heat-timer SMC Owner's manual

HT# 059115-00 B
Installers and Users Installation
and Operation Manuals
Operates a Modulating Motorized Valve, a
Modulating Boiler, or Multi-Boiler Control
With Optional BACnet Communication
SMC
WARNING
This Heat-Timer control is strictly an operating control; it should never
be used as a primary limit or safety control. All equipment must have its
own certified limit and safety controls required by local codes. The installer
must verify proper operation and correct any safety problems prior to the
installation of this Heat-Timer control.
Snowmelt Control

2SMC Installation and Operation Manual
HT# 059115-00 B
SMC Function Chart . . . . . . . . . . . . . . . 3
 . . . . . . . . . . . . . . . . . . . . . 4
SMC Operation Modes . . . . . . . . . . . . . . 4
Slab Sensor Operation Overview . . . . . . . . . 4
Typical Slab Sensor Mode Installation Steps . . 5
Typical Outdoor Mode Installation Steps . . . . 7
 . . . 8
Installation . . . . . . . . . . . . . . . . . . . . . 9
Mounting the Enclosure. . . . . . . . . . . . . . 9
Sensor Installation. . . . . . . . . . . . . . . . . 10
Slab Sensor Installation . . . . . . . . . . . . . . . 10
Outdoor Sensor Installation . . . . . . . . . . . . . 11
Water Temperature Sensor Installation . . . . . . . 11
Wiring the Power. . . . . . . . . . . . . . . . . . 12
Output Wiring . . . . . . . . . . . . . . . . . . .12
Wiring System Pump and Slab Pump . . . . . . . . 12
Wiring To a Floating Motorized Valve . . . . . . . . 13
Wiring To a Modulating Motorized Valve . . . . . . .13
Wiring To an On/Off Boiler. . . . . . . . . . . . . .14
Wiring To a Modulating Boiler . . . . . . . . . . . . 14
Wiring Alarm output to Visual/Audio Alarm . . . . . . 14
Wiring Alarm Output to BMS. . . . . . . . . . . . .15
Wiring to 4-20mA Remote Set Point . . . . . . . . .15
Input Wiring . . . . . . . . . . . . . . . . . . . .15
Wiring the Slab Sensor . . . . . . . . . . . . . . . 15
Wiring the Outdoor Sensor . . . . . . . . . . . . . 16
Wiring the Boiler Return Sensor . . . . . . . . . . . 16
Wiring the Slab Supply and Return Sensors . . . . . 16
Wiring the Shutdown / Enable . . . . . . . . . . . . 17
Wiring the Prove . . . . . . . . . . . . . . . . . . 17
Wiring to BACnet MSTP . . . . . . . . . . . . . .18
Activate the Battery . . . . . . . . . . . . . . .18
Display and Buttons . . . . . . . . . . . . . . .19
Setting the Control to Factory Defaults. . . . 19
Display Messages . . . . . . . . . . . . . . . . 20
System Startup Menus. . . . . . . . . . . . . .21
System Startup. . . . . . . . . . . . . . . . . . . 22
Program Switch Setting . . . . . . . . . . . . . . . 22
Sensor Type . . . . . . . . . . . . . . . . . . . . 22
Control Mode . . . . . . . . . . . . . . . . . . . . 22
External Input . . . . . . . . . . . . . . . . . . . . 22
Display Unit . . . . . . . . . . . . . . . . . . . . . 23
Ignition Start . . . . . . . . . . . . . . . . . . . . 23
EMS 4mA and 20mA Set Point . . . . . . . . . . . 23
Set Present Time . . . . . . . . . . . . . . . . . . 23
BACnet Communication . . . . . . . . . . . . . 24
BACnet Option . . . . . . . . . . . . . . . . . . . 24
BACnet MSTP Settings . . . . . . . . . . . . . . 24
BACnet Baud . . . . . . . . . . . . . . . . . . . . 24
BACnet Address . . . . . . . . . . . . . . . . . . 24
BACnet ID . . . . . . . . . . . . . . . . . . . . . 24
Operating Menus . . . . . . . . . . . . . . . . . 25
Operating Settings. . . . . . . . . . . . . . . . . 25
Program Switch Setting . . . . . . . . . . . . . . . 25
Season . . . . . . . . . . . . . . . . . . . . . . . 26
Warm Weather Cutoff (WWC) . . . . . . . . . . . .26
Idle Set Point (ISP) . . . . . . . . . . . . . . . . . 26
Heating Curve . . . . . . . . . . . . . . . . . . . 26
Heating Curve Table . . . . . . . . . . . . . . . . 27
System Settings . . . . . . . . . . . . . . . . . . 28
Cold Weather Cutoff (CWC) . . . . . . . . . . . . .28
Heating Gain . . . . . . . . . . . . . . . . . . . . 28
Minimum Runtime. . . . . . . . . . . . . . . . . . 28
Maximum Delta Temperature (Max ∆T) . . . . . . . 29
Maximum Slab Supply . . . . . . . . . . . . . . . 29
Minimum Boiler Return . . . . . . . . . . . . . . . 29
Pump Settings . . . . . . . . . . . . . . . . . . . 29
Run-On . . . . . . . . . . . . . . . . . . . . . . . 29
Pump Exercise . . . . . . . . . . . . . . . . . . . 30
Antifreeze. . . . . . . . . . . . . . . . . . . . . . 30
Maintenance Menu . . . . . . . . . . . . . . . . 31
Maintenance Settings . . . . . . . . . . . . . . . 31
Program Switch Setting . . . . . . . . . . . . . . . 31
Display Unit . . . . . . . . . . . . . . . . . . . . . 31
Set Present Time . . . . . . . . . . . . . . . . . . 31
Boiler Runtime . . . . . . . . . . . . . . . . . . . 32
Sensors Trim . . . . . . . . . . . . . . . . . . . . 32
Water Sensitivity . . . . . . . . . . . . . . . . . . 32
History . . . . . . . . . . . . . . . . . . . . . . . 32
Conguration . . . . . . . . . . . . . . . . . . . . 32
User Menus . . . . . . . . . . . . . . . . . . . . 33
User Settings. . . . . . . . . . . . . . . . . . . . 33
Program Switch Setting . . . . . . . . . . . . . . . 33
Season . . . . . . . . . . . . . . . . . . . . . . . 33
Warm Weather Cutoff (WWC) . . . . . . . . . . . .33
Cold Weather Cutoff (CWC) . . . . . . . . . . . . .34
Idle Set Point (ISP) . . . . . . . . . . . . . . . . . 34
Heating Curve . . . . . . . . . . . . . . . . . . . 34
Heating Gain . . . . . . . . . . . . . . . . . . . . 35
Minimum Runtime. . . . . . . . . . . . . . . . . . 35
Alarms Menu. . . . . . . . . . . . . . . . . . . . 36
Alarm . . . . . . . . . . . . . . . . . . . . . . . . 36
Alarm List . . . . . . . . . . . . . . . . . . . . . 36
BACnet Variable List . . . . . . . . . . . . . . . 37
BACnet PICS Statement . . . . . . . . . . . . .38
Troubleshooting. . . . . . . . . . . . . . . . . . 39
Warranty . . . . . . . . . . . . . . . . . . . . . . 41
Slab Sensor Diagrams . . . . . . . . . . . . . . 42
SMC Controlling a Modulating Water Boiler - Piping . 42
SMC Controlling a Modulating Water Boiler - Wiring 43
SMC Modulating a 3-Way Motorized Valve - Piping . 44
SMC Modulating a 3-Way Motorized Valve - Wiring . 45
SMC Modulating a 3-Way Motorized Valve - Piping . 46
SMC Modulating a 3-Way Motorized Valve - Wiring . 47
SMC Modulating a 2-Way Motorized Valve - Piping . 48
SMC Modulating a 2-Way Motorized Valve - Wiring . 49
SMC Controlling Multi-Boiler Control - Piping . . . . 50
SMC Controlling Multi-Boiler Control - Wiring . . . . 51
 . . . . . . . . . . . . . . . . . . . 52
SMC Specications . . . . . . . . . . . . . . . . . 52
Slab Sensor Specications: . . . . . . . . . . . . . 52
CONTENT

SMC Installation and Operation Manual 3
HT# 059115-00 B
SMC FUNCTION CHART
PWR SYSTEM
PUMP
OR VALVE
BURNER
SLAB
PUMP ALARM
SLAB
VALVE
CLOSE OPEN
SLAB
SUPPLY
TEMP
SLAB
RETURN
TEMP
BOILER
RETURN
TEMP
SHUTDOWN
/ENABLE
PROVE
RS485
SLAB TEMP/OUT
(BROWN)
SENSOR COM
(BLUE)
HEATER TEMP
(WHITE)
WATER DETECT
(GREEN)
HEATER PWR
(RED)
HEATER COM
(BLACK)
16 17 18 19 20 214 5 6 7 8 9 10 11 12 13 14 151 2 3 22 23 24 25 26 27 28 29 30 31 32 33 34 35
PROGRAM RUN
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
L N G
ACTIVE OUTPUTS
SYSTEM
BURNER
SLAB PUMP
ALARM
VALVE CLOSE
VALVE OPEN
POWER
SMC
SNOW MELT CONROL
OUTPUT RATINGS: 6A RESISTIVE, 120VAC
MAXIMUM 15A TOTAL FOR ALL CIRCUITS
INPUT RATINGS: 120 VAC 60 Hz, 48VA MAX.
CAUTION: Risk of Electric Shock.
Use Copper Conductors Only.
0-10V
OUTPUT
4-20mA
OUTPUT
V+ - mA -
ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
ALARM MENU
SLAB SUP 120o
rtn 102o
38oF
__________________________
Melting in Progress
Boiler Return = 142
o
F
The digital display shows the Slab or Outdoor,
Supply, and Return temperatures in addition to
Boiler Status and its return temperature.
120VAC
Power
Output relays to operate
boiler, slab pump, alarm, and
modulating valve.
System Output operates
the system pump or valve.
Slab or
Outdoor Sensor
LED indicates the associated
output relay status.
Button functions are presented on
Bottom Row of display.
Temperature and
Dry-contact inputs.
Program Switch to restrict access to
function changes. This switch is
covered with Wiring Enclosure.
Connect to
BACnet Interface
Module
Boiler or Motorized Valve
modulation output signal or 4-20mA
Ext. Interface Set Point.

4SMC Installation and Operation Manual
HT# 059115-00 B
DEFINITIONS
WARNING Warns of possible exposure to risk which can cause personal injury or property
damage if ignored.
ALERT Attention is required to avoid wrong control operation or restricted access to some
settings.
WWC Warm Weather Cutoff. See "Warm Weather Cutoff (WWC)" on page 26.
ISP Idle Set Point. See "Idle Set Point (ISP)" on page 26.
CWC Cold Weather Cutoff. See "Cold Weather Cutoff (CWC)" on page 28.
 The Slab Delta T is the difference in temperature between the Slab Supply temperature
and the Slab Return temperature.
SMC OPERATION MODES
The Snowmelt Control (SMC) is designed to operate a radiant slab Hydronic heating system to prevent snow
and ice accumulation on sidewalks, driveways, and other areas where buildup is undesirable. It does this
using the provided Slab Sensor. This is the Heat-Timer preferred operation mode.
ALERT
In Slab Sensor Type mode, the slab sensor base and its conduit must be installed before the slab installation.
However, in some sites where the concrete slab is old and cannot be altered, the SMC can operate based
on the Outdoor Sensor using the Outdoor Sensor Type mode. This method does not provide any moisture
detection and requires the purchase of the optional Outdoor Sensor (HT# 904220-00).
SLAB SENSOR OPERATION OVERVIEW
The SMC uses the Slab Sensor in two steps. First, the SMC continuously monitors the slab temperature
and detects moisture. When the SMC starts the Idle mode, it will try to maintain the slab temperature above
freezing. Second, when it detects moisture and the temperature suggests possible ice or snow accumulation,
the SMC activates the heating system to evaporate the moisture by raising the supply temperature.
The Slab Sensor provides the slab temperature and moisture information necessary to run the slab heating
system. This Brass sensor is designed to become an integral part of the slab. Therefore, it is specically
engineered to support extreme heat and cold temperatures and to withstand pressure and impact, such
as might occur when a car drives over it. Despite its sturdy structure, the sensor is very accurate. Its
temperature accuracy is within one degree and its moisture sensitivity is adjustable to sense even traces
of precipitation. The Slab Sensor does not allow any snow or ice accumulation. It does this using a built-in
heater that operates below freezing temperatures.
A snowmelt system generally includes a heating plant and a slab pump to move the water/anti-freeze solution
through the slab's radiant piping. Whenever the Slab Sensor reads a temperature below the adjustable
WWC, the SMC enables the Idle mode. In Idle mode the SMC maintains the slab temperature above freezing
(at the ISP). It does this by pulsing the Slab Pump (15 seconds for every Antifreeze period) when the slab
temperature is above the ISP. See "Antifreeze" on page 30. When the slab temperature drops below the ISP,
the SMC activates the heating plant Slab and System Pumps to maintain the slab at the ISP temperature.
This gives the slab a head start on melting should precipitation occur.
Once the slab heating system is activated, the amount of energy entering the slab is determined by the
difference between the temperature of the uid going to the slab (the Slab Supply temperature) and the
temperature of the uid returning from the slab (the Slab Return temperature). The difference between these
two is called the Slab ΔT. The Slab ΔT is different for each slab composition based on the slab design. The
higher the Slab ΔT, the more energy is being input to the slab. If the Slab ΔT is set larger than its design ΔT
(Max ΔT), the slab itself may be damaged. The SMC provides a maximum Slab ΔT adjustment. This setting
protects the slab during the initial warm-up periods. See "Maximum Delta Temperature (Max ∆T)" on page 29.

SMC Installation and Operation Manual 5
HT# 059115-00 B
The slab must be kept above freezing whenever there could be frozen precipitation. As a result, any ice or
snow that falls on the slab will melt immediately. If precipitation is allowed to accumulate before heating the
slab, an effect called bridging can occur. The snow or ice directly in contact with the slab will melt. But, the
snow above will act as an insulator, reecting the heat back into the slab. The slab itself will have no ice
touching its surface, but the remaining accumulation will melt very slowly. To prevent this, the SMC activates
the slab heating system whenever the slab temperature falls below the adjustable WWC setting.
On a further drop in slab temperature below the CWC, the control is said to be in CWC Mode. In this mode
the SMC stops its heating process. It does this by de-energizing the boiler and System Pump and closing
the motorized valve. In addition, it pulses the Slab Pump to prevent the slab and its radiant solution from
freezing. See "Antifreeze" on page 30.
The SMC includes several additional features that can be used to protect the plant and slab. The SMC
can be used with a Boiler Return Sensor to help reduce boiler thermal shock possibility. Additionally, it is
equipped with an Alarm output. This alarm is activated when any sensor fails to read correctly or if the slab
was not receiving sufcient heat.
Warm Weather
Cutoff (WWC)
Idle Set Point (ISP)
Cold Weather
Cutoff (CWC)
Moisture
Not Detected
Slab Target = Off
Boiler = Off
Valve = Close
Slab Pump = Pulse to even slab temp.
System Pump = Off
Slab Target = ISP
Boiler = On
Valve = Modulating
Slab Pump = On
System Pump = On
Slab Target = Off
Boiler = Off
Valve = Close
Slab Pump = Pulse to eliminate freezing
System Pump = Off
Slab Temperature
38°F
Slab Target = Off
Boiler = Off
Valve = Close
Slab Pump = Off
System Pump = Off
34°F
10°F
Control
is in CWC
Control
is in WWC
Control
is Idling
Control
is Idling
Warm Weather
Cutoff (WWC)
Idle Set
Point (ISP)
Cold Weather
Cutoff (CWC)
Moisture
Detected
Slab Target = Off
Boiler = Off
Valve = Close
Slab Pump = Pulse to eliminate freezing
System Pump = Off
Slab Temperature
38°F
34°F
10°F
Control
is in CWC
Control
is in WWC
Slab Target = WWC
Boiler = On
Valve = Modulating
Slab Pump = On
System Pump = On
Slab Target = WWC
Boiler = On
Valve = Modulating
Slab Pump = On
System Pump = On
Control
is Melting
Until Precipitation
is dry
TYPICAL SLAB SENSOR MODE INSTALLATION STEPS
To install and set the control to operate based on the Slab Sensor follow these steps:
• Install the Slab Sensor Base, Dummy Plastic Plug, and conduit before the slab concrete pour. See "Slab
Sensor Installation" on page 10.
• Install the SMC control indoors. See "Mounting the Enclosure" on page 9.
• Install and wire the Slab Supply, Slab Return, and the optional Boiler Return Sensor in their wells. See
"Water Temperature Sensor Installation" on page 11.
• After the concrete pour and slab installation, replace the Dummy Plastic Plug with the Slab Sensor, making
sure to run the cable through the conduit.
• Wire the power to the SMC. But do not power it. See "Wiring the Power" on page 12.
• Wire the SMC outputs to the System and Slab Pumps, Motorized Valve, and Boiler. See "Output Wiring" on
page 12.
• Power the SMC.

6SMC Installation and Operation Manual
HT# 059115-00 B
• Set the following SMC System Startup settings:
○ Sensor Type = Slab. See "Sensor Type" on page 22.
○ Control Mode = Select "Motorized Valve" if the slab loop is using a 2-way steam motorized
valve (and a heat-exchanger) or a 3-way hydronic mixing motorized valve.
= Select "Boiler" if the slab loop is heated directly by a modulating boiler.
= Select "Ext. Interface" if the SMC is connected to a Heat-Timer multi-boiler
control (Multi-MOD Platinum, Mini-MOD, SQ-Elite, etc..). Then set the
EMS 4 and 20mA set points to match the boiler control 4-20mA set points.
See "Control Mode" on page 22.
• Suggested starting point for SMC Operating settings:
○ WWC = 38°F. See "Warm Weather Cutoff (WWC)" on page 26.
○ CWC = 10°F or as per engineers criteria. See "Cold Weather Cutoff (CWC)" on
page 28.
○ ISP = 34°F or as per engineers criteria. See "Idle Set Point (ISP)" on page 26.
○ Maximum Delta T = As per engineers criteria. See "Maximum Delta Temperature (Max ∆T)" on
page 29.
○ Maximum Slab Supply = As per slab design engineer. See "Maximum Slab Supply" on page 29.
○ Minimum Boiler Return = As per boiler manufacturer specications. See "Minimum Boiler
Return" on page 29.
○ Season = Winter. See "Season" on page 26.
WARNING
Heat-Timer recommends installing a high-limit control to shutdown the
heating system in case of excessive high slab supply temperatures.
OUTDOOR SENSOR OPERATION OVERVIEW
The Snowmelt Control (SMC) is designed to control under slab
heating systems to prevent accumulations of ice or snow. Heat-
Timer recommends that the Slab Sensor be utilized, but the SMC
can be used with an Outdoor Sensor instead in situations where
a Slab Sensor installation is difcult. In the Outdoor Sensor
Type mode, the SMC monitors three temperatures, the outside
temperature, the temperature of the uid going to the slab (Slab
Supply temperature), and the temperature of the uid returning
from the slab (Slab return temperature).
The slab must be kept above freezing whenever there could be
frozen precipitation. As a result, any ice or snow that falls on the
slab will melt immediately. If precipitation is allowed to accumulate
before heating the slab, an effect called bridging can occur. The
snow or ice directly in contact with the slab will melt. But, the
snow above will act as an insulator, reecting the heat back into
the slab. The slab itself will have no ice touching its surface, but
the remaining accumulation will melt very slowly. To prevent this,
the SMC activates the slab heating system whenever the outside
temperature falls below the adjustable WWC setting.
Once the slab heating system is activated, the amount of energy
entering the slab is determined by the difference between the
temperature of the uid going to the slab (the Slab Supply) and the
temperature of the uid returning from the slab (the Slab Return).
Warm Weather
Cutoff (WWC)
Cold Weather
Cutoff (CWC)
No Moisture
Detection Available
Slab Return Target = On
Boiler = On
Valve = Modulating
Slab Pump = On
System Pump = On
Slab Target = Off
Boiler = Off
Valve = Close
Slab Pump = Pulse
System Pump = Off
Outdoor Temperature
38°F
Slab Target = Off
Boiler = Off
Valve = Close
Slab Pump = Off
System Pump = Off
10°F
Control
is Melting
Control
is in CWC
Control
is in WWC

SMC Installation and Operation Manual 7
HT# 059115-00 B
The difference between these two is called the Slab ΔT. The Slab ΔT is different for each slab composition
based on the slab design. The higher the Slab ΔT, the more energy is being input to the slab. If the Slab ΔT
is set larger than its design ΔT (Max ΔT), the slab itself may be damaged. The SMC provides a Maximum
Slab ΔT adjustment. This setting protects the slab during the initial warm-up periods. See "Maximum Delta
Temperature (Max ∆T)" on page 29.
After the warm-up period, each slab has a heat loss that varies with the outdoor temperature changes.
Therefore, a slab might require 130°F uid temperature at 0°F outdoor temperature to maintain its heat.
However, when the outdoor warms to 15°F, it might require only 100°F uid temperature circulating. The
SMC has a Heating Curve adjustment to insure the slab temperature is sufciently warm to melt frozen
precipitation once the warm-up period has ended. The curve value compensates for the different slab types
and different outdoor weather conditions. After making a change in the Heating Curve value, it is necessary
to wait at least four hours before assessing the effect it had on slab temperature. See "Heating Curve" on
page 26.
TYPICAL OUTDOOR MODE INSTALLATION STEPS
To install and set the control to operate based on the Outdoor Sensor follow these steps:
• Install the SMC control indoors. See "Mounting the Enclosure" on page 9.
• Install and wire the Slab Supply, Slab Return, and the optional Boiler Return Sensor in their wells. See
"Water Temperature Sensor Installation" on page 11.
• Install and wire the Outdoor Sensor. See "Outdoor Sensor Installation" on page 11.
• Wire the power to the SMC. But do not turn on circuit breaker. See "Wiring the Power" on page 12..
• Wire the SMC outputs to the System and Slab Pumps, Motorized Valve, and Boiler. See "Output Wiring"
on page 12.
• Power the SMC.
• Set the following SMC System Startup settings:
○ Sensor Type = Outdoor. See "Sensor Type" on page 22.
○ Control Mode = Select Motorized Valve if the slab loop is using a 2-way or 3-way
motorized valve.
Select Boiler if the slab loop is heated directly by a modulating boiler.
Select Ext. Interface if the SMC is connected to a multi-boiler control
(Multi-MOD Platinum, Mini-MOD, SQ-Elite, etc..). Then set the EMS
4mA and 20mA set points to match the multi boiler control 4-20mA set
points. See "Control Mode" on page 22.
• As a starting point the following SMC Operating settings needs to be set:
○ WWC = 38°F . See "Warm Weather Cutoff (WWC)" on page 26.
○ CWC = 10°F or as per engineers criteria. See "Cold Weather Cutoff (CWC)" on
page 28.
○ Maximum Delta T = As per slab design engineer. See "Maximum Delta Temperature (Max
∆T)" on page 29.
○ Maximum Slab Supply = As per slab design engineer . See "Maximum Slab Supply" on page 29.
○ Minimum Boiler Return = As per boiler manufacturer specications. See "Minimum Boiler Return"
on page 29.
○ Season = Winter. See "Season" on page 26.

8SMC Installation and Operation Manual
HT# 059115-00 B
TYPICAL SNOWMELT PIPING CONFIGURATION
The SMC can regulate the temperature of the anti-freeze/water solution to the slab by one of the following
methods:
• Modulate a condensing boiler using voltage or current modulating signal. See "SMC Controlling a
Modulating Water Boiler - Piping" on page 42. In this scenario set the following startup settings:
○ Control Mode = Boiler
• Modulate a 3-way motorized valve (Floating, 0-10V, or 4-20mA signal) to mix the hot solution with solution
returning from the slab. The solution can be heated either directly using a condensing boiler or indirectly
using a heat-exchanger. See "SMC Modulating a 3-Way Motorized Valve - Piping" on page 44 and pg 46. In
this scenario set the following startup settings:
○ Control Mode = Motorized Valve
• Modulate a 2-way valve to control the amount of steam entering the steam-to-water heat-exchanger. The
temperature of the solution circulating the slab is controlled by a 2-way motorized valve installed on the
steam side of the heat-exchanger. See "SMC Modulating a 2-Way Motorized Valve - Piping" on page 48. In
this scenario set the following startup settings:
○ Control Mode = Motorized Valve
• Sending a 4-20mA set point to a multi-boiler sequencing control (Multi-MOD Platinum, Mini-MOD, SMC). In
this case , all boilers must be of the condensing type. See "SMC Controlling Multi-Boiler Control - Piping"
on page 50. In this scenario set the following startup settings:
○ Control Mode = Ext.Interface

SMC Installation and Operation Manual 9
HT# 059115-00 B
INSTALLATION
MOUNTING THE ENCLOSURE
The SMC consists of three primary enclosure
components.
  contains the control
electronic board, display, buttons, LEDs, and wiring
terminals. It has two screws to hold it to the base.
The Program/Run Switch is used to allow settings
adjustment. This switch is enclosed with the Enclosure
Wiring Cover for security. Wiring terminals are of the
plug-in type to ease installation and removal.
  contains the holes to mount and
hold the control against the wall or any at surface. All
other enclosure components mount on the base. The
bottom section of the Enclosure Base contains the
wiring chamber with knockouts on the bottom to ease
installation.
  seals the wires from
the external environment. It has two screws to hold it
to the base and a hole to secure a lock on the wiring
enclosure. A plastic web that separates the wiring
chamber into high and low volt sections has been
provided.
Enclosure Display Module
Enclosure Wiring Cover Enclosure Base
Hole for optional lock
(not supplied)
WARNING
Use only the provided Enclosure Knockouts. Do not
DRILL HOLES THROUGH THE ENCLOSURE, AS IT
WILL VOID CONTROL WARRANTY.
 Select a location near the equipment to be controlled.
 The surface should be at and sufciently wide and
strong to hold the SMC.
 Keep the control away from extreme heat, cold, or
humidity. The ambient operating temperature is from 20
to 120°F.
 Remove the Enclosure Wiring Cover from the control
enclosure by removing the two bottom screws.
 Remove the Enclosure Display Module by removing the
two middle screws.
 Screw the Enclosure Base to the surface through the
upper and lower mounting holes on the back of the
enclosure.
 Replace the Enclosure Display Module and replace the
two middle screws.
 Before operating the control, remove the battery's plastic
tab.
 Do not replace the Enclosure Wiring Cover until all wiring
is done.
 When purchasing a padlock for the enclosure, the
maximum shank diameter should not exceed ¼"
Mounting Holes
Display Mounting Screws
Wiring Cover
Mounting Screws

10 SMC Installation and Operation Manual
HT# 059115-00 B
SENSOR INSTALLATION
SLAB SENSOR INSTALLATION
(Used Only when Sensor Type is set to Slab)
• The supplied Slab Sensor is an integral part of the SMC
operation. It provides the SMC with the slab temperature
and detects precipitation. See "Slab Sensor Operation
Overview" on page 4.
• The Sensor consists of the following components:
○ The Brass Slab Sensor with 90 feet of cable
○ The Brass Sensor Base with a conduit hole
○ Dummy Plastic Plug (used to replace the slab sensor
during slab installation).
○ Brass mounting screws and O-ring.
• The Brass Slab sensor incorporates a slab temperature
sensor, a moisture detection sensor, a slab sensor heater,
and a sensor to measure the heater temperature.
• The slab temperature sensor measures the actual slab
temperature. The moisture detection sensor measures the
moisture connectivity of the precipitation. Both sensors are
used by the SMC snow melting logic.
• The slab sensor heater and its temperature sensor are
used to melt any precipitation that is in contact with the
Slab Sensor. However, its operation has no effect on the
slab temperature sensor or the control operation.
Slab Sensor
Sensor
Screws
O Ring
Slab
Sensor
Sensor
Base
Sensor
Cable
Conduit
Hole
Dummy
Plastic Plug
ALERT
The slab sensor base and its conduit must
be installed before the slab installation.
Slab Sensor Location Considerations
• When installed, the Slab Sensor must be level. Before the slab
installation, support the Sensor Base to level the Dummy Plastic Plug with
the nished grade.
• The Slab Sensor (HT #904200-00) should be placed in a location that
represents the temperature of the majority of the slab. It should be placed
away from any buildings, vents, or other heat sources. Also avoid placing
it in a sunny area when most of the slab is in shade, or vice versa.
• An exception to this later rule would be when the sensor location is
chosen to prevent snow or ice buildup in a known problem area.
• Run conduit from the sensor location to the panel to house the sensor
wires. This will ease servicing the sensor.
• If more than 90 feet of wire is needed to reach the control panel, install
a junction box along the way. (Up to 400 ft of 18 AWG 6-conductor wire
may be spliced to the supplied wire).
• After the concrete has cured, remove the plug and install the Slab Sensor
using the O-ring and screws provided.
WARNING
The Slab Sensor is located
outdoors and is likely to
become covered with dirt
that will adversely affect the
sensor's moisture detection
sensitivity. Therefore, it is
important to periodically clean
the sensor surface.
• Do not pull all the sensor cable from the Sensor Base. Leave an
additional 6-12" of sensor cable in the socket Base to ease servicing the
sensor.

SMC Installation and Operation Manual 11
HT# 059115-00 B
OUTDOOR SENSOR INSTALLATION
(Used Only when Sensor Type is set to Outdoor)
• The SMC does not come with the Outdoor Sensor (HT# 904220-
00). It must be ordered separately. See "Outdoor Sensor
Operation Overview" on page 6.
• Locate the sensor in the shade on the north side of the building.
• The sensor should never be in direct sunlight. Be sure the
location is away from any possible heat or cool sources.
• The sensor should be mounted approximately 10’ feet above
ground.
• Adhere the Outdoor Label provided to the back of the sensor
base.
• Use the Enclosure Base bottom knockout for the conduit. Use
the locknut to hold the conduit and enclosure base together.
• The sensor wires can be extended up to 500’ using 18 AWG
2-conductor shielded cable (HT# 703001-01).
• Do not connect the shield at the sensor end. However, connect
the shield at the control using terminal 17.
Outdoor Sensor
snap-in location
Shield
not connected
Conduit
Outdoor Label
on back of Sensor
Mounting
screws
location
Seal around
sensor and wall
Outdoor
drip-hole
Conduit
Well
Sensor
in well
Shield
Connect
To control
Immersion Well
3/8" ID 1/2" NPT
Immersion Temperature Sensor
Common
Supply
Pipe
Sensor
Enclosure
Sensor
Probe
WATER TEMPERATURE SENSOR INSTALLATION
Slab Supply and Return Sensors
• The provided Slab Supply and Return sensors (HT# 904250)
must be inserted in the provided wells (1/2"NPT, 3/8" I.D)
(HT# 904011-00). The wells must be inserted in the pipe where it
will be in uid ow .
• Make sure the supply sensor is installed approximately ten feet
of pipe downstream from the heat source to avoid temperature
uctuations.
• The slab return sensor can be installed in any convenient location
where the anti-freeze solution has returned from all the slab
branches.
• The sensor wires can be extended up to 500’ using 18 AWG
2-conductor shielded cable (HT# 703001-01).
• Do not connect the shields at the sensors' ends. However,
connect them to SMC terminals 27 and 29.
Boiler Return Sensor
• To help prevent thermal shock stress to the boiler, use the Boiler
Return Sensor. The SMC can function without this sensor.
However, when used in a Motorized Valve application, it prevents
the boiler return from dropping below the Minimum Boiler Return
setting. It does this by modulating the valve partially closed. See
"Minimum Boiler Return" on page 29.

12 SMC Installation and Operation Manual
HT# 059115-00 B
• This sensor should be an immersion type sensor (HT# 904250-00
or #904220-00). It must be inserted in a well (1/2"NPT, 3/8" I.D.)
(HT# 904011-00). Both the sensor and the well must be ordered
separately.
• The Boiler Return Sensor should be located after all the returns to
the boiler merge.
• The sensor wires can be extended up to 500’ using 18 AWG
2-conductor shielded cable (HT# 703001-01).
• Do not connect the shield at the sensor. However, connect it to
SMC terminal 31.
WARNING
Class 1 voltage wires (low
voltage) must use a different
knockout, conduit, and path
from any Class 2 voltage
wires (high voltage).
WIRING THE POWER
Terminals (1) through (3)
• If possible, provide a dedicated circuit breaker for the SMC. Make sure
not to connect the SMC to a circuit breaker shared with high inductance
devices such as relays, pumps, fans, or motors.
• Bring the 120 VAC 60 Hz power wires through the enclosure left bottom
knockout.
• Connect the hot line to terminal 1 (L).
• Connect the neutral line to the terminal 2 (N).
• Connect the ground to Earth ground terminal 3 (G). Do not use the
neutral line as a ground.
• Heat-Timer recommends the installation of a Surge Suppressor and a
Power Switch before the Power Line connection for safety and ease of
service.
PWR
4
123
L N G
120VAC L
N
Earth
Ground
OUTPUT WIRING
• The SMC outputs do not source any power. If power is needed to a specic
output, a separate power source must be wired in series with the output.
• Each of the output relays can switch a 6A resistive load at 120 VAC or a 1A
inductive load at 120 VAC.
• Each of the output relays has a LED to represent its status.
WARNING
Each of the pump relays can
operate a maximum of ¼ HP
pump. If a larger HP pump
is used, use a pump starter.
ALERT
Output relays do not source
any power.. A separate
power source must be used
when needed.
WIRING SYSTEM PUMP AND SLAB PUMP
• The Slab Pump is designed to circulate the water/antifreeze solution
through the slab radiant tubing.
• The System Pump circulates the boiler water through the boiler loop.
• A separate power source must be used to power each of the pumps. Use
the relay to make or break the power to the HOT (Line) connection to the
pump.
• The Slab Pump output has a Normally Open relay output.
• The System Pump output has a Normally Open (N.O.) and a Normally
Close (N.C.) outputs. Use the (N.O.) relay output to operate the pump.
PWR SYSTEM
PUMP
OR VALVE
BURNER
4 5 6
7
123
L N G
System
Pump
120VAC

SMC Installation and Operation Manual 13
HT# 059115-00 B
System Output Operation
System Pump Terminals (4) and (5)
• Whenever the SMC operates the boiler or the motorized valve, it activates
the System output. See "Slab Sensor Operation Overview" on page 4 and
"Outdoor Sensor Operation Overview" on page 6.
• After the SMC turns the boiler off or fully closes the motorized valve, it
keeps the System Pump energized for the Run-On period. The Run-On
period helps protect the boiler from reaching its limits by transferring its
energy into the system.
Slab Output Operation without Precipitation
Slab Pump Terminals (9) and (10)
• In Idle Mode, the SMC shall intermittently energize the Slab Pump relay. It
does this by energizing the pump for 15 seconds for every Antifreeze time
setting. See "Antifreeze" on page 30.
• Whenever the slab temperature drops to or below the ISP, the SMC shall
energize the Slab Pump relay to maintain the ISP.
• Whenever the slab temperature drops to or below the CWC setting,
the SMC shall energize the Slab Pump relay for 15 seconds for every
Antifreeze period setting. This reduces the possibility of freezing.
PWR SYSTEM
PUMP
OR VALVE
BURNER
SLAB
PUMP
ALARM
4 5 6 7 8 9 10 11
12
123
L N G
120VAC
Slab
Pump
Slab Output Operation with Precipitation
• Whenever the slab temperature drops to or below the WWC setting, the
SMC shall energize the Slab Pump relay to maintain the WWC during the
melting period.
WIRING TO A FLOATING MOTORIZED VALVE
(Requires System Startup Control Mode to be set to Motorized Valve)
Terminals (13) through (15)
• The SMC is capable of modulating a oating motorized valve.
• In this case use the SMC output terminal 14 as the Common. Wire it to the
24 VAC power source (transformer).
• Connect the transformer's other wire to the actuator Common terminal.
• Wire output terminal 13 on the SMC to the actuator Close terminal.
• Wire output terminal 15 on the SMC to the actuator Open terminal.
• The transformer is the motorized valve power source.
PUMP ALARM
SLAB
VALVE
CLOSE OPEN
SLAB TEMP/OUT
(BROWN)
SENSOR COM
(BLUE)
HEATER TEMP
(WHITE)
WATER DETECT
(GREEN)
HEATER PWR
(RED)
HEATER COM
(BLACK)
16 17 18 19 20 21
10 11
12 13 14 15
Black
Red
White
Floating
Motorized
Valve
Transformer
120
VAC
Com Open Close
WIRING TO A MODULATING MOTORIZED VALVE
(Requires System Startup Control Mode to be set to Motorized Valve)
• The SMC is capable of operating a current or voltage modulating motorized
valve.
• When operating a 0-10V modulating motorized valve use the SMC 0-10V
Output terminals 22 and 23. See "0-10V Modulating Boiler or Valve Wiring"
on page 14.
• When operating a 4-20mA modulating motorized valve use the SMC
4-20mA Output terminals 24 and 25. See "4-20mA Modulating Boiler or
Valve Wiring" on page 14.

14 SMC Installation and Operation Manual
HT# 059115-00 B
WIRING TO AN ON/OFF BOILER
Burner Terminals (7) and (8)
• When in Motorized Valve Control Mode, the SMC is designed to activate
a boiler. The boiler can be either an On/Off or a modulating.
• In On/Off Boiler mode, the boiler will operate based on its own internal
limits. Wire the burner limit in series with the SMC terminals 7 and 8.
• Some modulating boilers (Control Mode set to Boiler) require the use of
terminals 7 and 8 as an activation. In this case, wire them in series with
the boiler limit.
PWR SYSTEM
PUMP
OR VALVE
BURNER
SLAB
PUMP
ALARM
4 5 6 7 8 9 10
11
123
L N G
Boiler
Limit Circuit
WIRING TO A MODULATING BOILER
(Requires System Startup Control Mode to be set to Boiler)
• One of the SMC Control Modes is designed to modulate a single boiler.
In this option it can modulate either a 0-10V boiler or 4-20mA boiler.
• Some modulating boilers may require an activation signal in addition
to the modulating output. In this case, wire the SMC Burner output
terminals to the boiler activation.
WARNING
To avoid control or equipment
damage, make sure to
match the boiler modulating
input signal to the control's
modulating output signal.
0-10V Modulating Boiler or Valve Wiring
Terminals (22) and (23)
• Wire the boiler or valve (V or +) terminal to the SMC terminal 22 (V+).
• Wire the boiler or valve (-) terminal to the SMC terminal 23 (-).
4-20mA Modulating Boiler or Valve Wiring
Terminals (24) and (25)
• Wire the boiler or valve (+) terminal to the SMC terminal 24 (mA).
• Wire the boiler or valve (-) terminal to the SMC terminal 25 (-).
0-10V
OUTPUT
4-20mA
OUTPUT
HEATER COM
(BLACK)
20
21 22 23 24 25
V+ - mA -
V+ -
Burner/ Valve 0-10V Modulation
0-10V
OUTPUT
4-20mA
OUTPUT
HEATER COM
(BLACK)
20 21
22 23 24 25
V+ - mA -
mA
-
Burner / Vallve 4-20mA Modulation
WIRING ALARM OUTPUT TO VISUAL/AUDIO ALARM
Terminals (11) and (12)
• The SMC is designed to enable the Alarm output whenever any of the
sensors fail or the heating system fails. See "Alarm List" on page 36.
• The Alarm output terminals do not source any power. A separate power
source must be supplied.
• Connect the Alarm relay output to any type of alarm. An optional Heat-
Timer Vis-U-Larm (visual audio alarm (HT #925011-00)) can be used. It
has both a Red Alarm light and a sound alarm.
• The SMC's alarm output is capable of switching 1A Inductive, 6A
Resistive at 120VAC.
SYSTEM
PUMP
OR VALVE
BURNER
SLAB
PUMP ALARM
SLAB
VALVE
CLOSE OPEN
4 5 6 7 8 9 10 11 12 13 14 15
3
G
120VAC
Alarm

SMC Installation and Operation Manual 15
HT# 059115-00 B
WIRING ALARM OUTPUT TO BMS
Terminals (11) and (12)
• The SMC is designed to enable the Alarm output whenever any of the
sensors fail or the heating system fails. This output can be connected
to a Building management System (BMS) to enable remote alarming
and reporting.
• The Alarm output terminals do not source any power.
• Connect the SMC Alarm output to a dry-contact BMS alarm input.
WIRING TO 4-20MA REMOTE SET POINT
(Requires System Startup Control Mode to be set to Ext. Interface)
Terminals (24) and (25)
• One of the SMC Control Modes is designed to provide a 4-20mA
remote temperature set point. This set point can be used by a multi-
boiler control (Mini-MOD, SQ-Elite, Multi-MOD Platinum, HWRQ
Platinum) to operate multiple modulating or staging boilers.
• Wire the SMC terminal 24 (mA) to the multi-boiler control's (+) terminal.
• Wire the SMC terminal 25 (-) to the multi-boiler control's (-) terminal.
0-10V
OUTPUT
4-20mA
OUTPUT
SLAB
SUPPL
TEMP
21
22 23 24 25
26
V+ - mA -
mA
-
4-20mA Set Point
INPUT WIRING
• All of the SMC's inputs are either sensors or dry-contact. Do not
connect any power to the input terminals as it may damage the input.
WARNING
Class 1 voltages wires (low
voltage) must use a different
knockout, conduit, and path
from any Class 2 voltage
wires (high voltage).
CLOSE OPEN
SLAB TEMP/OUT
(BROWN)
SENSOR COM
(BLUE)
HEATER TEMP
(WHITE)
WATER DETECT
(GREEN)
HEATER PWR
(RED)
HEATER COM
(BLACK)
16 17 18 19 20 21
15 22
Snow Melt
Sensor
Brown
Blue
White
Green
Red
Black
WIRING THE SLAB SENSOR
(Used when System Startup Sensor Type is set to Slab)
Terminals (16) through (21)
• The Slab Sensor is designed to measure the slab temperature and
detect precipitation. See "Slab Sensor Installation" on page 10.
• The sensor wires can be extended with an additional 400' of
6-conductor cable.
• The Brown sensor wire connects to terminal 16 and Blue sensor wire
connects to terminal 17. Both wires read the slab temperature.
• The White sensor wire connects to terminal 18 and Blue sensor wire
connects to terminal 17. Both wires read the temperature of the slab
heater. Its Ohm reading should be close to the temperature read on
the Slab Temp display when control is in Melting or Idling stages.
• The Green sensor wire connects to terminal 19 and Blue sensor wire
connects to terminal 17. Both wires detect precipitation.
• The Red sensor wire connects to terminal 20 and Black sensor wire
connects to terminal 21. Both wires are the sensor heater power.
This heater protect the sensor from freezing.
ALERT
Make sure that the sensor surface is clean to provide accurate precipitation
readings and control operation. Periodic inspection and cleaning is recommended.

16 SMC Installation and Operation Manual
HT# 059115-00 B
WIRING THE OUTDOOR SENSOR
(Used when System Startup Sensor Type is set to Outdoor)
Terminals (16) and (17)
• The Outdoor Sensor is used only when it is difcult to use a Slab
Sensor. See "Outdoor Sensor Installation" on page 11.
• You can extend the sensor wires up to 500’ by splicing it with
2-conductor 18AWG shielded cable (Belden #8760 or equivalent).
• Temperature sensor wires have no polarity. Connect the sensor wires
to the SMC's terminal 16 (Slab Temp/Out/Brown) and terminal 17
(Sensor Com/ Blue).
• Connect the shield to terminal 17 with one of the sensor wires. Do
not connect the shield at the sensor.
SLAB TEMP/OUT
(BROWN)
SENSOR COM
(BLUE)
HEATER TEMP
(WHITE)
WATER DETECT
(GREEN)
HEATER PWR
(RED)
HEATER COM
(BLACK)
16 17 18 19 20 21
Shield
Outdoor Sensor
WIRING THE BOILER RETURN SENSOR
(Available in Motorized Valve Control Mode Only)
Terminals (30) and (31)
• The use of the Boiler Return to help protect the boiler from
condensation and thermal shock is optional. A Heat-Timer
temperature sensor (HT #904250-00 or HT# 904220-00) immersed in
a 3/8 ID well (HT# 904011-00) is required. Both the sensor and well
must be purchased separately. See "Boiler Return Sensor" on page 11.
• If the Boiler Return Sensor is connected, the SMC will display its
temperature during melting and below the ISP temperature.
• If the Boiler Return Sensor value was below the Minimum Return,
the SMC will modulate the motorized valve to increase the return
temperature.
• The sensor wires can be extended up to 500’ using 2-conductor
18AWG shielded cable (Belden #8760 or equivalent ).
• Temperature sensors have no polarity. Connect the sensor wires to
the SMC's terminals 30 and 31.
• Connect the shield to the circled terminal 31 with one of the sensor
wires. Do not connect the shield at the sensor.
SLAB
SUPPLY
TEMP
SLAB
RETURN
TEMP
BOILER
RETURN
TEMP
SHUTDOWN
/ENABLE
PROVE
25
26 27 28 29 30 31 32 33 34 35
Shield
Boiler Return Sensor in Well
WIRING THE SLAB SUPPLY AND RETURN SENSORS
Slab Supply Terminals (26 )and (27)
Slab Return Terminals (28) and (29)
• The SMC is designed to use the Slab Supply and Slab Return
Temperature Sensors to calculate the energy put into the slab.
• Each sensor must be immersed in a 3/8 ID well (HT #904011-00).
Both Sensors and their wells are supplied with the SMC.
• You can extend the sensor wires up to 500’ by splicing it with
2-conductor 18AWG shielded cable (Belden #8760 or equivalent).
• Connect the Slab Supply sensor wires to the SMC 26 and 27
terminals.
• Connect the shield to the circled terminal 27 with one of the sensor
wires. Do not connect it to the sensor.

SMC Installation and Operation Manual 17
HT# 059115-00 B
• Connect the Slab Return sensor wires to the SMC 28 and 29
terminals.
• Connect the shield to the circled terminal 29 with one of the sensor
wires. Do not connect it at the sensor.
SLAB
SUPPLY
TEMP
SLAB
RETURN
TEMP
BOILER
RETURN
TEMP
SHUTDOWN
/ENABLE
PROVE
25
26 27 28 29 30 31 32 33 34 35
Shield
Slab Supply Sensor in Well
Shield
Slab Return Sensor in Well
SLAB
SUPPLY
TEMP
SLAB
RETURN
TEMP
BOILER
RETURN
TEMP
SHUTDOWN
/ENABLE
PROVE
RS485
25
26 27 28 29 30 31 32 33 34 35
Shutdown
/ Enable
SLAB
RETURN
TEMP
BOILER
RETURN
TEMP
SHUTDOWN
/ENABLE
PROVE
RS485
28 29
30 31 32 33 34 35
Prove
WIRING THE SHUTDOWN / ENABLE
Terminals (32) and (33)
• These input terminals are used as a Shutdown or an Enable signal
inputs. Their function varies depending on the Startup Menu External
Input option selected. See "External Input" on page 22.
• The signal provided must be a dry contact input. No voltage can be
placed across these terminals.
• The Shutdown feature can be used whenever it is desirable to turn off
the SMC from a remote location or another controller by shorting the
terminals.
• The Enable feature can be used whenever it is desirable to turn on
the SMC from a remote location or another controller by shorting the
terminals.
• The SMC shall close the motorized valve and de-energize the boiler
output when the Shutdown is activated or the Enable is de-activated.
The System Pump and slab pump relays will remain energized for the
Run-On delay period and then turn off.
• Bring the two dry contact wires to the SMC 32 and 33 terminals.
WIRING THE PROVE
Terminals (34) and (35)
• The Prove feature is provided to check system component operation.
It can be used to check on the combustion air damper or the system
pump ow before energizing the boiler or opening the valve.
• If the Prove input is open, the SMC will enable only the System
Output. The Burner output will be off and the motorized valve will be
closed.
• A factory-installed jumper acts as the system prove signal. Do not
remove the jumper unless it is replaced by a System Prove signal.
• Bring the two wires from the dry contact to the Prove 34 and 35
terminals. No voltage can be placed across the Prove terminals.

18 SMC Installation and Operation Manual
HT# 059115-00 B
WIRING TO BACNET MSTP
• For the SMC to communicate over the BACnet MSTP network, the use of the BACnet Interface Module
is required. The BACnet Interface Module must be ordered separately (HT# 926781-00).
• Connect the provided CAT-5 cable to both the BACnet Interface Module (Product Comm Ethernet
port) and the SMC's (RS485 port). The BACnet Interface Module is powered through the control. See
BACnet Interface Module Manual for BACnet setup.
PWR SYSTEM
PUMP
OR VALVE
BURNER
SLAB
PUMP ALARM
SLAB
VALVE
CLOSE OPEN
0-10V
OUTPUT
4-20mA
OUTPUT
SLAB
SUPPLY
TEMP
SLAB
RETURN
TEMP
BOILER
RETURN
TEMP
SHUTDOWN
/ENABLE
PROVE
RS485
SLAB TEMP/OUT
(BROWN)
SENSOR COM
(BLUE)
HEATER TEMP
(WHITE)
WATER DETECT
(GREEN)
HEATER PWR
(RED)
HEATER COM
(BLACK)
16 17 18 19 20 214 5 6 7 8 9 10 11 12 13 14 151 2 3 22 23 24 25 26 27 28 29 30 31 32 33 34 35
PROGRAM RUN
DO NOT APPLY ANY VOLTAGE
TO INPUT TERMINALS
L N G
ACTIVE OUTPUTS
SYSTEM
BURNER
SLAB PUMP
ALARM
VALVE CLOSE
VALVE OPEN
POWER
SMC
SNOW MELT CONROL
OUTPUT RATINGS: 6A RESISTIVE, 120VAC
MAXIMUM 15A TOTAL FOR ALL CIRCUITS
INPUT RATINGS: 120 VAC 60 Hz, 48VA MAX.
CAUTION: Risk of Electric Shock.
Use Copper Conductors Only.
V+ - mA -
ENCLOSED
ENERGY
MANAGEMENT
EQUIPMENT
99RA
ALARM MENU
SLAB SUP 120o
rtn 102o
38oF
__________________________
Melting in Progress
Boiler Return = 142
o
F
BACnet Interface Module
MSTP
1 2 3
A GND B PRODUCT
COMM RS485
Ethernet Cable
(Supplied)
BACnet MSTP wiring
to BACnet network
A (+)
Ground (GND)
B (-)
ACTIVATE THE BATTERY
• The coin Lithium battery (CR2032) (HT# 020002-00) is on the back on
the display module. It enables the control to maintain the clock time for
up to 100 days of power outage. The clock is used in many aspects of
the control operation including maintaining a 24-hour history of every
sensor.
• To activate the battery, rst disconnect the control power.
• Unscrew and remove the Enclosure Display Module to reveal the back
of the control CPU Board.
• Remove the plastic tab that covers the battery to allow the battery
holder contacts to touch the battery.
ALERT
Do not activate the battery unless you plan to keep the control continuously
powered. If the control has no power, the battery will lose its charge in 100 days.
Battery

SMC Installation and Operation Manual 19
HT# 059115-00 B
DISPLAY AND BUTTONS
Display
The SMC display layout provides information that gives an immediate picture of the operation status. All
the information is brightly displayed. It can be viewed in virtually any light.
• Each of the button functions is presented on the bottom of the display.
• The area above the button function displays messages about the control operation. In normal operation
it displays the current operating mode, sensor failures, and boiler return or boiler modulation percent.
• The display top area shows the critical sensor temperatures.
Buttons
Each of the button functions vary based on the current screen. See the Button Function Table below.
BUTTON Left ◄ or ▲ ▼ or ► Right
Default
ALARM
Blinks when an Alarm is
active. Otherwise, does not
function
Has no function MENU
Enters the menu
Menu BACK
Goes back one menu step
▲ ▼ Scrolls up or down
the menu
SELECT
Selects the current menu
item
Setting BACK
Goes back one menu step
▲ ▼ Increases or
decreases the current
setting value.
SAVE
Saves the current setting
Alarm Menu BACK
Goes back to default screen ▲ACKNOWLEDGE▲OK
Goes back to default screen
History
BACK
Goes back to one menu
step
◄ ► Scrolls to a specic
point in time
NEXT
Goes to the next sensor
history
SLAB SUP 120o
38oF rtn 102o
--------------------------------
Melting at 38oF
Boiler Return 142oF
ALARM MENU
Slab Temp. Supply and
Return Temp.
Messages
Buttons
Button Function
SETTING THE CONTROL TO FACTORY DEFAULTS
To Reset the SMC control to its original factory defaults, power down the
control. Hold down the two right most buttons while powering the control
back up until the TOTAL CLEAR STARTED screen appears. The
Display will direct you to the Startup menu to program the control to select
the operating modes.
TOTAL CLEAR STARTED
Release buttons
and
Please wait

20 SMC Installation and Operation Manual
HT# 059115-00 B
DISPLAY MESSAGES
• Cold-Weather Cutoff The slab temperature is at or below the CWC setting. "Cold Weather Cutoff
(CWC)" on page 28.
• Heating Disable The External Input option is set to Enable and terminals 32 and 33 are open.
"External Input" on page 22.
• Hold Boil.Rtn. 140°F The Boiler Return Sensor reading dropped below the Minimum Boiler Return.
The SMC closes the valve to increase the boiler return temperature. "Minimum
Boiler Return" on page 29.
• Hold Idle at 34°F The slab temperature is below the ISP. The SMC modulates the outputs to
maintain the slab at 34°F. "Idle Set Point (ISP)" on page 26.
• Idle State The slab temperature is between the WWC and the ISP with no precipitation or
moisture detected. "Slab Sensor Operation Overview" on page 4.
• Interface Module Err The BACnet Interface Module is not communicating to the BAcnet network.
• Melting at 38°F Moisture has been detected. The control is increasing the Slab temperature to
38°F. "Slab Sensor Operation Overview" on page 4.
• Outdoor Snr.Failure In Outdoor Sensor Mode, the Outdoor Sensor is reading Open or Short (---).
• Shutdown Active The External Input option is set to Shutdown and terminals 32 and 33 are
Shorted. See "External Input" on page 22.
• Slab Heater Failure The Slab Sensor wiring is not correct or the sensor is damaged.
• Slab Rtn.Target=120°F In Outdoor Sensor Mode, the Slab Return Temperature is below the Return
Target during the melting period.
• Slab Snr.Failure In Slab Sensor Mode, the Slab Sensor temperature is reading Open or Short
(---).
• Summer The Season is set to Summer. No output is activate. See "Season" on page 26.
• SYS Prove.Failure The Prove input was not shorted (terminals 34 and 35). "Wiring the Prove" on
page 17.
• Waiting for SYS Prove The Prove input was shorted and then opened during boiler call (terminals 34
and 35). "Wiring the Prove" on page 17.
• Warm Weather Cutoff The slab temperature is above the WWC setting. No output is activate. "Slab
Sensor Operation Overview" on page 4