11-3
CONTROL SYSTEM
SM BS DCI 1- A.1 GB
11.4 Indoor
Fan
Control
10 Indoor fan speeds are determined for each model. 5 speeds for cool/dry/fan
modes and 5 speeds for heat mode.
When user sets the indoor fan speed to a fixed speed (Low/ Medium/ High), unit
will operate constantly at set speed.
When Auto Fan is selected, indoor unit controller can operate in all speeds. The
actual speed is set according to the cool/heat load.
11.4.1
Turbo Speed
The Turbo speed is activated during the first 30 minutes of unit operation when
auto fan speed is selected and under the following conditions:
x
Difference between set point and actual room temperature is bigger then 3
degrees.
x
Room temperature > 22 for cooling, or < 25 for heating.
11.5 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.
11.6 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, and outdoor air temperature (OAT) and
heat sink temperature (HST).
Routine
Conditions
A
Heating with OAT < 15
0
C
or
Cooling with OAT > 20
0
C, or HST > 50
0
C
or
Faulty OAT
B Cooling
with
20
0
C > OAT > 7
0
C
C
Cooling with 7
0
C > OAT
D
Heating with OAT > 15
0
C
CONTENTS
