Watts AERCO SmartPlate SP23 Instruction manual

Single Wall Heater Models:
Double Wall Heater Models:
SP23, SP33, SP45, SP69, SP150
SPDW23, SPDW32, SPDW42, SPDW61,
SPDW113
Installation, Operation & Maintenance Manual
SmartPlate Domestic
Hot Water Heaters
OMM-0069_0H •SP-100 •1/30/2020

SmartPlate Installation, Operation & Maintenance Manual
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Table Of Contents
GENERAL INFORMATION................................................................................ 5
1.1 INTRODUCTION ................................................................................................................................... 5
1.2 ELECTRONIC CONTROL SYSTEM/SMARTPLATE (ECS/SP) .................................................................... 6
1.2.1 Control Box Assembly................................................................................................................... 7
1.2.2 Feed-Forward Temperature Sensors............................................................................................ 8
1.2.3 Outlet Temperature Sensors ........................................................................................................ 8
1.2.4 Boiler Water Inlet/Outlet Temperature Sensors .......................................................................... 8
1.3 SMARTPLATE PIPING ASSEMBLIES ...................................................................................................... 9
1.4 ELECTRONIC CONTROL VALVE, MXG-461............................................................................................ 9
INSTALLATION................................................................................................11
2.1 INTRODUCTION .................................................................................................................................11
2.2 RECEIVING AND UNPACKING SMARTPLATE......................................................................................11
2.3 SITE SELECTION AND PREPARATION .................................................................................................12
2.3.1 Installation Clearances................................................................................................................ 12
2.3.2 Setting the Unit........................................................................................................................... 13
2.3.3 Repositioning ECS/SP Control Box.............................................................................................. 14
2.4 HEATING FLUID AND DOMESTIC HOT WATER (DHW) PIPING...........................................................15
2.5 SMARTPLATE ELECTRICAL WIRING CONNECTIONS...........................................................................16
2.6 ADDITIONAL COMPONENT INSTALLATION ....................................................................................... 21
FUNCTIONAL DESCRIPTION..........................................................................23
3.1 INTRODUCTION .................................................................................................................................23
3.2 MECHANICAL OVERVIEW .................................................................................................................. 23
3.3 ELECTRONIC CONTROL OVERVIEW ...................................................................................................24
3.4 OVER-TEMPERATURE CONTROL AND SAFETY FEATURES ................................................................. 24
ADJUSTMENT..................................................................................................27
4.1 INTRODUCTION .................................................................................................................................27
4.2 SMARTPLATE 3-WAY CONTROL VALVE, MXG-461 ADJUSTMENT ..................................................... 27
4.2.1 Control Valve Calibration and Status Indications ....................................................................... 27
4.2.2 Manual Control of 3-Way Valve –Removable Handwheel to Hamper Tampering.................... 30
4.2.3 Setpoint Temperature Adjustment ............................................................................................ 31
4.2.4 Over-Temperature Alarm Limit Adjustment .............................................................................. 34
OPERATION.....................................................................................................37
5.1 INTRODUCTION .................................................................................................................................37
5.2 PRE-OPERATIONAL CHECKS & PROCEDURES ....................................................................................37
5.3 INITIAL START-UP ..............................................................................................................................38
5.4 CHECKING MIXED INLET TEMPERATURE...........................................................................................39
5.5 SHUTTING DOWN THE SYSTEM......................................................................................................... 39
SCHEDULED MAINTENANCE.........................................................................41
6.1 INTRODUCTION .................................................................................................................................41
6.2 BOILER WATER DIFFERENTIAL PRESSURE GAUGE CHECK ................................................................. 42
6.3 PLATE PACK LEAKAGE CHECKS (DOUBLE-WALL MODELS ONLY)....................................................... 43
6.4 OVER-TEMP SWITCH CHECK..............................................................................................................43
6.5 STRAINER INSPECTION AND CLEANING ............................................................................................44
6.6 CONTROL VALVE OPERATIONAL CHECK............................................................................................44
6.7 TEMPERATURE SENSOR CHECKS ....................................................................................................... 44
6.8 RECIRCULATION PUMP CHECK .......................................................................................................... 45

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6.9 PERIODIC CLEANING OF HEAT EXCHANGER......................................................................................46
TROUBLESHOOTING......................................................................................47
7.1 INTRODUCTION .................................................................................................................................47
7.2 TROUBLESHOOTING PROCEDURES ................................................................................................... 47
CORRECTIVE MAINTENANCE........................................................................57
8.1 INTRODUCTION .................................................................................................................................57
8.2 SINGLE WALL HEAT EXCHANGER MAINTENANCE ............................................................................. 57
8.3 HEAT EXCHANGER CLEANING & DE-SCALING ...................................................................................57
8.4 SINGLE-WALL HEAT EXCHANGER REPLACEMENT ............................................................................. 60
8.5 DOUBLE-WALL HEAT EXCHANGER MAINTENANCE........................................................................... 63
8.6 DOUBLE-WALL HEAT EXCHANGER CLEANING...................................................................................64
8.6.1 Heat Exchanger Cleaning and De-Scaling (In-Place Method) ..................................................... 64
8.6.2 Heat Exchanger Cleaning By Disassembly ..................................................................................64
8.7 DOUBLE-WALL HEAT EXCHANGER OPENING AND CLOSING.............................................................66
8.7.1 OPENING HEAT EXCHANGER ......................................................................................................67
8.7.2 REMOVAL AND INSERTION OF PLATES.......................................................................................69
8.7.3 CLOSING HEAT EXCHANGER ....................................................................................................... 70
8.8 DOUBLE-WALL HEAT EXCHANGER GASKET REPLACEMENT.............................................................. 73
8.8.1 Replacing Gaskets on Channel Plates .........................................................................................73
8.8.2 Replacing Gaskets on End Plate (First Plate Against Frame Plate) ............................................. 74
8.9 DOUBLE-WALL HEAT EXCHANGER REPLACEMENT ...........................................................................76
8.10 CONTROL VALVE ELECTRONIC MODULE REPLACEMENT AND VALVE REMOVAL ........................... 80
8.10.1 Electronics Module Replacement............................................................................................. 80
8.10.2 Control Valve Replacement ......................................................................................................82
8.11 RECIRCULATION PUMP REPLACEMENT........................................................................................... 83
8.12 STRAINERS .......................................................................................................................................85
8.13 ECS/SP CONTROL BOX ASSEMBLY AND COMPONENTS ..................................................................87
8.14 CONTROL BOX ASSEMBLY REPLACEMENT ...................................................................................... 87
8.15 TEMPERATURE CONTROLLER REPLACEMENT .................................................................................88
8.16 OVER-TEMPERATURE SWITCH AND TEMPERATURE INDICATORS..................................................89
8.17 24 VAC STEP-DOWN TRANSFORMER REPLACEMENT .....................................................................90
APPENDIX A ..................................................................................................................................95
APPENDIX B –ECS/SP WIRING DIAGRAM & TERMINAL BLOCK CONNECTIONS ........................105
APPENDIX C –SMART PLATE PIPING DRAWINGS....................................................................... 107
APPENDIX D –DIMENSIONAL DRAWINGS..................................................................................119
APPENDIX E –PART LISTS ...........................................................................................................121
APPENDIX F –RECOMMENDED SPARE PARTS ........................................................................... 131

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GENERAL INFORMATION
1.1 INTRODUCTION
This manual provides detailed coverage for the AERCO SmartPlate line of Water-to-Water
Heaters. Each SmartPlate Water Heater model is equipped with AERCO’s Electronic Control
System (ECS), specifically designed for SmartPlate (ECS/SP), and an Electronic Control Valve,
MXG-461. This Control System and Valve combination is used with all SmartPlate models and
sizes.
The following SmartPlate Single-Wall and Double-Wall Heat Exchanger Water Heater models
are available:
Type
SmartPlate Models
Pressure
Options *
Power
Options**
Single Wall
SP23, SP33 SP45, SP69, SP150
150 PSI
120V 60 Hz
220V 50 Hz
220V 60 Hz
200 PSI
Double Wall
SPDW23, SPDW32, SPDW42, SPDW61, SPDW113
150 PSI
200 PSI
* Appropriate add-on kits differentiate overall product for given DHW side operating pressure.
** Internal power wiring and recirculation pump differentiates the power option.
Figure 1-1 shows a typical SmartPlate Water Heater with a single-wall heat exchanger. Piping
assembly components are similar for double-wall models. The remaining sections in this chapter
provide descriptions of the units, assemblies and sub-assemblies included with the SmartPlate
models.

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Figure 1-1. Typical SmartPlate Packaged Water Heater –Single Wall Shown
1.2 ELECTRONIC CONTROL SYSTEM/SMARTPLATE (ECS/SP)
Identical Electronic Control Systems are used on all SmartPlate models. This system,
commonly referred to as the ECS/SP, contains a Control Box Assembly which includes all of the
electronic circuitry for the ECS/SP. In addition, the ECS/SP includes several sensors and safety
devices which provide temperature and flow control information to the Control Box circuitry. The
Control Box and the additional devices included in the ECS are shown in Figure 1-2. The
additional devices included in the ECS/SP include:
•Feed-Forward (Mixed Water) Temperature Sensor (Type J Thermocouple)
•DHW Outlet Dual Temperature Sensors (Type J Thermocouples)
•Boiler Water Inlet/Outlet Temperature Sensors (Type J Thermocouples)
•Over-Temperature Alarm (With Safety Shutdown)
ECS
CONTROL
BOX
RELIEF VALVE
CONTROL
VALVE
MXG-461
DOMESTIC
WATER INLET
STRAINER
BOILER WATER
DIFFERENTIAL
PRESSURE GAUGE
DRAIN
VALVE
RECIRCULATION
PUMP
BOILER
WATER INLET
STRAINER
INTAKE
MIXING BOX
HEAT EXCHANGER
(BEHIND SUPPORT ASSY)
BOILER
WATER INLET
DHW OUTLET
COLD WATER
INLET
BOILER WATER
OUTLET

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If desired, the ECS/SP can be ordered with a Modbus communication option. This option
permits the ECS/SP to be externally controlled by an Energy Management System (EMS),
Building Automation System (BAS), or a computer supplied by other manufacturers.
The ECS/SP assemblies and components are described in the following subordinate sections.
DHW
OUTLET DUAL
TEMP. SENSOR
CONTROL
VALVE,
MXG-461
BOILER WATER
IN/OUT
TEMP SENSORS
CONTROL
BOX
RECIRCULATION
PUMP
FEED-FWD
(MIXED WATER)
TEMP. SENSOR
Figure 1-2. Electronic Control System/SmartPlate (ECS/SP)
1.2.1 CONTROL BOX ASSEMBLY
The front panel on the Control Box assembly contains all of the display devices for the ECS/SP.
These include the Temperature Controller, an Over-Temperature Indicator/Switch and Boiler
Water In/Out Temperature Indicators.
The Temperature Controller is the “brain” of the ECS/SP, which processes data received from
the temperature sensors. Using feed forward and PID (Proportional Integral Derivative)
algorithms, the Temperature Controller provides a 0 to 10 VDC control signal to the Control
Valve Actuator, which precisely modulates the Control Valve for optimum DHW outlet
temperature control. The upper display on the front panel of the Temperature Controller displays
the current DHW outlet temperature. The lower display continuously displays the DHW setpoint
temperature currently stored in the Temperature Controller.
The Over-Temperature indicator/switch included in the Control Box constantly monitors and
displays the unit’s outlet temperature to ensure it does not exceed the preset high temperature
limit. The over-temperature limit is factory-set 20°F above the unit’s setpoint temperature
specified on the sales order. If an over-temperature condition occurs, this device sounds an

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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.

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1.3 SMARTPLATE PIPING ASSEMBLIES
The diameter of the piping assemblies furnished with the water heater will depend on the size of
the heat exchanger installed in the SmartPlate model ordered. Smaller sized models utilize 1.5”
piping assemblies, while the larger sizes utilize 2” piping assemblies. Refer to Table 1-1 below
for the size of the piping assemblies used in each Single-Wall and Double-Wall SmartPlate
model.
TABLE 1-1. SmartPlate Model Piping Assemblies
Type
SmartPlate Model
Piping Assembly
Diameter
Single-Wall
SP23, SP33
1.5”
SP45, SP69, SP150
2”
Double-Wall
SPDW23, SPDW32
1.5”
SPDW42, SPDW61, SPDW113
2”
In addition to the heat exchanger and piping components, each SmartPlate Piping Assembly
contains a number of other important components and assemblies. The items include:
•Mixing box
•Recirculation Pump, (Continuously ON)
•Isolation & Drain Valves
•Strainers (Boiler Water & DHW Sides)
•Blow-down Valves
•Relief Valve
•Air Vent Valve
Figure 1-3 illustrates the locations of the above-mentioned items for a single-wall heat
exchanger. Piping components are similar for double-wall models.
1.4 ELECTRONIC CONTROL VALVE, MXG-461
The 3-Way Electronic Control Valve (Siemens MXG-461) is powered by 24 VAC which is
received from the ECS/SP Control Box. The Temperature Controller in the Control Box supplies
a 0 –10 VDC control signal to precisely modulate the 3-Way Valve to accurately control the
temperature of the DHW output to the desired setpoint. The Control Valve is shown in Figure 1-
4. The connection unions have flat face gaskets that provide the fluid seal.

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Figure 1-3. Typical SmartPlate Piping Assembly –2” Piping Shown
ELECTRONICS
MODULE
PORT A
PORT B
PORT AB
HANDWHEEL
VALVE
BODY
Figure 1-4. Electronic Control Valve
RELIEF VALVE
ISOLATION
BALL VALVE
(4 PLCS)
BOILER WATER
DIFFERENTIAL
PRESSURE GAUGE
DRAIN VALVE
RECIRCULATION PUMP
STRAINERS WITH BLOWDOWN VALVES
INTAKE
MIXING BOX
BOILER WATER INLET
DHW OUTLET
COLD WATER
INLET
BOILER WATER
OUTLET
HEAT
EXCHANGER
3-WAY CONTROL
VALVE
AIR VENT
VALVE

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INSTALLATION
2.1 INTRODUCTION
All of the SmartPlate Water Heater models are shipped fully assembled and ready for
installation. Therefore, installation will consist of the following tasks:
•Unpack the SmartPlate Water Heater from its shipping container.
•Position and secure the unit at the site.
•Install the Relief Valve and Air Vent Valve on the mixing box.
•On units installed in New York City, install a second Relief Valve on the boiler water intake
piping.
•Connect the hot boiler water piping to the unit.
•Connect the domestic hot water (DHW) piping to the unit.
•Connect external AC power to the ECS/SP Control Box.
•If required, connect Modbus control wiring to the Temperature Controller in the ECS/SP
Control Box.
2.2 RECEIVING AND UNPACKING SMARTPLATE
Each SmartPlate Water Heater is shipped as a single crated unit. The packaged shipping
weight will vary from 380 to approximately 1100 pounds depending on the model ordered. The
unit must be moved with the proper equipment (forklift, pallet jack, etc.) to avoid possible injury
to personnel or damage to the shipping container or unit. The shipping carton should be
inspected for damage incurred during transit prior to signing the bill of lading.
NOTE:
AERCO is not responsible for lost or damaged freight. The freight carrier must be notified
immediately of any damage detected.
Unpack the SmartPlate Water Heater from its shipping container taking care not to damage the
unit when cutting away the packaging material.
Remove the package containing the Relief Valve and Air Vent Valves. This package may also
contain an additional Relief Valve. See section 2.6 for a complete list of parts and installation
instructions.
Remove the bolts securing the unit to its shipping skid. Perform a complete visual inspection of
the unit to ensure there is no evidence of damage.

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2.3 SITE SELECTION AND PREPARATION
Ensure that the site selected for installation of the SmartPlate Water Heater includes the
following:
•Access to AC input power at 120 VAC/60 Hz, 220 VAC/50 Hz or 220 VAC 60 Hz, single
phase.
•Close proximity to the boiler to be used as the heating fluid (hot water) source
•If applicable; access to Modbus Network wiring within the prescribed wire lengths (see
section 2.5.
2.3.1 INSTALLATION CLEARANCES
The heater must be installed with the prescribed clearances for service as shown in Figure 2-1.
the minimum clearance dimensions recommended by AERCO are listed below. However, if
local building codes require additional clearances, these codes shall supersede AERCO’s
recommendations.
•Sides: 24 in. (61 cm)
•Front: 24 in. (61 cm)
•Rear: 24 in. (61 cm)
•Top: 12 in. (30.5 cm)
All water piping and electrical conduit must be arranged so that it does not interfere with the
removal of any Water Heater assemblies/parts or inhibit service or maintenance of the unit.
Figure 2-1. SmartPlate Water Heater Clearances
CAUTION!
While packaged in the shipping container, the heater must be move using a forklift or pallet
jack. After unpacking, the heater should be lifted and moved using the lifting tabs (single-wall
model), or frame cutouts (double-wall model) provided on the heater. Alternately, a forklift or
pallet jack may be used to move the unit by inserting the tines through the cutouts in the
heater base (Figure 2-1). Refer to the information in the following section.

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2.3.2 SETTING THE UNIT
SmartPlate Single-Wall models contain two lifting tabs at the top of the frame assembly (Figure
2-2 a). Use these tabs to lift and move the unit. Double-Wall models contain two round cutouts
on the frame plate and two on the pressure plate of the heat exchanger (Figure 2-2 b). To lift
and move the unit, use these cutouts, or wrap the lifting strap around the threaded bolts
protruding from the heat exchanger (Figure 2-2 b).
In multiple unit installations, it is important to plan the position of each unit in advance. Sufficient
space for piping connections and future service/maintenance requirements must also be taken
into consideration. All piping must include ample provisions for expansion.
Figure 2-2 a. SmartPlate Lifting Provisions –Single-Wall Models
CAUTION!
For Single-Wall models, DO NOT attempt to reposition the ECS/SP Control Box with the
panel displays facing the unit’s Piping Assembly, as the location of the lifting tabs will prevent
the Control Box door from opening fully (Figure 2-2 a).
ECS/SP
CONTROL BOX
LIFTING TABS
CONTROL
VALVE

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Figure 2-2 b. SmartPlate Lifting Provisions –Double-Wall Models
2.3.3 REPOSITIONING ECS/SP CONTROL BOX
If required, the front panel displays of the ECS/SP Control Box can be repositioned from the
default left-side of the unit (Figure 2-2) to either the right side or rear of the unit to optimize
viewing of the panel displays. Repositioning of the Control Box is accomplished as follows:
REPOSITIONING ECS/SP CONTROL BOX Instructions
1. Power the unit off.
2. Disconnect external cables at their respective connections (Molex).
3. From the rear of the unit (Figure 2-3, below), remove the four Phillips head screws
securing the base of the Control Box to the unit’s frame assembly.
4. Position the Control Box to the desired orientation to provide easy viewing of the control
panel displays.
5. Ensure that all power and control wiring are of sufficient length to prevent undue stress on
the wiring connections. Reposition wiring harnesses as necessary.
6. Replace the four Phillips head screws removed in step 1.
7. Apply power if previously connected.
8. This completes the repositioning of the ECS/SP Control Box.
PRESSURE
PLATE
CUTOUTS
FRAME
CUTOUTS

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REPOSITIONING ECS/SP CONTROL BOX Instructions
SMARTPLATE –PARTIAL REAR VIEW
ECS/SP
CONTROL
BOX
SUPPORT
FRAME
HEAT
EXCHANGER
(SINGLE-WALL)
PHILLIPS HD.
SCREWS
(4 PLCS)
Figure 2-3. Repositioning ECS/SP Control Box
2.4 HEATING FLUID AND DOMESTIC HOT WATER (DHW) PIPING
The diameter of the heating fluid (hot boiler water) and DHW piping will depend on the model
number and size of the unit being installed. Refer to Table 2-1 for applicable piping sizes.
TABLE 2-1. Pipe Sizing Chart
Type
SmartPlate Water Heater Model
Pipe Diameter
Single-Wall
SP23, SP33
1.5 inches
SP45, SP69, SP150
2.0 inches
Double-Wall
SPDW23, SPDW32
1.5 inches
SPDW42, SPDW61, SPDW113
2.0 inches
CAUTION!
Two pipe wrenches MUST be used when installing boiler water and DHW piping unions to
prevent pipe rotation and avoid leaks.
The locations and spacing for the heating fluid (hot boiler water) and DHW piping are provided
in Dimensional Drawings AP-A-846 (Single-Wall) and AP-A-847 (Double-Wall), included in
Appendix D of this document. In addition, sample piping diagrams are provided in Appendix C
for single and multiple unit installations.

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IMPORTANT!
When SmartPlate Water Heaters are shipped from the factory, all four isolation ball valves
and the drain valve (Figure 1-3) are opened. Close all valves during installation. Do not open
the valves until instructed to do so in Chapter 5 of this manual.
2.5 SMARTPLATE ELECTRICAL WIRING CONNECTIONS
The SmartPlate ECS/SP Control Box and all other ECS/SP components are installed on the unit
prior to shipment from the factory. Therefore, electrical connections to the ECS/SP basically
consist of connecting external AC power to the ECS/SP Control Box. The system can be
powered by a single-phase AC voltage of 120 VAC, 60 Hz, 220 VAC, 50 Hz or 220 VAC 60 Hz.
However, if the ECS/SP was ordered with the Modbus Communication option, several additional
signal lead connections will need to be made inside the Control Box. These signal leads will
permit the ECS/SP to be controlled by an external Energy Management System (EMS), Building
Automation System (BAS), or Computer. Proceed as follows:
NOTE:
Following installation, a lock (Not Supplied) can be installed on the front door of the Control
Box, if desired, to prevent unauthorized access to ECS settings.
ELECTRICAL WIRING CONNECTIONS Instructions
1. Loosen the captive screw on the right-front portion of the Control Box (Figure 2-4) to open
the hinged panel door.
Figure 2-4. ECS/SP Control Box Front View
2. Next, open the door and loosen the captive screw at the top of the recessed panel (Figure
2-5).
PANEL DOOR
CAPTIVE
SCREW
HOLE FOR
LOCK

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ELECTRICAL WIRING CONNECTIONS Instructions
Figure 2-5. Recessed Panel Behind ECS/SP Control Box Door
3. Swing down the recessed panel to access Terminal Block TB-2 on the bottom interior
surface of the Control Box, shown in Figure 2-6.
NOTE:
Use 14 to 18 AWG wire for AC power wiring connections to the SmartPlate ECS/SP Control
Box.
4. Feed the external 120/220 VAC power leads through the cutout labeled “POWER IN” on
the bottom of the Control Box.
5. Connect the LINE, NEUTRAL and GROUND leads to the TB-2 terminals shown in Figure
2-6.
6. Check the connection of wire #100 on the right side of TB-2 to ensure the power is routed
to the proper connection for the 24 VAC transformer. If the incoming power is 120 VAC,
wire #100 should be connected to the terminal with a black wire and the orange wire
should have nothing connected to its terminal. Conversely, if the incoming power is 220
VAC, wire #100 should be connected to the terminal with the orange wire and the black
wire left unconnected.
PANEL CAPTIVE
SCREW

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ELECTRICAL WIRING CONNECTIONS Instructions
INTERIOR BOTTOM SURFACE
REAR
TB-2
GND
LINE
NEUTRAL
GND
INSTALL EXTERNAL POWER
WIRING THROUGH THIS
CUT-OUT
WHITE
TO
TRANSFORMER
BLACK
ORANGE
220/24 VAC
120/24 VAC
101
GND
POWER
SWITCH
100
102
102
100F
FROM
FUSE
FOR 220 VAC, WIRE #100
MUST BE CONNECTED
TO THIS TERMINAL
Figure 2-6. ECS/SP Control Box AC Power Connections

SmartPlate Installation, Operation & Maintenance Manual
CHAPTER 2 –INSTALLATION
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ELECTRICAL WIRING CONNECTIONS Instructions
Figure 2-7: Remote Relay Option Kit (P/N 69018) Schematic
7. If the ECS was ordered with the Modbus Communication Option, proceed to step 8.
However, if this option is not included, no further steps are required. In that case, re-secure
the hinged swing-down panel of the Control Box and close the front panel door.
NOTE:
Step 8 applies ONLY to SmartPlate Control Systems that include a Temperature Controller
(Eurotherm, model 2408) equipped with a Communications Board that allows connection to
Modbus Networks. The required signal connections will depend on the ports available on
the Energy Management System (EMS), Building Automation System (BAS), or Computer
being used with the ECS/SP.
CAUTION!
DO NOT route Modbus communication wiring in the same conduit as power wiring.
Attempting to do so may result in excessive noise on the signal lines. Also, ensure that the
RS232 or RS485 signal cable connections do not exceed the following lengths:
•RS232 Cable: 50 feet maximum
•RS485 Cable: 4,000 feet maximum
NO NC
OVER-TEMPERATURE
FAULT RELAY
Rated for 2 amps, 260VAC
(Energized Upon Fault)

SmartPlate Installation, Operation & Maintenance Manual
CHAPTER 2 –INSTALLATION
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ELECTRICAL WIRING CONNECTIONS Instructions
8. To permit Modbus control of the ECS/SP, refer to Table 2-2, below, and connect the
appropriate wire leads to the Temperature Controller terminals listed. Refer to the
Temperature Controller (Eurotherm 2408) pinouts shown in Figure 2-8 to locate the
required terminals. Also, refer to Appendix A for instructions on how to change the
Temperature Controller Modbus address and for a listing of active Modbus data addresses
for the 2408 Controller. In addition, the Eurotherm documents referenced in this Appendix
provide additional communication information related to Modbus.
NOTE:
The complete wiring diagram for the SmartPlate Electronic Control System is provided in
Appendix B of this Instruction Manual. In addition, the wiring connections for Control Box
Terminal Blocks TB-1 and TB-2 are also provided for reference purposes.
NOTE:
AERCO recommends that shielded, twisted-pair cable be used for communication wiring.
Examples of suitable wiring are: Belden 9841, 8761, 3105A, or equivalent.
TABLE 2-2. Modbus Communication Signal Connections
2408 TEMP. CONTROLLER
COMPUTER CONTROL CABLE
RS232/9-PIN
RS232/25-PIN
RS485
SIGNAL NAME
PIN NO.
SIGNAL NAME
PIN NO.
PIN NO.
PIN NO.
GROUND
HD
GROUND
5
7
GROUND
RECEIVE
HE
TRANSMIT
3
2
A(-)
TRANSMIT
HF
RECEIVE
2
3
B(+)
1A HA
1B HB
1C HC
2A
2B
1D HE
HF
HD
3B
3D
3C
2D
3A
2C
JD
JF
JE
JB
JC
JA
LA
LB
LC
AA
AB
AC
VI
V+
V-
In1
In2
C
2408 CONTROLLER
L
N
SEE TABLE 2-2 FOR COMM CONNECTIONS
Figure 2-8. Temperature Controller (Eurotherm 2408) Terminal Connection Diagram