tekmar 661 User Manual

- Data Brochure

Snow Detector & Melting Control 661

The tekmar Snow Detector & Melting Control 661 is a microprocessor-based control which

OUTSIDE

FC

Slab
Target Slab

Snow Detector and Melting Control 661

On/Off operation

Item

% Output

Usage (hours)

Time Remaining

To change between
°F and °C, press and
hold for 1 sec.

Power
Remote

CWCO

WWCO
Melting

Idling

Water

Pump

Heat
Warning

R

LR 58223

activates a snow/ice melting system based on signals received from a Snow/Ice Sensor 090
and an Outdoor Sensor 070. When the control is in melting mode, the slab is maintained at a
“Melting” temperature through an on/off output which operates a contactor for electric cables,
a boiler, an injection pump or an injection valve. When the control is not in melting mode, the
melt system can either be shut down or it can be maintained at an idle temperature for faster
response and improved safety. If a fault occurs in a sensor or its wiring, the control activates
a Warning contact.

D 661

06/94

Sequence of Operation pg. 2

Installation . . . . . . . . . . pg. 3

Settings . . . . . . . . . . . . pg. 5

Display Operation . . . . pg. 6

Accumulated

hours of use

Water is detected

by the sensor

% Heat Output

Minimum Time

to slab

Remaining

in melt sequence

Target Slab surface

temperature

Slab surface

temperature

Pump relay is

closed

Slab
Target Slab

LCD display

item select

Slab heating is on

The Snow/Ice Sensor is installed in a hostile environment.

Fault warning

Terminal Plugs

Output:

Melt relay closed

when control is

in melting mode

It should be cleaned and checked on a regular basis.

Snow Detector & Melting Control 661

Pulse Width Modulation

Use Nº 20 AWG or larger copper conductors rated for at least 75°C / 300V.

1

3

2

Warning

Melt

5

4

Power

N

Weather is warm enough,
no snow melting required

Control is in

Melting mode

OUTSIDE

FC

% Output

Usage (hours)

Time Remaining

To change between
°F and °C, press and
hold for 1 sec.

Item

78

6

Pump

L

120 V ac power

9

10

Heat

supply is on

Power
Remote
WWCO
Melting
Water

Pump

Heat
Warning

R

LR 58223

NRTL/C

Remote Enable

Signal present

CWCO
Idling

Do not apply power here

12 13 141516 17

11

Blk

Red

Sen

Sen

Testing . . . . . . . . . . . . . pg. 6

Error Messages . . . . . . pg. 7

Technical Data. . . . . . . pg. 8

Limited Warranty. . . . . pg. 8

Control is in
Idling mode

Weather is too cold,

snow melting is off

Power

120 V ac ± 10% 50/60 Hz 20 VA

Relays

120 V ac 10 A 1/3 hp, pilot duty 240 VA 2 A

Enclosed Energy Management Equipment
Manufactured

in Canada by

44

Surface

Com
Sen

0.5

Rem

24

En

29°F

Off 35

Idling

2 hrs

Off

Min. On Time

18

Out
Sen

39°F

34

Melting

Test

Blu

Yel

Brn

Sen

Sen

Sen

3005678

20 80

Sensitivity

-20

Off

4

0694

50%

0°F

CWCO

Date
S/N

Desired slab surface
temperature during
Melting mode

Desired slab surface
temperature during
Idling mode

Sensor Sensitivity
to water

Test button to
initiate test
sequence

Cold Weather

25

Cut-off
temperature

Melting System
Minimum on time

H1077 1

Output:

Warning device

activated if sensor

fault detected

120 V ac

Power Supply

Turn on system pump

Output:

Output:

Turn on boiler

AND/OR

Output:

Turn on injection

pump

Output:

Turn on relay for

electric cables

1

Input: Outdoor

Input: Remote

Enable signal

(Optional)

Input: Snow/Ice Sensor 090 installed

with Sensor Socket 091

(Required)

Both of these components must

be ordered separately

Sensor 070

(Included)

IMPORTANT NOTE:

This control requires a Snow/Ice Sensor 090 and Sensor Socket 091. The Snow/Ice Sensor 090 is usually installed
prior to the installation of the control. The installer or designer should plan far enough ahead to allow ample time
for ordering and delivery. The Application Brochures A 661 provide a series of schematics which can be used with
this control. It is important that these applications together with the sequence of operation provided below are fully
understood in order to ensure that the control selected is compatible with its intended use.

Sequence of Operation

Powering up the control

After the Snow Detector & Melting Control 661 is powered up, the red status lights and the LCD segments are turned on for 7 seconds.
The control then displays the “OUTSIDE” temperature.

Melting Mode

Operation using a Snow/ Ice Sensor 090 - The control continually monitors the Snow/Ice Sensor 090.

When snow, ice or water is detected the water light turns on. If the control is not in WWCO or CWCO
(see below for an explanation of these terms), melting mode begins.

Operation using a Remote Enable - Melting mode can also be initiated if a remote enable signal is

present (terminals Com Sen and Rem Sen shorted together) and the control is not in WWCO or CWCO.
The remote enable is typically used with multiple Snow Melting Controls and Snow/Ice Sensors. It can
also be used to manually turn the melting system on by wiring a switch between the remote terminals.

Once the control is in melting mode, the Pump and Melting lights and the Pump and Melt relays are turned
on for at least the Minimum On Time set by the Min. On Time dial. The Heat relay is cycled on and off
to maintain the slab surface at the “Melting” temperature. The method used to cycle the heat relay is called
Pulse Width Modulation (PWM). More information on PWM is provided in Essay 000.

Idling Mode

When the 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 until melting is required. The Idling feature is also useful for preventing frost and light ice
formation. When the control is in idling mode, control operation is similar to melting mode except the
"Melting" light is off and the "Idling" light is on.

Warm Weather Cut Off (WWCO)

The 661 control can operate with or without an Outdoor Sensor 070. If an outdoor sensor is not used, the
control measures the “Outdoor” temperature using the Edge Sensor on the Snow/Ice Sensor 090. If the
“Slab” and “Outdoor” temperatures rise above the “Melting” temperature, the control shuts down the
melting system and enters Warm Weather Cut Off mode. The control remains in WWCO until the “Outdoor”
temperature drops below the “Melting” temperature. The control then continues with normal operation

.

The remote light is
on if a remote enable

Power

signal is present

Remote
WWCO

CWCO
Melting Idling
Water

Pump

The heat light

cycles on and off

Heat
Warning

Power
Remote

WWCO

CWCO
Melting Idling

Water

Pump

The heat light

cycles on and off

Heat
Warning

Power
Remote
WWCO

CWCO
Melting Idling
Water

Cold Weather Cut Off (CWCO)

Maintaining the slab at a “Melting” or “Idling” temperature in extremely cold weather 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
(measured using either the Outdoor Sensor 070 or the 090 Edge Sensor) drops below the “CWCO”
setting. The heater in the Snow/Ice Sensor 090 is kept on during CWCO until the control detects snow.
If snow is detected, the heater is turned off but the control retains the snow detected information. When
the “Outdoor” temperature rises above the “CWCO” temperature, the control exits CWCO and continues
with normal operation.

Warning Light and Relay

If a sensor fault occurs, the warning relay and light are turned on and an error message is given. The
lookup table provided on page 7 can be used to determine which sensor has the fault.

Exercising the pump

To prevent the pump from seizing during long WWCO periods, the
Pump relay is turned on for 20 seconds after every 3 days of no
operation. During exercising, the LCD screen alternates between two
special characters as illustrated in the diagram.

Slab
Target Slab

% Output

Usage (hours)

Time Remaining

2

Slab
Target Slab

Power
Remote
WWCO

CWCO
Melting Idling
Water

Pump

Heat
Warning

% Output

Usage (hours)

Time Remaining

Installation

Caution

Improper installation and operation of this control could result in damage to the equipment and possibly even personal
injury. It is your responsibility to ensure that this control is safely installed according to all applicable codes and
standards. This electronic control is not intended for use as a primary limit control. Other controls that are intended and
certified as safety limits must be placed into the control circuit.

Step One Getting ready

Check the contents of this package. If any of the contents listed are missing or damaged, please refer to the Limited Warranty
and Product Return Procedure on the back of this brochure and contact your wholesaler or tekmar sales agent for assistance.

Type 661 includes:

Other information available:

Read Application Brochures A 661 and select the correct Application for your job.

Note :This control must be installed with a Snow/Ice Sensor 090 and Socket 091. The Snow/Ice Sensor 090 and Socket 091

are not included with the type 661 and must be ordered separately.

Carefully read the details of the Sequence of Operation sections in all applicable brochures to ensure that you have chosen the
proper control and you understand its functions within the operational requirements of your system.

• One Snow Detector & Melting Control 661 • One Outdoor Sensor 070

• One Data Brochure D 661 • Application Brochures A 661 • One Data Brochure D 001

• Essay E 000 • Essay E 600

Step Two Mounting of the base

The control should be removed from its base by pressing down on the release clip in the wiring chamber and sliding upwards
on the control. The base is then mounted in accordance with the instructions in the Data Brochure D 001.

Step Three Rough-in Wiring

All electrical wiring terminates in the control base wiring chamber. It has standard 7/8" (22mm) knock-outs that accept common
wiring hardware and conduit fittings. Before breaking out the knock-outs, check the wiring diagram and select those sections of
the chamber with common voltages. Do not allow the wiring to cross over sections as safety dividers, installed later, prevent this.

Power should not be applied to any of the wires during the rough-in wiring stage.

• Install the Snow/Ice Sensor 090 according to the instructions in Data Brochure D 090 and run the wiring back to the base.

• Run the wiring from other system components to the base.

• Run the wiring from the 120 V ac source to the base.

• Multi-strand 16 AWG wire is recommended for the 120 V ac wiring due to its superior flexibility and ease of installation into
the terminal sockets.

Use a clean 120 V ac power source to ensure proper operation.

Step Four Electrical connection to the control

Power and output connections

6 7

•

The installer should test to confirm that no voltage is present at any of the wires.

• Install the control back into the base, sliding it down until it snaps into place.

• Connect the 120 V ac power supply to terminals

Melt Output

• Connect the melting system circuit to terminals
unpowered (dry) relay contact inside the control which closes when the control is in melting
mode. The most common devices to be turned on (enabled) by the 661 are pumps, heating
devices or other tekmar controls.

Warning Output

• If desired, connect a warning device to terminals
to a dry relay contact inside the control which closes when there is a sensor or wiring failure.

Caution:The 661 is an operating control and is not certified as a safety device. If safety

considerations are critical, a separate alarm system must be installed.

Pump Output

• Connect the System Pump to terminals
relay contact which closes when the control is in melting mode or idling mode.

Pump

Power N — Power L

Melt

(1 and 2). These terminals lead to an

Warning

(7 and 8). These terminals lead to a dry

(3 and 4). These terminals lead

(5 and 6).

5

Power

N L

1

Melt

1

Melt

5

Power

N L

2

2

6 7

8

Pump

34

Warning

34

Warning

8

Pump

Heat Output

• Connect the heating device circuit (electric cables, injection pump, injection valve, or
boiler) to terminals
closes when the control requires heat to be added to the slab.

Heat

(9 and 10). These terminals lead to a dry relay contact which

3

9

Heat

10