Install Instructions

© 2019 tekmar 671
_
D - 08/19 31 of 36
The control has a built-in time clock that can be set manually.
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.
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
• tekmarNet User Switch 480 or 481
• tekmarNet Gateway 482 or 486
The tekmarNet system supports up to 8 scenes.
The 671 supports tekmarNet scenes 1 (normal operation)
and 2 (away).
During tekmarNet scenes 3 through 8, the 671 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. The control turns
the snow melting system off when the outdoor air temperature
drops below the Cold Weather Cut Off (CWCO) temperature.
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. 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 stopped when
CWCO is in effect and melting does not resume when the
temperature rises above the CWCO setting.