EKHBH/X008BA
Indoor unit for air to water heat pump system
4PW54185-1B
Installation manual
27
[7] DT for booster heater and dual set point control
DT for booster heater
Applies only to installations with a domestic hot water tank.
When the domestic hot water is heated and the domestic hot water
set point temperature (as set by the user) has been reached, the
booster heater will continue to heat the domestic hot water to a
temperature a few degrees above the set point temperature, i.e. the
booster heater OFF temperature. These extra degrees are specified
by the domestic hot water step length field setting. Correct setting
prevents the booster heater from repeatedly turning on and off (i.e.
chattering) to maintain the domestic hot water set point temperature.
Note: the booster heater will turn back on when the domestic hot
water temperature drops [7-01] (field setting) below the booster
heater OFF temperature.
■
[7-00]
Domestic hot water step length: temperature
difference above the domestic hot water set point
temperature before the booster heater is turned off.
■
[7-01]
Hysteresis value booster heater: temperature
difference determining the booster heater ON temperature
(T
BH ON
). T
BH ON
= T
BH OFF
– [7-01]
Dual set point control
Applies only to installations with different heat emitter which require
different set points.
Dual set point control makes it possible to generate 2 different set
points.
■
[7-02] Dual set point control status: defines whether the dual
set point control is enabled (1) or disabled (0).
■
[7-03] Second set point heating: specifies the second set
point temperature in heating operation.
■
[7-04] Second set point cooling: specifies the second set
point temperature in cooling operation.
If the schedule timer for booster heater (see the operation
manual) is active, the booster heater will only operate if
allowed by this schedule timer.
BH
Booster heater
HP
Heat pump. If heating up time by the heat pump takes too
long, auxiliary heating by the booster heater can take place
T
BH OFF
Booster heater OFF temperature (T
U
+ [7-00])
T
BH ON
Booster heater ON temperature (T
BH OFF
– [7-01])
T
HP MAX
Maximum heat pump temperature at sensor in domestic hot
water tank
T
HP OFF
Heat pump OFF temperature (T
HP MAX
– [6-01])
T
HP ON
Heat pump ON temperature (T
HP OFF
– [6-00])
T
DHW
Domestic hot water temperature
T
U
User set point temperature (as set on the user interface)
t
Time
WARNING
Be aware that the domestic hot water temperature will be
automatically increased (always) with the value selected in
field setting [7-00] compare to the user set point for
domestic hot water (T
U
). Refer to field setting [7-00] and
the operation manual to select preferable set point.
If this high water temperature can be a potential risk for
human injuries, a mixing valve (field supply) shall be
installed at the hot water outlet connection of the domestic
hot water tank. This mixing valve shall secure that the hot
water temperature at the hot water tap never rise above a
set maximum value. This maximum allowable hot water
temperature shall be selected according to local and
national regulations.
If the booster heater operation is limited ([4-03]=0), then
set point of field setting parameter [7-00] has only meaning
for powerful domestic water heating.
t
T
BH ON
T
DHW
T
HP ON
T
HP OFF
T
HP MAX
T
U
T
BH OFF
[6-01]
[6-00]
[7-00]
[7-01]
T
U
= 70
°
C
[7-00] =
3
°
C
[6-01] =
2
°
C
[6-00] =
7
°
C
HP
BH
HP
5
10
20
30
40
41
48
50
60
71
70
73
The minimum value for booster heater ON
temperature (T
BH ON
) is 2°C (fixed) below heat pump
OFF temperature (T
HP OFF
).
NOTE
There is no indication available which set point is
active!
NOTE
■
The first set point heating/cooling is the set point
selected on the user interface.
-
In heating mode the first set point can be a
fixed value or weather dependent.
-
In cooling mode the first set point is always a
fixed value.
■
The second set point heating [7-03] should be
linked to the heat emitters which requires the
highest set point in heating mode. Example: fan
coil unit.
■
The second set point cooling [7-04] should be
linked to the heat emitters which requires the
lowest set point in cooling mode. Example: fan
coil unit.
■
The actual second set point heating value
depends on the selected value of setting [7-03].
-
In case [7-03]=1~24, the actual second set
point will be first set point heating increased
with [7-03] (the maximum is 55°C).
In this way the second set point heating is
linked to the first set point heating.
-
In case [7-03]=25~55, the actual second set
point heating is equal to [7-03].
■
The selection of second set point or first set point
is determined by the terminals (X2M: 1, 2, 4).
The second set point has always priority on the
first set point.
When dual set point control is enabled, heating/cooling
selection always has to be done on the user interface.
NOTE
It is the responsibility of the installer to make sure no
unwanted situations can occur.
It is very important that the water temperature to the
floor heating loops never becomes too high in heating
mode or never too cold in cooling mode. Failure to
observe this rule can result in construction damage or
discomfort. For example in cooling mode condensation
on the floor can occur when water towards the floor
heating loops is too cold (dew point).
X2M
1
2
3
4
SP1
SP2
SP1
First set point contact
SP2
Second set point
contact
