Daikin Altherma 3 H MT F - Page 51

6 | Application guidelines
Installer reference guide
51
EPRA08~12EAV3+W1 + ETVH12SU18+23EA6V
Daikin Altherma 3 H MT F
4P644482-1 – 2021.03
L
N
H Com
A
K2AK1A
X2M
B
TI
K2AK1A
Indoor/Auto/Boiler
35 30 X Y
Indoor
B
TI
Boiler thermostat input
A Auxiliary contact (normally closed)
H Heating demand room thermostat (optional)
K1A Auxiliary relay for activation of indoor unit (field supply)
K2A Auxiliary relay for activation of boiler (field supply)
Indoor Indoor unit
Auto Automatic
Boiler Boiler
NOTICE
▪ Make sure the auxiliary contact has enough differential or time delay to prevent
frequent changeover between indoor unit and auxiliary boiler.
▪ If the auxiliary contact is an outdoor temperature thermostat, install the
thermostat in the shadow so that it is NOT influenced or turned ON/OFF by direct
sunlight.
▪ Frequent changeover may cause corrosion of the auxiliary boiler. Contact the
manufacturer of the auxiliary boiler for more information.
Setpoint of the auxiliary gas boiler
To prevent freeze-up of the water piping, the auxiliary gas boiler must have a fixed
setpoint ≥55°C, or a weather-dependent setpoint ≥T
min
.
0
–30 –25 –20 –15 –10 –5 0 5
20
30
40
50
60
10
T
a
(°C)
T
min
(°C)
T
a
Outdoor temperature
T
min
Minimum weather-dependent setpoint for auxiliary gas boiler