Service Manual

37 of 48 © 2015 680_D - 10/15
Melt – Manual Start and Timed Stop
The snow melting system can be started manually in one of
two different methods:
• Touch the Melt button on the control display.
•
The Melt/Stop Request parameter in the BACnet or Modbus
communication protocol.
Once manually started, the snow melting system continues to
operate until the time set by the Manual Melt Run Time setting
in the Setpoints menu elapses.
Push Melt button
BACnet or Modbus Melt Request
Manual Melt Run Time elapses
WWSD
Push Stop button
BACnet or Modbus Stop Request
CWCO
Timed
Melt
or
Idle
Off
If a manual start has been provided and a Snow/Ice Sensor
detects water, the control changes from manual melt to
automatic operation. The snow melting system will continue
to operate until the sensor is dry and the Additional Melt
Time elapses.
Tandem Snow/Ice Detection
The control allows any combination of two Snow/Ice sensors
090 or 094 or Snow Sensors 095 to be installed. This provides
full redundancy and increases the snow detection area.
Both sensors are used to detect snow or ice and if either
sensor is wet the snow melting zone starts melting. The
control continues to operate until both sensors are dry. This
allows snow or ice detection over a wider area. In the event
of a sensor failure, the control continues to operate normally,
giving building maintenance staff time to troubleshoot and
replace the faulty sensor if necessary.
Press Melt button to start melting operation