12-5
CONTROL SYSTEM
SM YBD018 1-A.1 GB
Cooling heating
20
(27-7)
24
(20+4)
Relay On; Triac Off
Default Selection
Relay Off; Triac On
OAT
Minimum
Condensing pressure
22
(15+7)
26
(20+4)
Relay On; Triac Off
Default Selection
Relay Off; Triac On
OAT
Maximum
Evaporating pressure
x
The Triac and the Relay can never be activated at the same time
12.1.8
EEV (electronic Expansion valve) Control
EEV opening is defined as EEV = EEV
OL
+ EEV
CV
x
EEV
OL
is the initial EEV opening as a function of the compressor frequency, operation mode,
unit model and capacity.
x
EEV
CV
is a correction value for the EEV opening that is based on the Target CTT and
discharge superhea.
x
During the first 5 minutes of compressor operation EEV
CV
= 0.
x
Once the first 5 minutes are over, the correction value is calculated as follow: EEV
CV
=
EEV
SH Discharge
+ EEV
Target CTT
x
EEV
SH Discharge
For cooling, SH
DischargeC
= CTT- OMT
For Heating, SH
DischargeH
= CTT- ICT
x
EEV
Target CTT
For cooling,
Target CTT
=
Target_CTT_Alpha_C
*OMT
-
Target_CTT_Beta_C
*ICT
+
Target_CTT_Gamma_C
*Actual Compressor Frequency
+
Target_CTT_Delta_C
For Heating,
Target CTT
=
Target_CTT_Alpha_H
*ICT
-
Target_CTT_Beta_H
*OCT
+
Target_CTT_Gamma_H
*Actual Compressor Frequency
+
Target_CTT_Delta_H
12.1.9
Reversing Valve (RV) Control
Reversing valve is on in heat mode.
Switching of RV state is done only after compressor is off for over 3 minutes.
12.2
Fan Mode
In high/ medium/ low indoor fan user setting, unit will operate fan in selected speed.
In AutoFan user setting, fan speed will be adjusted automatically according to the difference
between actual room temperature and user set point temperature.
