tekmar 664 Snow Detector & Melting Control Installation - Manual (Page 7)

7 of 36 © 2009 D 664 - 07/09
• 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.
BOILER PROTECTION
Refer to Section A for a description of boiler protection.
BOILER OPERATION
Refer to Section C for a description of boiler operation.
Section C: Boiler Operation
Section C1: Boiler Supply Sensor
Section C1
Boiler Supply
Sensor
Section C2
Boiler Return
Sensor
Section C3
No Boiler
Sensor
BOILER SENSOR ON THE SUPPLY (Boil SENS = SUP)
When operating a boiler or boiler plant that is dedicated to a snow melting system, the 664
is designed to operate the boiler(s) as effi ciently as possible. The boiler(s) are cycled based
on the mixing supply fl uid temperature. This is to provide longer and more effi cient boiler
cycles. This mode of operation only works if the Boil SENS item is set to SUP.
BOILER MINIMUM (Boil MIN)
The Boil MIN is the lowest water temperature that the control is allowed to use as a boiler target temperature. If the boiler(s) is
operating, and the boiler supply temperature is near the Boil Min setting, the Minimum pointer turns on in the LCD while the Boil SUP
temperature is being viewed. If the installed boiler(s) is designed for condensing or low temperature operation, set the Boil MIN
adjustment to OFF.
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 at least one of the zones is either in the Melting or Idling mode.
The System Pump contact shuts off if the control is in CWCO, if both zones are in WWSD, or if there is no call for Melting or Idling.
ZONE OUTPUTS (Zn 1 and Zn 2)
The Zone 1 (Zn 1) contact and the Zone 2 (Zn 2) contact operate based on the Melting and / or Idling operation. Refer to Melting
Section E and / or Idling Section F for a description of how the zone contact(s) operate. The Zone Pump contact(s) shuts off if the
control is in CWCO, if the corresponding zone(s) is in WWSD, or if there is no call for Melting or Idling.
PURGE
The system pump (Sys P1) and zoning device(s) (Zn 1 and Zn 2) continue to operate for up to 2 minutes after the last demand is
removed. This purges the residual heat from the boiler(s) into the snow melting slab. If the boiler temperature drops below the Boil Min
setting after 20 seconds, the purge is aborted and the system pump and zoning device(s) are turned off.