Other Wiring - IBC SL Series Installation & Operating Manual

the second pair for #2 etc. Once the controller is programmed for the respective loads, the boiler
manages all the loads without need of further relays (for loads up to 1/3 HP for more – use a
protective relay).
3.13.2.2 Boiler pump
The boiler (primary) pump is powered by the white/yellow wire from the pair labeled "Boiler Pump".
This lead is factory wired to the controller (and its 120 VAC supply) at the upper right backside of
the controller board. Do not attempt to connect the primary pump to the Pump/ Zone Valve
Terminal Block along the controller's right edge - this is for the secondary pumps and/or zone
valves only. Connect the pump's Black wire to the Yellow of this pair (switched Hot). The White/
Yellow pair should be individually capped if the primary pump does not obtain its power from this
pair (e.g. if a variable speed primary pump is connected to the mains power).
Pumps can be switched on/off using the touchscreen controller, so there is no need for temporary
pump wiring during system filling / air purging.
The combined current of all load pumps connected through the on-board pump relays should not
exceed 10 amps. The control circuit board is protected using on-board field replaceable fuses.
Each pump is fused with a separate 5 Amp fuse. The Alarm contact is fused with a 5 Amp fuse and
the 24VAC boiler control circuit is protected with a 2 Amp fuse.
The VS output leads are not commonly used except when providing a variable speed signal to the
fan in an IBC air handler.

3.13.3 Other wiring

Danger
Do not connect sensors to "Therm" terminals. Overheating components can result in
serious personal injury and/or property damage.
Other optional low voltage connections to the control board include:
Two auxiliary Interlocks - for external safety devices as may be required by some
jurisdictions, such as an external low-water cutoff.
Contacts for indoor and outdoor temperatures sensors associated with reset heating. A
10K ohm thermister (resistor dependent on temperature) for outdoor reset sensing is
supplied with the boiler for improved comfort and combustion efficiency.
One pair for a DHW tank sensor. Connect to "DHW S" (not the respective Therm. 1,2,3,4
location) and the boiler automatically detects and calls a smart DHW routine.
One pair of contacts for remote secondary loop temperature control.
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Section: Installation