tekmar 665 Snow Detector & Melting Control Installation - Manual (Page 5)

5 of 28 © 2012 D 665 - 04/12
RUNNING TIME (RUN TIME)
The running time is the length of time that the system operates once it has reached its slab target temperature. During the time that
the system is approaching its slab target temperature, the RUN TIME does not decrease. Once the system reaches its slab target
temperature, the RUN TIME begins counting down. When the RUN TIME reaches 0:00 as displayed in the Status item in the VIEW
menu, the system has finished melting.
Note: The running time is only applicable when a manual melting enable signal starts the snow melting system. Refer to Section C1 for
a description of a manual melting enable.
STATUS (STATUS)
While in the VIEW menu there are a number of items available to determine the current status of the system. To view the current
status of the system, select the STATUS item in the VIEW menu.
• STRT The word STRT is displayed after the snow melting system has been manually enabled. It is displayed until the
zone reaches its slab target temperature. If the zone is at its slab target temperature, STRT is displayed for fi ve
seconds after the snow melting system has started operation. This is to verify that the control has entered into the
Melting mode.
• STOP The word STOP is displayed for fi ve seconds after the snow melting system has been manually disabled. The
word STOP is also displayed if either a Remote Start / Stop Module 039, Remote Display Module 040 or the Stop
on the control stops the snow melting system and an external melt demand is still present.
• IDLE The word IDLE is displayed as long as the zone is operating at its idling temperature.
• “IDLE” The word IDLE is fl ashed on the display as long as the zone is operating in temporary idle.
• EXT The word EXT is displayed when the RUN TIME has reached 0:00 and the control still has an external melt demand.
In this situation, the zone continues melting until the melt demand is removed or the control is stopped.
• DET The word DET is displayed after the snow melting system has been automatically enabled by the
Snow / Ice Sensor 090 and the zone is at its slab target temperature. DET is also displayed once the control is
manually enabled after automatic detection by the 090 and the running time has counted down to 0:00.
• 0:00 to 23:59 hr While the zone is up to temperature and melting, the remaining RUN TIME is displayed.
• INF If an infi nite RUN TIME is selected and the zone is melting, INF is displayed.
• WWSD When the zone is in Warm Weather Shut Down, WWSD is displayed.
• CWCO When the control is in Cold Weather Cut Out, CWCO is displayed.
Cycle (20 minutes)
Relay On Time Relay Off Time
Relay On Time Relay Off Time
Relay On Time
Less Heat
More Heat
SNOW MELTING OVERRIDE
If the AWAY setting is selected in the SCHEDULE menu, the snow melting system is shut
down. Both the Melting and Idling temperatures are ignored as long as the control remains
in the Away mode.
SYSTEM PUMP OPERATION (SYS P1)
The system pump (Sys P1) contact closes and remains closed as long as the system is either in the Melting or Idling mode. The
system pump contact shuts off if the control is in CWCO, WWSD, or if there is no call for Melting or Idling.
HEAT CONTACT OPERATION
The control uses the Heat contact to control the temperature of the slab.
When the control is either Melting or Idling, the Heat contact operates
on a 20 minute cycle. If the slab requires more heat, the on time in each
cycle is increased. If the slab requires less heat, the on time of each
cycle is decreased. The Heat contact shuts off if the control is in Cold
Weather Cut Out (CWCO), Warm Weather Shut Down (WWSD), or if
there is no call for Melting or Idling.
MELTING CONTACT OPERATION
The Melting contact (terminals 13 and 14) closes and remains closed as long as the system is in the melting mode. This contact
can be used as an external signal to indicate that the system is currently in the melting mode. This contact can also be used as a
means of prioritizing or enabling multiple snow melting controls.
PURGE
The system pump (Sys P1) and zoning device continue to operate for 20 seconds after the last demand is removed. This purges
the residual heat from the boiler(s) into the snow melting slab.