14
6155049
Connecting external sensors and control devices
(cont.)
Installation sequence
FN – Programmable function input
(only type VMN3)
A short-circuited FN contact caused by an external
appliance will lead to specific boiler behaviour,
depending on the input configuration
[Configuration >
FN input]
:
■
Maintain the frost protection temperature
regardless of the set room temperature
■
Maintain a comfortable temperature regardless
of the set room temperature
■
Charge the buffer cylinder with limited user
intervention outside the schedule (integration
of boiler and PV installation).
MA – Master appliance
To limit power consumption, boiler operation can be
made dependent on other collectors, such as the
DHW cylinder. To do this, it must be connected to the
MA N/C contact to activate the main current receiver
and open the contact. This blocks the boiler's heating
operation and stops the DHW circulation pump.
RT – (alternative room temperature controller,
type VMN3)
Optional control of boiler operation depending on
current room temperature. The RT input must be
activated
[Configuration > Room temperature > RT]
,
which causes the floating RT contact switches of the
central heating to short circuit. If the RT input is
activated, the room temperature controller integrated
in the boiler is switched off. We recommend using the
temperature sensor set at the factory in conjunction
with the integrated room temperature controller for
the boiler.
RT – (alternative room temperature controller,
type VLN3)
Control of boiler operation depending on room
temperature. An RT short circuit leads to central heating.
The room temperature controller (RT) must be installed
in a room typical of the building and as far away as
possible from radiators, windows, doors and
passageways. If the contact is not live, the controller
opens when the required room temperature is reached.
Tcyl – Temperature sensor for DHW cylinder
The water temperature sensor in the DHW cylinder
must be positioned in the cylinder connector.
Tos – Outside temperature sensor (only type VMN3)
The sensor must be installed in a dark location on the
north or north-west façade of the building and away
from windows and fans. The temperature sensor cable
must be as short as possible and must not be routed
in the immediate vicinity of power cables.
Tr – Room temperature sensor (only type VMN3)
The room temperature sensor must be installed in a
room typical of the building and away from radiators,
windows, doors and hallways.
RS485 – Communication range
Terminals for additional heating circuit controllers.
PUMP.C – DHW circulation pump
Controls the DHW circulation pump in the daily/weekly
schedule. The function must be activated
[Configuration > Circulation > YES]
.
TWV – three-way valve control
(central heating/DHW)
Changes boiler operation over to central heating or
DHW heating in the heating coil of the DHW cylinder
by means of a three-way isolating valve with
servomotor. Depending on the model used
(SPST or SPDT control), the appliance must
be connected as shown in the illustrations.
SPST control
SPDT control
M.SUPPLY
TWV
L
N
PE
LB LA
N
Control
N
Note
To activate the DHW function as described in
Service/Configuration – Cylinder
.
Caution
An incorrect electrical connection will result in
damage.
Do not connect the FN, MA, RT, Tcyl, Tos, Tr
inputs when they are supplied with power!
TWV
LB LA
N
LA
LB
N
A
Mains supply to main PCB
B
DHW circulation pump
C
Three-way valve control
(central heating/DHW)
D
Internal pump
E
PWM signal for internal pump
M.SUPPLY
PUMP.C
TWV
PUMP
L
N
PE
L
N
PE LB LA
N
L
N
PE
PUMP
O G I
L N PE
A
B
C
D
E