tekmar 654 Snow Melting Control Installation - Manual (Page 30)

© 2013 654_D - 06/13 30 of 44
Warm Weather Shut Down
Cold Weather Cut Out
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 Set Temp menu that prevents
the control from entering Melt, Idle or Storm operation in order
to conserve energy. The control shows WWSD on the display
when WWSD is in effect.
Automatic (Auto)
The control enters WWSD when both the slab temperature
of a zone and the outdoor temperature exceed the Melt
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 Melt temperature 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 temperature during extremely
cold temperatures is not only expensive but may be impos-
sible 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 Out (CWCO) temperature
and the slab is below freezing. This is a safety and energy
saving measure. The control shows CWCO 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. If an 090 or 094 is not installed,
melting is permanently stopped when CWCO is in effect.
Melting does not resume when the temperature rises above
the CWCO setting.
Away Scene
Scenes provide an easy way to save energy while away
on vacation, or override a programmable schedule when
plans change.
Away Key --------------------------------------- ---------------------------------------
This control includes an Away Key to quickly disable the
snow melting system, and when connected to a tekmarNet
®
system, can also turn down the heating temperature on all
thermostats and suspend heating the domestic hot water
tank to maximize energy savings. To turn on the Away Key,
go to the Scene menu.
To activate the Away scene, touch “Going Away” on the
screen.
Storm
Melt
Away
Press
Away
Select PERM (permanent) or a number of days using the
or arrow. Range is 1 to 180 days.
Press the home button to accept the setting or leave the
screen untouched for several seconds.
“Scene Away” is displayed on the home screen until the
number of days expires.
Touch “Cancel Away” to cancel at any time.
User Switch -------------------------------------- --------------------------------------
A User Switch may be used to activate the Away scene.
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Additional Scenes -------------------------------- --------------------------------
The snow melting control supports scenes 1 (normal) 2
(away) and 3 (unoccupied). Scene 3 disables the snow
melting system. When the tekmarNet
® system is set to
scene 4 through 8, the snow melting control remains in
scene 1.