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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 8 of 15
May 2008
ZONE ASSIGNMENT
The SMMC-3 uses the concept of a zone system to most
efficiently control snow/ice melting equipment. The term
“zone” means an area (either surface area or roof/gutter
area, or some combination of both) heated by a specific
set of snow/ice melting equipment that is controlled in a
common manner. The SMMC-3 allows for up to three
zones, and each zone can have multiple moisture sensors
for, say, roof/gutter, aerial and/or surface snow/ice
detection. If any one of the sensors detects moisture, the
heating equipment may be energized. The moisture
sensor in the zone should be generally, surrounded by the
heating equipment to ensure that the heating equipment is
only energized when there is snow/ice present in the zone.
Zones can be used to represent different areas; for
example a parking ramp area could be one zone while
roof/gutter de-icing on the same building could be another
zone. Similarly, two sidewalks on different sides of the
same building (possibly one on the north side and one on
the south side) could represent two separate zones. The
perimeter of a football stadium could be split into three
separate zones to reflect different weather conditions on
different sides of the building.
MANUAL OPERATION
The power to any one of the snow-melting zones may be
activated manually by pressing and holding the ZONE X
button until the information below appears on the LCD
screen. Manual activation will only work a long as the
ambient temperature is below the SMMC-3 shut-off
temperature. The duration of the time the zone will remain
energized (Time Delay) is pre-set to 2.0 hours; this can be
adjusted by following the programming instructions below.
The minimum and maximum settings possible are noted on
the LCD, adjustable in 0.5 hour increments.
Pressing UP increases the delay time.
Pressing DOWN decreases the delay time.
Press the SET button to accept the chosen delay time.
Once the delay time is set, the SMMC-3 returns to normal
control function, and energizes the heating equipment for
the selected zone.
To de-energize the manually activated heating
equipment, use the toggle switch on the front panel.
When operating in Mode 2 – Priority, the manual
override works as described if no snow melting zones
are energized. If any snow-melting zone is energized
the manual override only works to energize the higher
priority zone, thereby de-energizing the lower priority
zone.
It is important to note that manual operation is not
possible if the SMMC-3 has already energized the zone,
and that manual control will be overridden if the zone
moisture sensor detects precipitation.
M. Time Delay Zone 1
min.0 <2.0H> Max.10
Temperature
at SMTS-1 location
Temperature
Value & Units
°C or °F
(only sensors activated will show)
A1=SMAS-1 or SMGS-1 ZONE 1
A2=SMAS-1 or SMGS-1 ZONE 2
A3=SMAS-1 or SMGS-1 ZONE 3
(only sensors activated will show)
P1=SMPS-1 ZONE 1
P2=SMPS-1 ZONE 2
P3=SMPS-1 ZONE 3
M1= Mode 1 Independent
M2= Mode 2 Priority
LCD Explanation
Outside T=-3°C
A1-A2-A3-P1-P2-P3-M1