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Installation, operation and maintenance instructions - VMGFE102
13.4 - Supplementary electric resistance heaters
To permit staging of the capacity reduction of the heat pump
at low ambient temperatures, as shown in the diagram below, it
is possible to install supplementary electric heaters in the
leaving water line. Their capacity can compensate for the
capacity drop of the heat pump.
These heaters can be controlled via an electronic card
mounted on a board (accessory).
Four outputs are available to control the heater contactors
(not supplied with the board), permitting gradual compen-
sation of the heat pump capacity reduction.
These outputs are confi gurable to obtain a choice of two,
three or four stages. The last stage will only be activated after
a shut-down of the heat pump following a fault con-dition
(safety device).
In the diagram below “example of additional electric heaters”
the capacity of the four heaters is the same as the capacity of
the heat pump at 7°C outdoor air temperature.
This requires only a 400 V-3 ph-50 Hz power supply source, as
well as a connection to the unit via a communication bus.
For the required confi guration of the stages, consult the AR05
017-160 Control manual.
Legend
1
Electric heater power supply 400 V-3 ph-50 Hz
2
Accessory control board for four additional electric heaters
3
Internal communication bus
4
Heater stage control contactors
5
Power supply for additional heaters
6
Supplementary electric resistance heaters
Typical accessory installation diagram
Legend
1 Stage
1
2 Stage
2
3 Stage
3
4 Stage
4
A
Heat pump capacity variation as a function of the air temperature
B
Building thermal load
C
Balance point between the capacity supplied by the heat pump and the thermal load of the building
Operating range, in which the heat pump capacity is lower than the building thermal load
Operating range, in which the heat pump capacity is higher than the building thermal load
Outdoor air temperature, °C
P
ump capacit
y,
%
Example of additional electric heaters
1
A
2
3
4
B
120
100
80
60
40
20
0
-15
-10
-5
0
5
10
15
1
1
2
C
1
2
3
4
6
5
