Watts Tekmar Snow Melting Control 680

Snow Melting Control 680

The Snow Melting Control 680 is meticulously crafted to oversee electric or hydronic equipment, effectively eliminating snow or ice from various surfaces including driveways, walkways, business entrances, and more. It establishes communication with Building Automation Systems via BACnet® or Modbus® for alert notifications, remote monitoring, and adjustment capabilities. With the provision for up to two snow/ice sensors, it broadens the detection area and offers backup redundancy in case of sensor failure. Upon snow or ice detection, the 680 coordinates the operation of an electric heating cable, a single hydronic condensing or non-condensing boiler, or a steam valve to supply heat to the snow melt load. The 680 also ensures boiler return protection through the operation of a mixing valve or variable speed injection mixing. Additionally, monitoring of energy consumption is facilitated when connected to an optional flow sensor.

Key Features:

  • Automatic snow/ice detection, supporting both in-slab and retrofit aerial sensors, for prompt response to changing weather conditions.
  • Energy monitoring capability and BACnet or Modbus communication for efficient system management and monitoring.
  • Warm weather shut down and cold weather cut off functions for optimized performance and system protection.
  • Exercising feature ensures the continued functionality and reliability of the system.
  • Tandem snow/ice detection enhances accuracy and reliability in snow detection.
  • Idling capability for efficient operation during standby periods.
  • Storm feature optimizes system performance during severe weather conditions.
  • EconoMelt function manages energy consumption for cost-effective operation.
  • Slab protection feature ensures the durability and longevity of the system.


Agency Approvals CSA C US, meets class B: ICES & FCC Part 15, BTL Listed
Ambient Conditions Indoor use only, 32 to 122 degree F (0 to 50 degree C), less than 90 percent RH non-condensing
Analog Mixing Output 0-10 V (dc) 500 ohms min impedance / 4-20 mA 1 k ohms max impedance
Boiler Modulation Output 0-10 V (dc) 500 ohms min impedance / 4-20 mA 1 k ohms max impedance
Boiler Pump Relay 230 V (ac), 5 A, 1/3 hp
Boiler Stage Relay 230 V (ac), 5 A
Communications Type BACnet IP, BACnet MSTP, Modbus MSTP
Control Type Microprocessor control, this is not a safety (limit) control
Dimensions 8-1/16″ H x 11-1/8″ W x 2-15/16″ D (204 x 282 x 74 mm)
Display 3-1/4″ color touchscreen, 320 x 205 pixels
Enclosure Material PC+ABS plastic with steel conduit connection walls
Enclosure NEMA Rating NEMA 1
Floating Mixing Output 230 V (ac), 5 A
Flow Sensor 4-20 mA, 20 V (dc) power supply by control
Injection Mixing Pump 230 V (ac), 2.4 A
Power Supply 115 V (ac) plus / minus 10 percent, 60 Hz, 43 VA standby, 320 VA max
Pressure Sensor 0.5 – 4.5 V (dc) ratiometric, 10k ohms min load, 5 V (dc) power supply by control
Primary – System Pump Relay 230 V (ac), 10 A, 1/2 hp
Sensor NTC thermistor, 10 k ohms at 77 degree F (25 degree Cplus / minus 0.2 degree C) Beta =3892