SSB 6720866942 (2018/06) US
Installation | 21
Front Door
Cover (removed)
Main Switch
(backside view)
905 TS touchscreen
(backside view)
905 TS touchscreen
Power Supply (24V)
Fig. 25 Front Door: Backside layout
NOTE: All electrical conduit and hardware must be installed so that it
does not interfere with the removal of any unit covers, inhibit service/
maintenance, or prevent access between the unit and walls or another
unit.
4.5 Access to the electrical terminal strips
Each unit is fully wired from the factory with an internal operating control
system. No eld control wiring is required for normal operation.
However, the control system used with all SSB boilers does allow for
some additional control and monitoring features. Wiring connections for
these features are made on the Input / Output (I/O) terminal strips located
behind the removable cover of the electrical box, as shown in Fig. 26.
NOTE: Any electrical load connected to the terminal strip (external
pumps, air damper, alarm) must be powered through a relay, not included
in the boiler, to be provided and wired by the installer.
Enable
Disable
HIGH VOLTAGE TERMINAL STRIP
LOW VOLTAGE TERMINAL STRIP
115
L
113 114
120 VAC
N
112110111107 108109
103
N
101 102
Main Pump
L
N
Pump DHW/
L N
3 WAY CH
L
116 117 118
N
PUMP RELAY
L
3-WAY DHW
Pump CH
ALARM
ON/OFF MODULES
L N
104 105106
MAIN SUPPLY
119 120121
NL
EXT. IGNITER
122 123124
NL
EXT. IGNITER
Fig. 26 I/O Terminal Strips
4.5.1 Enable/Disable(Room Thermostat Connection)
The Room Thermostat (Enable/Disable) terminals (dry contacts) come
pre-wired closed (jumped) from the factory. For connecting a room
thermostat, the jumper must be removed and the thermostat wires must
be connected to terminals 9 and 10, as shown in Fig. 26.
4.5.2 Outdoor Temperature Sensor
If outdoor temperature sensor is to be used, the outdoor probe needs
to be connected to terminals 3 and 4 as shown in Fig. 26. The outdoor
probe shall be installed on an outer wall, North or North/East, away from
windows, door, and ventilation grids.
Never install the probe in a position exposed to the sun.
The maximum length is 300’ (100 meters), if the cable length exceeds
32’ (10 meters) a shielded cable is required and shall be connected to
chassis ground.
NOTE: All sensors and low voltage wiring shall not be routed in direct
contact or near high voltage power.
4.5.3 Electrical wiring diagram
See”Appendix A - Wiring diagram”
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