Low Voltage (Tb1) Terminal Block - Harsco Industrial SC-1500 Owner's Manual

Refer to
the electrical connections.
Relays A thru D can be user-configured through the NURO touch screen
interface to control devices such the Comfort Heat (CH) Pump, Domestic Hot
Water (DHW) Pump, Air Damper, System Pump, etc.
Master Alarm Relay – The Master Alarm Relay terminals are normally-open dry contacts that close in the
event of an alarm output from the boiler control.

3.2.5 Low Voltage (TB1) Terminal Block

Enable/Disable –
TB1-1
these terminals is user-configurable through the NURO controls, but generally closure of the Enable/Disable
circuit provides a call for heat to the boiler. Opening this circuit prevents the boiler from running.
The boiler ships with a factory-installed jumper across the Enable/Disable terminals. This circuit is energized
with a potential, so the contacts on any remote enable devices must be rated for minimum
24VAC
4-20mA Analog Input –
the boiler. This analog signal can be used to change the boiler's operating setpoint or firing rate.
Spare Analog Input –
HDR Temp Sensor –
installed in the primary hydronic system piping, downstream of all the boilers. This temperature sensor must
be a 2-wire 12k NTC thermistor. This circuit is energized by the boiler with a
DHW Stat/Sensor –
TB1-9
temperature sensor installed in a domestic hot water storage tank. If using an aquastat, use a SPST
normally-closed, break on rise type with either a fixed or adjustable deadband above and below the setpoint.
Alternatively, if using a temperature sensor, it must be a 2-wire 12k
length to measure an accurate storage tank temperature. This circuit is energized by the boiler with a
potential.
Outdoor Temp Sensor –
allows the NURO control to be programmed to run an outdoor air schedule. The outdoor air temperature sensor
must be a 2-wire 12k
from direct sunlight exposure. This circuit is energized by the boiler with a
Night Setback –
TB1-13
Night Setback circuit enables the Night Setback mode which reduces the boiler's operating setpoint. Opening
this circuit resumes normal operation. This circuit is energized by the boiler with a
contacts on the day/night timer must be rated for minimum
4-20mA Analog Output –
firing rate. When operating at full power (maximum firing rate), the boiler will provide a 20mA output. When
operating at minimum power (minimum firing rate), the boiler will provide a 4mA output.
Ground – provides an equipment (frame) ground connection for input, output, or communication
TB1-17
connections. For independently powered control devices, it may be necessary to create a common ground.
Section 6 Parts and Tech Support
and can be used to remotely enable or disable the boiler. The functionality of
TB1-2
and can be used to provide a remote analog 4-20mA control signal to
TB1-3 TB1-4
and are reserved for future use.
TB1-5 TB1-6
and can be used to connect a remote header temperature sensor,
TB1-7 TB1-8
and can be used to connect either an aquastat or remote DHW
TB1-10
and
TB1-11 TB1-12
NTC thermistor and should be installed on the North face of the building and shielded
and can be used to connect a day/night or occupancy timer. Closure of the
TB1-14
and
TB1-15 TB1-16
NOTE
for proper wiring and configuration of
can be used to connect an outdoor air temperature sensor which
.
5VDC
provide a 4-20mA analog output signal which tracks the boiler's
TM
P-K SONIC Gas Fired Boiler
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potential.
5VDC
NTC thermistor and be of sufficient
potential.
5VDC
potential, so the
5VDC
.
24VAC
5VDC