SmartPlate Installation, Operation & Maintenance Manual
CHAPTER 1
– GENERAL INFORMATION
OMM-0069_0H
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audible alarm and cuts off power to the Control Valve Actuator thereby closing the Control Valve
and shutting off the boiler water flow to the unit.
The Boiler Water inlet and outlet temperatures are sensed on the surface of the inlet/outlet
pipes and are provided for informational and troubleshooting purposes only. They are not used
for temperature control but they do have alarm limits available for customer settings, if desired.
The Control Box components are housed in a steel enclosure with a hinged front door. This
door contains a clear polycarbonate window which permits maintenance personnel to view the
controls and displays of the Temperature Controller, and other display devices mounted on a
recessed panel behind the door. All sensor and control signal connections are made via cable
connections at the bottom of the Control Box. External AC power (120 VAC, 60 Hz, 220 VAC 50
Hz or 220V, 60 Hz) is supplied via the cutout on the bottom of the Control Box. If desired, the
Control Box can be easily repositioned in 90° increments from its default position shown in
Figure 1-1. Refer to Chapter 2, section 2.3.3 for details.
1.2.2 FEED-FORWARD TEMPERATURE SENSORS
The Feed-Forward Temperature Sensor (Type J thermocouple) is installed in the cold water
inlet mixing box on the unit. The Temperature Sensor monitors a portion of the inlet flow to the
unit and provides a feed-forward signal to the Temperature Controller which is proportional to
the change in flow through the unit.
1.2.3 OUTLET TEMPERATURE SENSORS
The Control System includes a Dual Temperature Sensor which is installed in the hot water
outlet of the unit. This sensor contains two identical Type J thermocouples. The first
thermocouple connects directly to the Temperature Controller to provide feedback PID control
for the outlet water temperature. The second thermocouple connects to the Over-Temperature
Indicator/Switch in the Control Box.
1.2.4 BOILER WATER INLET/OUTLET TEMPERATURE SENSORS
Two additional Temperature Sensors (Type J thermocouples) are provided with the Control
System. One Temperature Sensor is attached to the boiler water inlet and the other is attached
to the boiler water outlet of the unit. These two Sensors are connected to two identical
Temperature Display Indicators in the Control Box to provide real-time indications of the inlet
and outlet boiler water temperatures. These Temperature Indicators are physically identical to
the Over-
Temperature Indicator/Switch, but are used as “Indicator-Only” devices and do not
provide any switching functions. However, the Boiler Water Inlet Indicator will signal an alarm
condition if the boiler water temperature exceeds 250°F.
