41
9.5
Fuses
The four fuses of the S-CB
+
400/550 are located on the PCBs: two fuses on each circuit board.
Fuse no.
Application
Fused value
Fuse type
F1
Pump 1
Pump 2 / TWV
250 VAC 5AT H
5 AT ceramic filled fuse
F2
Switch mode supply
Gas valve
Pump3
External ignition
250 VAC 5AT H
5 AT ceramic filled fuse
These boilers are not phase sensitive.
9.6
List for connections
1-2
OUTDOOR SENSOR
When an outside temperature sensor is connected, the boiler will control the flow water temperature by
using a calculated setting, which is relative to the outside temperature. PARAMETER: No parameter set-
tings needed.
3-4
EXTERNAL FLOW SENSOR
When a low velocity header is used, this external flow sensor measures the flow temperature at the system
side. The sensor must be mounted on the supply pipe at the system side, just behind the low loss header.
NOTICE: The sensor must be used when several boilers are cascaded with the internal cascade manager.
PARAMETER: No parameter settings needed.
5-6
CALORIFIER SENSOR or THERMOSTAT
When an indirect hot water tank / calorifier is installed, a hot water sensor must be connected to these
terminals. In case of a DHW heat demand, the set point will be shown in the display. An external on/off
thermostat can also be connected to these terminals. When there is heat demand (terminal 5 and 6 are
bridged) the flow temperature going to the heating coil(s) will be shown in the display.
7-8
GENERAL BLOCKING
A heat demand that will start the burner will be blocked when terminals 7 and 8 are not bridged. This
connection is for the use of external safety devices (Terminals must be bridged for allowing burner to fire).
PARAMETER: A parameter change is needed.
9-10
EMPTY
11-12
EXTERNAL WATER PRESSURE SWITCH
A water pressure sensor is mounted in the boiler. As an option a water pressure switch can be installed.
The sensor can be replaced by the water pressure switch, which can be wired to the terminals. When
terminals 11-12 are not bridged, the boiler will lock-out. PARAMETER: A parameter change is needed
(P4AD).
13-14
ON/OFF STAT OR OPENTHERM HEATING CIRCUIT
OPTION 1: An ON/OFF thermostat can be connected. The boiler will use the set/programmed flow tem-
perature for the heating system when these terminals 13 and 14 are bridged.
OPTION 2: When using an OpenTherm (OT) controller connected to the terminals 13 and 14. The boiler
software will detect and use this OpenTherm signal automatically.
15-16
0-10 VDC CONTROL SIGNAL
These terminals are used for an external 0-10 VDC control signal. PARAMETER: A parameter change is
needed. NOTICE: Terminal 15 [+] (positive) and Terminal 16 [-] (negative).
17-18
CASCADE CONNECTION
These connections are used when boilers are cascaded with the internal cascade manager for controlling
the total cascade. NOTICE: Connect all terminals 17 and all terminals 18 together, do not switch between
these terminals.
Use only shielded cable to connect the next boiler!
