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PO. Box 726 n TULSA, OK 74101 n TEL 918-627-5530 n FAX 918-641-7336 n www.nelsonheaters.com
GA-2318, R1
Sheet 5 of 15
May 2008
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.