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The control has a built-in time clock that can be set manually
or automatically by the Internet. A battery-less backup allows
the control to keep time for up to 4 hours without power. The
time clock supports automatic adjustment for Daylight Saving
Time (DST) once the day, month and year are entered. Use
the Time menu to set the correct time, day, month and year. If
the time and date is set incorrectly, the control may be unable
to communicate to the mobile app.
Time Clock
Away Operation
tekmarNet Scene Operation
While on vacation and away from a building, it may not be
necessary to operate the snow melting system. The away
feature allows the user to shut off the snow melting system to
maximize energy savings. The Away feature can be activated
through the:
• Away menu
• tekmar Connect mobile app
• tekmarNet User Switch 480 or 481
• tekmarNet Gateway 482 or 485
The tekmarNet system supports up to 8 scenes.
The 670 supports tekmarNet scenes 1 (normal operation)
and 2 (away).
During tekmarNet scenes 3 through 8, the 670 remains in
scene 1 (normal operation).
Warm Weather Shut Down
Cold Weather Cut Off
During warm weather, the slab is warm enough to naturally
melt snow or ice. The control has a Warm Weather Shut Down
(WWSD) setting in the Temperatures menu that prevents the
control from entering Melt, Idle or Storm operation in order to
conserve energy. The control shows, "System is Off – Warm
Weather Shut Down" on the display when WWSD is in effect.
Automatic (Auto)
The control enters WWSD when both the slab temperature
and the outdoor temperature exceed the Melting Setpoint
temperature setting by more than 2°F (1°C).
Manual WWSD
The control enters WWSD when the outdoor air temperature
exceeds the WWSD setting by 1°F (0.5°C) and when the
slab temperature exceeds 34°F (1°C). The control exits
WWSD when the outdoor air temperature falls 1°F (0.5°C)
below the WWSD setting or if the slab temperature falls
below 34°F (1°C). This allows the Melting Setpoint setting
to be set higher than the WWSD. This is useful when high
slab temperatures are required to melt the snow or ice. An
example of this are installations using paving bricks on top
of sand and concrete layers.
Maintaining the melting or idling setpoint temperature during
extremely cold temperatures is not only expensive but may
be impossible if the heat loss of the slab exceeds the input
capacity of the heating plant or electric cable. When the
outdoor air temperature drops below the Cold Weather Cut
Out (CWCO) temperature
and
the slab is below freezing,
the control does not operate the boiler but the system pump
continues to run. This is a safety and energy saving measure.
The control shows, "System is Off – Cold Weather Cut Off"
on the display when CWCO is in effect. If the snow melting
system is operating, and the outdoor air temperature falls
below the CWCO setting
and
the slab is above freezing, then
it continues melting and stops once the slab is dry. When the
temperature reaches the CWCO setting in an actively melting
system with an 090 or 094, melting is suspended until the
outdoor temperature rises above the CWCO setting at which
time melting is resumed. If an 090 or 094 is not installed,
melting is permanently stopped when CWCO is in effect and
melting does not resume when the temperature rises above
the CWCO setting.
