Other Wiring; Zone Valve Hook-Up - IBC Sl Series Installation & Operating Manual

pump is fused with a separate 5 Amp fuse. The Alarm contact is fused with a 5 Amp fuse and the
24 VAC 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.
One pair (marked BoilerNet) for network connection – this is used for connecting multiple
IBC modulating appliances for autonomous staging.
The bottom pair of contacts (labeled 'External Control') receives a 0-10VDC (default) or
4-20 mA signal from an external boiler controller for direct throttle control. The boiler's
own sensors act as high limits only. The user must enter maximum and minimum boiler
supply temperatures.
Note
Sensors connected to any sensor input contacts must be of the NTC Thermister type
with a resistance of 10,000 ohms at 77°F (25°C) and β = 3892. We do not
recommend using 3rd party supplied sensors. Compatible water temperature
sensors and outdoor sensors can be supplied by your IBC distributor.

3.13.4 Zone valve hook-up

If using zone valves instead of pumps to manage multiple heating loads:
1. Provide 24VAC for the zone valves to the power contacts on the Pump/ Zone Valve
terminal block.
2. Disconnect the 120VAC leads connected to PV-L/PV-N and cap off.
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Section: Installation