tekmar 650 Snow Melting Control User Manual

Data brochure, D 650, Snow melting control 650

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Snow Melting Control 650

Pulse Width Modulation

On

Time

PRGM

F C

Item

5

System

Melt at power up

On

Off

6

3

4

Heat

7 8

9

Com

Sen

Slab

Sen

Out

Sen

2

1

C- R+

Power

Outdoor

Slab Sensor

Target Slab

Start

Stop

CWCO

Idling

Melting

Warm Weather Cut Off (WWCO)

If the control is in melting or idling mode and the “Slab” and “Outdoor” temperatures rise above the “Melting” temperature, the control

shuts down the melting system and enters Warm Weather Cut Off mode. During WWCO, the WWCO pointer flashes slowly. The
timer continues to run and normal operation is resumed when the “Outdoor” temperature drops below the “Melting” temperature.

Cold Weather Cut Off (CWCO)

Maintaining the slab at a “Melting” or “Idling” temperature in extremely cold conditions can be expensive and may even be
impossible. When it does snow at these colder temperatures, the snow is usually dry, light and less slippery. The control therefore
turns the melting system off when the “Outdoor” temperature drops below the “CWCO” setting. While the control is in CWCO, the
CWCO pointer flashes slowly. The timer continues to run until the slab temperature drops below the “Target Slab” temperature.
When the outdoor temperature rises above the “CWCO” temperature, the control exits CWCO and continues with normal operation.

On Time

The control has a built in timer which is used to set the length of time the control operates the system in melting mode. The timer begins
counting down when the snow melt system is turned on and the slab has reached the “Melting” temperature.

Powering up the Control

After the Snow Melting Control 650 is powered-up, the LCD
screen segments are turned on for 3 seconds. The control
then monitors and displays the outdoor temperature.

Melting Mode

The Snow Melting Control 650 is a manual control; in order to
start the melting system with the control powered up, the
“Start” button is pushed. The melt system can also be started
by setting the “Melt at power up” DIP switch to “On” and
powering up the control. When the control is in melting mode,
the melting pointer flashes slowly and the system relay is
turned on. The heat relay is cycled on and off to maintain the
slab at the “Melting” temperature. The method used to cycle
the heat relay is called Pulse Width Modulation (PWM). For
more information on PWM, see Essay 000. Once the slab has
reached the “Melting” temperature, a timer starts. The control
remains in melting mode until the timer “On Time” reaches
zero, the “Stop” button is pushed, or the remote switch is
turned off.
Note: If the remote switch is turned off and on again to restart

the system, the switch must be kept off for at least 1
second for the control to fully power down.

Idling Mode

When the snow melting system starts from a cold temperature,
the time required for the slab to reach “Melting” temperature
can be excessive. To decrease this start up time, the slab can
be maintained at an “Idling” temperature. The Idle feature is
also useful for preventing frost and light ice formation. When
the control is in idling mode, the idling pointer flashes slowly
and the system relay is turned on. The heat relay is cycled on
and off to maintain the slab at the “Idling” temperature.

- Data Brochure

Snow Melting Control 650

08/10

D 650

Sequence of Operation

°C or °F
indicators

Programming

mode

indicator

Item

identifiers

Wiring

Chamber

and

Terminals

Programming
and Melt
Start/Stop
buttons

Item

selection

and display

button

Hole for mounting screw

Hole for mounting screw

Temperatures
and On Time
display

The tekmar Snow Melting Control 650 is a microprocessor-based control that uses a Slab Sensor 072 and an
Outdoor Sensor 070 (both supplied with the control) to maintain a snow melt slab at a set surface temperature
during snow melting. When melting is not required, the melting system is either shut down or the slab is
maintained at an idling temperature for faster response and improved safety. The melting mode is initiated
manually by a button on the control or by an optional remote switch. Built in energy saving features include warm
and cold weather cut offs that automatically shut the melting system down in warm weather or extremely cold
conditions. The timer included in the control can be programmed to operate the snow melt system for a set time
period. Viewing and programming the operating parameters in either °C or °F is accomplished through a digital
LCD. The display indicates an error message whenever a sensor or its wiring develops a fault.

F

Snow Melting

Control 650

Pulse Width Modulation

On

Time

Item

Outdoor

Slab Sensor

Target Slab

Start

Stop

CWCO

Idling

Melting

Meets Class B:
Canadian ICES
FCC Part 15
Made in Canada
tektra 906-09

Power: 24 V (ac) ± 10% 50/60 Hz 3 VA

24 V (dc) ± 10% 0.03A

Relays: 240 V (ac) 10 A 1/3hp

H1113E

Dat

e Code

Signal wiring
must be rated
at least 300V

No power

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