Emerson SMMC-3 User Manual

S M M C - 3 M A N U A L

TABLE OF CONTENTS

GENERAL INFORMATION...........................................................................................................3

Pre-Programmed Configuration ............................................................................................................................ 3

WARNINGS....................................................................................................................................4

INSTALLATION..............................................................................................................................4

Pre-Programmed Connections.............................................................................................................................. 5

SYSTEM CHECK...........................................................................................................................6

OPERATION...................................................................................................................................7

Mode 1 – Independent ........................................................................................................................................... 7

Mode 2 – Priority .................................................................................................................................................... 7

Zone Assignment ................................................................................................................................................... 8

Manual Operation................................................................................................................................................... 8

Programming Instructions...................................................................................................................................... 9

TROUBLESHOOTING GUIDE ...................................................................................................12

SMMC-3 Control panel (access cover removed) ............................................................................................... 13

SPECIFICATIONS .......................................................................................................................14

Sensor Extension Wire Specifications ................................................................................................................ 14

LIMITED WARRANTY AND LIABILITY.....................................................................................15

GE NER AL INFOR M ATION

Manual Override

The SMMC-3 Control Panel manages snow and ice melting equipment for sidewalks, driveways, gutters, downspouts,
etc. Suitable for controlling all types of heating cable systems, the SMMC-3 can monitor snow and ice accumulation in
three separate zones. The SMMC-3 programming allows each zone to be controlled independently or on a priority mode
basis. In the priority mode, one zone can be given priority and the other zones cannot be energized until the melting/de­icing in that zone is complete. This can reduce the loading on the system by ensuring that multiple zones are not
energized simultaneously. The SMMC-3’s program allows customization of the key elements necessary for intelligent
and efficient snow melting control.

The SMMC-3 can access information from three different types of moisture sensors – surface (SMPS-1), aerial (SMAS-

1) and gutter (SMGS-1) and one temperature sensor (SMTS-1). The surface, aerial and gutter sensors detect moisture
from snow, ice, sleet, etc. and send appropriate signals to the SMMC-3. Similarly, the temperature sensor sends
temperature data back to the SMMC-3. Independent temperature and moisture information is processed by the SMMC-3
to ensure that heating equipment will only be energized when precipitation occurs during freezing conditions. For each of
the SMMC-3 control zones, up to two individual moisture sensors can be connected. However, for each zone only one of
these may be a surface sensor. Each SMMC-3 must have a temperature sensor, SMTS-1, in order to function. A SMTS­1 is included with each SMMC-3.

The SMMC-3 is housed in an enclosure suitable for commercial/industrial applications (NEMA 12) and features an LCD
display, programming and associated indicator lights for operation of each zone.

The SMMC-3 is powered by 120VAC; control relays provide a 120VAC output to operate external contactors.
See Fig. 1 & 2.

PRE-PROGRAMMED CONFIGURATION

The SMMC-3 Control Panel is delivered preprogrammed for a single zone system, for use with either an aerial (SMAS-1)
or gutter (SMGS-1) sensor. (Note that the SMMC-3 does not distinguish between the gutter and aerial sensors). The de­energize temperature (the SMMC-3 will not energize the heating equipment when the ambient temperature is warmer
than this) is pre-set to 37°F (3°C), and relay hold time (the length of time that the heating equipment will stay energized
after it no longer senses the presence of ice/snow in the zone) is 3.0 hours. If the snow/ice melting system has been
designed to operate in this manner, then no programming is required: simply wire as per the following instructions.

Output Relay

Status Lights

(on when ZONE

heating is energized)

Fig.1

Control PanelSMMC-3

Buttons

SMMC-3

LCD

Programming

Buttons

Sensor Status

Lights

(on when ZONE

sensor is energized)

PO. Box 726 n TULSA, OK 74101 n TEL [phone] n FAX [phone] n www.nelsonheaters.com

ON/OFF

Access Cover

Switch

GA-2318, R1

Sheet 3 of 15

May 2008

Installation & Operat ing Instructions

120 VAC, to contactor coils

power contactors(s)

C

-3

Fig.3

Mou n ting: m ou nts to wall via thr ee #10 screw s

mounting screw

Fi g.2

Sa mple Application Il lustrati on

snow/ice

sensor

options

maximum 2 sensors

per zone

WARN ING S

1. A qualified electrician must install the SMMC-3.

2. If after carefully reading these instructions you still
have questions regarding installation operation or
maintenance of this product, call the numbers listed
for assistance.

3. Prior to installation, check the SMMC-3 Control
Panel for possible shipping damage. Do not install a
damaged SMMC-3 Control Panel.

4. All heating equipment, controls & associated
systems must be installed in compliance with the
latest editions of all applicable electrical codes and
ordinances.

5. The SMMC-3 has been designed to accept only
Nelson moisture and temperature sensor inputs.
The risk of fire or electric shock exists if the SMMC­3 is connected to any device other than a Nelson
sensor.

INSTA LL ATION

1. Mount the SMMC-3 securely to the wall with three
#10 screws, mount in an upright position in an indoor
location, in an area that is dry and not subject to
temperature extremes. See Fig. 3 for mounting
details.

2. Four ½” connectors have been installed on the
SMMC-3 Control Panel box to facilitate connection of
electrical conduit for input power supply wiring, and
contactor output wiring.

3. Remove the lower front access cover to begin
connecting wiring. On the back of the access cover is
a wiring guide label.

4. Connection to the SMMC-3 is done through terminal
blocks. Fish the wire being connected through the
adjacent knock-out, and pull out approximately 12” of
wire. The top half of the terminal block is removable
for easy wiring; gently pull up on the top half to
remove. After connecting the wire to the top half
gently set it back into the base while carefully pulling
back excess wire through the knock-out.

PO. Box 726 n TULSA, OK 74101 n TEL [phone] n FAX [phone] n www.nelsonheaters.com

GA-2318, R1

Sheet 4 of 15
May 2008

*

*maximum 1 SMPS-1 sensor per zone

SMMC-3

power contactors(s)

power contactors(s)

120 VAC, 450 VA

6. Do not connect heating equipment directly to the
SMMC-3 Control Panel. The SMMC-3 control relays
provide an output to operate external contactors. Each
output provides a maximum current output of 1.25A.
The risk of fire or electric shock exists if the heating
equipment is directly connected to the SMMC-3 Control
Panel.

7. These instructions must be saved and made available
to owners or users of this product and/or transferred to
future owners.

8. Secure the SMMC-3 in an accessible location. The
SMMC-3 Control Panel is not suitable for installation
environments subject to condensing moisture or those
exposed to temperature extremes.

9. Avoid shock or vibration.

locations

5. The SMMC-3 terminal blocks serve 5 distinct connection sectors (see Fig 4), they are:

1. SMTS-1 – temperature sensor.

2. SMAS-1 aerial sensors / SMGS-1 gutter sensors (one each per zone).

3. SMPS-1 in-ground sensors (one each per zone).

4. Output to power contactors (one each per zone).

5. Control power input.

Connection to each sensor is described below:

6. The SMTS-1 is connected to the left-most terminal block, identified as TEMP. SENSOR. The SMMC-3 will not
function if the SMTS-1 wire color codes are not properly matched at the terminal block. See Fig. 4

7. The SMAS-1 or the SMGS-1 may be connected to any one of the 3 terminal blocks, identified as A/G. SENS. The
Zone number at the terminal block correlates to a snow-melting zone, ensure that the sensor is connected to the
proper zone terminal. The SMMC-3 will not function properly if the SMAS-1 / SMGS-1 wire color codes are not
properly matched at the terminal block. See Fig. 4

8. The SMPS-1 may be connected to any one of the 3 terminal blocks identified as PAV. SENS. The zone number at
the terminal block correlates to a snow-melting zone; ensure that the sensor is connected to the proper zone
terminal. The SMMC-3 will not function properly if the SMPS-1 wire color codes are not properly matched at the
terminal block. See Fig. 4

9. The outputs to the power contactors may be connected to any one of the 3 terminal blocks in the – OUTPUT TO
POWER CONTACTORS – segment, ZONE #1, 2 OR 3.
The Zone number at the terminal block correlates to a snow-melting zone; ensure that the output being connected
matches the sensor inputs connected. The output wire must be connected with the polarity as noted, ensure voltage
and amperages are suitable for the contactor being used. The SMMC-3 will not function properly if the output
connections are improperly made. See Fig. 4

10. The power supply is connected to the right-most terminal block, identified as POWER SUPPLY. The power supply
wires must be connected with the polarity as noted, ensure supply voltage is correct and noted ampacity is
available. The SMMC-3 will not function if the power supply connections are improperly made. See Fig. 4

11. At this point a quick check on the power supply wiring can be made. Energize the supply circuit for the SMMC-3
Control Panel, and turn on the SMMC-3 via the toggle switch, the LCD should illuminate at this point. Reattach the
front access cover; connection of the SMMC-3 is complete.

12. Each of the SMAS-1, SMGS-1 or SMPS-1 sensors connected to the SMMC-3 must be activated by programming
the SMMC-3; to do so, follow the steps in the programming section of this instruction.

PRE-PROGRAMMED CONNECTIONS

1. Remove lower access panel on the SMMC-3.

2. Connect the temperature sensor lead to the temperature sensor terminal block.

3. Connect the aerial or gutter sensor lead to the Zone 1 sensor terminal block.

4. Connect the control wire from the contactor coil to the Zone 1 output terminal block, 120VAC only. DO NOT

CONNECT OUTPUT DIRECTLY TO THE LOAD. THIS WILL DAMAGE THE SMMC-3 AND CAN RESULT IN
RISK OF INJURY OR FIRE.

5. Connect 120VAC to the power supply terminal block, verify polarity.

6. Turn on the power to the SMMC-3 using the toggle switch on the front panel.

7. System is now operational.

PO. Box 726 n TULSA, OK 74101 n TEL [phone] n FAX [phone] n www.nelsonheaters.com

GA-2318, R1

Sheet 5 of 15

May 2008