Low Low Low Low
OFLowFreq ≤ Freq< OFMedFreq High Low Low Low
OFMedFreq≤ Freq High Low Low High
In cooling mode, the extra rule is as the below;
When compressor is switched to OFF and the heat sink temperature is above 55 degrees, the outdoor fan will
remain ON in low speed for up to 3 minutes.
13.1.10 EEV (electronic Expansion valve) Control
EEV opening is defined as EEV = EEV
OL
+ EEV
CV
EEV
OL
is the initial EEV opening as a function of the compressor frequency, operation mode, unit
model and capacity.
EEV
CV
is a correction value for the EEV opening that is based on the compressor temperature.
During the first 5 minutes of compressor operation EEV
CV
= 0.
Once the first 5 minutes are over, the correction value is calculated as follow: EEV
CV
(n) = EEV
CV
(n-1)
+ EEV
CTT
EEV
CTT
is the correction based on the compressor temperature. A target compressor temperature is
set depending on frequency and outdoor air temperature, and the actual compressor temperature is
compared to the target temperature to set the required correction to the EEV opening.
Change To Higher
OFAN Cool state (*1)
45
50
HST
Change To lower
OFAN Cool state
(*1) If State C, change to B
If State B, change to A
CONTENTS