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

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.
3. Use a separate transformer – the 40 VA appliance inside the wiring box is for internal systems
only.
4. Wire individual load/zone valves to their associated contacts on the secondary pump/zone
valve connector. Do not confuse such "load/zone valves" with similar valves used to
segregate a single load type (e.g., those used on a zoned radiant floor) – see the next section.
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3.13.3 Other wiring