Daikin EWAA016DAV3P - Page 43

6 | Application guidelines
Installer reference guide
43
EWAA011~016DA + EWYA009~016DA
Packaged air-cooled water chillers
and packaged air to water heat pumps
4P620242-1 – 2020.06
NOTICE
▪ Make sure the bivalent hysteresis has enough differential to prevent frequent
changeover between outdoor unit and auxiliary boiler.
▪ Because the outdoor temperature is measured by the outdoor unit air
thermistor, install the outdoor unit 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.
Changeover to external heat source decided by an auxiliary contact
▪ Only possible in external room thermostat control AND one leaving water
temperature zone (see "6.2Setting up the space heating/cooling system"[428]).
▪ The auxiliary contact can be:
- An outdoor temperature thermostat
- An electricity tariff contact
- A manually operated contact
- …
▪ Setup: Connect the following field wiring:
L
N
H Com
A
K2AK1A
X2M
B
TI
K2AK1A
Outdoor/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 outdoor unit (field supply)
K2A Auxiliary relay for activation of boiler (field supply)
Outdoor Outdoor unit
Auto Automatic
Boiler Boiler
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