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Sequence of Operation
Snow Melting Overview
A snow melting system can offer a safe, convenient, and cost
effective way of removing snow and ice from the snow melting
slab and similar surfaces. Safety is increased by activating
the snow melting system as soon as the snow falls rather
than waiting for mechanical snow removal after snow has
accumulated. This eliminates slip hazards and reduces the
risk of injury by mechanized snow melting equipment, thereby
reducing potential liability costs. The elimination of snow plow
equipment and corrosive salts also reduces damage to the
slab surface and to the environment. When controlled correctly,
snow melting systems can be cost competitive compared to
mechanical snow removal.
The snow melting control can operate in one of four
different ways:
Melt
Heats the slab to melt snow or ice. Default is 36°F (2°C)
Idle
Preheats the slab just below freezing to shorten the
time required to melt snow. Default is off.
Melt
–
Automatic Start and Stop
Automatic start and stop operation requires the installation
of a Snow/Ice Sensor 090 (65' or 20 m cable) or 094 (208'
or 63 m cable). The sensor is installed in-slab level with the
melting surface. The control continually monitors the sensor
for the presence of moisture and slab temperature conditions
in which snow or ice may be present. When moisture is
detected, the control shows “Sensor Water Status – Wet”
in the Slab Status menu. When the sensor is dry the control
shows “Sensor Water Status – Dry”. The control includes a
Sensitivity setting in the Temperatures menu that allows the
installer to adjust the amount of moisture required to start and
stop the melting operation. In areas with low amounts of dust
and/or air pollution, the sensitivity may need to be increased.
The default sensitivity setting is Auto. This setting allows the
control to automatically determine the best suitable sensitivity
Push STOP Button
090 or 094 and Slab Dry and
Add Melt Time Elapses
or
Idle
Off
WWSD
Mobile App Stop Button
Gateway 482 or 485 Stop Message
090 or 094 Detects Water
Exits
CWCO
Melt
Suspended
Enters
CWCO
Melting
Auto
Start/
Auto
Stop
setting for the installation.
When moisture is detected and the slab and outdoor tempera-
tures are at or below freezing, the control will automatically
start the snow melting system. As the snow or ice melts and
the slab dries off, the sensor also dries off at the same time.
When the sensor is dry, the snow melt system automatically
shuts off. If there are low spots on the slab surface that dry
off slower than the sensor, additional melting run time can be
included by adjusting the Additional Melt Time setting in the
Temperatures menu.
If the snow melting system is manually stopped, the snow/
ice sensor must fully dry before it is able to detect a new
snow fall and automatically start the snow melting system.
Snow/Ice Sensor
090 or 094
The slab temperature must reach the slab target in order for the
system to shut off automatically. The capacity of the heat source
must be sized to ensure melting as low as the cold weather cut
off. In addition, the heat source maximum temperature setting
must be set to provide the full capacity of the heating appliance.
For example, boiler aquastats should be set to 180°F (82°C).
Failure to meet these requirements may result in the snow melting
system not automatically shutting off when the slab is dry.
Outdoor
Temperature
Slab
Temperature
MELT
IDLE or STORM
WWSD
CWCO
Control enters
Idle and waits
for Melt Enable
Storm
Temporarily preheats the slab just below freezing to
shorten the time required to melt snow. Default is off.
Off
Snow melting system is off
The display shows the control operation in the home screen.
