46 Installing the System Piping
3.7.13 DHW Priority
The DHW priority provides output through the boiler controller.
When the DHW mode is on while there is a space heating demand,
the DHW priority’s contact is on. Other than during this status, the
DHW priority’s contact is off. Use a DHW priority to check the status
of the zone controller or DHW priority.
3.7.14 Boiler State
The boiler state contact outputs from the boiler controller. The
boiler state contact is turned on during combustion. Other than
this status, the boiler state contact is turned off. Use a boiler state
contact to check the boiler status.
3.7.15 Boiler Error
The boiler error contact provides a boiler error status. The boiler
error contact is turned on when an error occurs. Other than this,
the boiler error contact is turned off. Use a boiler error contact to
check the boiler error status.
3.7.8 Auto Reset Safety Switch
Connect an external safety device, such as a louver switch or a
low gas pressure switch, to the AUTO terminal (CNC10). Only
external safety devices with relay output contacts are available. An
error alert from the connected external safety device is released
automatically based on the connected external safety device
settings.
Note
To select the contact type for the connected
external safety device, tap the Set button (
) > Ext
Connection on the screen, and then select N-Open
(Normal open type) or N-Closed (Normal closed type)
on the Auto Reset Safety Switch menu.
3.7.9 Modbus/BACnet
If a Modbus or BACnet gateway is installed, connect the RS-485
cables to the 3-pin terminal block located on the right side of the
front panel. For detailed wiring information, refer to the Modbus
RTU or BACnet Installation manual.
Note
To provide sufficient communication quality and
sensitivity, use twisted pair cables such as UTP or CAT5
cables.
3.7.10 0–10 V VDC Input
Connect a 0–10 V VDC input signal to the 0-10V IN terminal
(CNU1), if the BMS system requires 0–10 V signals to control the set
temperature.
Note
If the BMS Status menu on the EMS Set menu is set
to Enabled, the set temperature is automatically
controlled based on the input signals.
3.7.11 0–10 V VDC Output
Depending on the space heating control methods, the supply or
return water temperature can be measured with 0–10 V signal
output. The current temperature in the BMS system can be
monitored using this signal output.
3.7.12 Air Handler
The air handler provides output through the boiler controller
depending on the space heating operation status. If space heating
is in operation, the air handler’s contact is on. If the space heating
is not in operation, the air handler’s contact is off. When using an
air handler, set the air handler to operate during the operation of
space heating only.
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