tekmar 662 User Manual

- Data Brochure

Snow Detector & Melting Control 662

The tekmar Snow Detector & Melting Control 662 is a microprocessor-based control which,

OUTSIDE

Supply Return Slab Boiler Return

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

Item

Snow Detector & Melting Control 662

Mixing Operation

Power

Remote

CWCO

WWCO

Idling

Melting

Maximum

Water

Target ∆T Actual ∆T % Output

∆T

Maximum

Minimum

Supply

Return

Pump 1

Pump 2

Closing

Opening

Boiler

Warning

LR 58223

NRLT/C

together with the Snow/Ice Sensor 090, activates and controls the rate of heat delivery to a snow melt system. This versatile control has three modulating outputs to control the heat delivery for most pump and/or valve arrangements. Protection of both the snow melt slab and the boiler is achieved through several safety features. Faster pick up times are also ensured through a viscosity compensation function which optimizes the rate of heat delivery to the slab during start up. The 662 combines all the necessary features to make snow melting safe and trouble free.

Sequence of Operation pg. 2

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

Settings . . . . . . . . . . . . pg. 7

Display Operation . . . . pg. 8

D 662

07/99

Testing . . . . . . . . . . . . . pg. 9

Error Messages . . . . . . pg. 10

Technical Data . . . . . . . pg. 12

Limited Warranty. . . . . pg. 12

Relative Energy

usage in ∆T x Hours

Boiler return temperature

Target slab ∆T

Actual slab ∆T

Supply temperature to slab

Slab surface temperature

Boiler pump is on

System pump is on

Valve is

opening/closing

LCD display

item select

Boiler operating

Fault warning

Output:

Melt relay is closed

when control is

in melting mode.

Output:

Warning relay is

activated if sensor

fault is detected

Water is detected

by the sensor

Current % Heat

Output to slab

Slab

Supply

Actual ∆T Target ∆T

The Snow/Ice Sensor is installed in a hostile environment. It should be cleaned and checked on a regular basis.

Snow Detector & Melting Control 662

Floating / Variable Speed / 4-20 mA

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

Warning

Melt

Slab is warm enough,

no snow melting is required

Snow detected:

control is in

Melting mode

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

Item

Com

Power

Pmp

OUTSIDE

% Output

Usage (∆T x hrs)

Boiler Return

Var

Pmp

Remote Enable

Signal present

1000Ω

1112131415

4-20

Boiler

+–

120 Vac power

supply is on

Power

Remote

WWCO

Melting

Water

Maximum Supply

Pump 1

Opening

Boiler

Warning

LR 58223

NRTL/C

Com

4-20

Opn

Mix

Control is limiting supply

temperature to Max.

Supply setting

Power System Pumps Variable Pump Mix Relays Other Relays Enclosed Energy Management Equipment

Manufactured

in Canada by

CWCO

Idling

Maximum ∆T

Minimum Return

Pump 2

Closing

18 19 202122 23

Cls

Red

Mix

Sen

39°F

34 44

Melting

Test

30°F

∆T Max.

Do not apply power here

Brn

Blu

Yel

Blk

Sen

Weather is too cold,

snow melting is off

Control is in Idling mode

120 V ac 50/60 Hz 300 VA 120 V ac 6 A 1/3 hp, pilot duty 240 VA 2 A 120 V ac 50/60 Hz 2.2 A 1/6 hp, internally fused 24 V ac 10 A, pilot duty 48 VA 2 A 120 V ac 10 A 1/3 hp, pilot duty 240 VA 2 A

29°F

Off 35

Idling

Surface

150°F

100 200

Max. Supply

0°F

-20

Off

CWCO

24 25

Com

Bret

Rem

Sen

Com Sen

27 28

Ret Sen

2094 1234567

50 %

20 80

Sensitivity

100°F

Off 150

Min. Boil Return

130 sec

Motor Speed /

Pump Response

Sup

Out

Sen

Control is limiting heat

output to Max ∆T setting

Control is maintaining

Min. boiler return temperature

Desired slab surface temperature during melting mode Desired slab surface temperature during idling mode

H11002

Input: Outdoor

Sensor Sensitivity to water

Test button to initiate test sequence

Maximum Supply temperature

Min. Boiler Return temperature

Max. Temperature drop across slab

Cold Weather Cut-off temperature

Motor Speed setting

Terminal Plugs

Sensor 070

(Included)

Date S/N

230

tekmar motor

Output: Turn on

system pump P1

Output: Turn on

boiler pump P2

120 Vac

Power Supply

Output:

operate pump at

varying speeds

Output:

Turn on boiler

Output: control 4-20 mA device

Output: control Floating Action

Input: System Supply Sensor 071

Input: System Return Sensor 071

Input: Boiler Return

Sensor 071

Input: Remote Enable

Signal.

Input: Slab Sensor 072

Detects slab temperature

Input: Snow/Ice Sensor 090 installed with Sensor Socket 091.

Both of these components must be ordered separately.

only. Does not detect Snow/Ice.

(Included)

(Optional)

(Included)

(Optional)

In order for this control to operate effectively, it must be installed in a well designed melting system. The Application Brochures A 662 provide a series of schematics which can be used with this control. Any deviations from these drawings must be discussed with a tekmar factory representative to ensure that system performance is not compromised. The application drawings are not final designs - each component within the system must be correctly sized for the control to operate effectively. It is important that the sequence of operation and the application drawings for this control are fully understood 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 662 is powered up, the red status lights and the LCD segments are turned on for 7 seconds. The control then displays the “Outdoor” temperature.

Melting Mode

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

090. When water is detected, the “Water” light turns on and if the control is not in WWCO or CWCO (see page 3 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 be also be used to manually turn the melting system on by wiring a switch between the remote terminals. A remote enable switch must be installed when a Slab

Opening light is on if the melting system requires more heat

Sensor 072 is used as this sensor cannot detect water.

Once the control is in melting mode, the Melting relay and boiler pump (relay P2 Pmp) are turned on. After a 4 second delay, the system pump (relay P1 Pmp) is turned on and after 8 seconds, heat is applied to the snow melt system through either a variable speed pump, a floating action mixing valve or a 4-20 mA device. The opening and closing lights indicate whether the control is increasing or decreasing the heat applied to the snow melt system. Essay E 021 compares the use of these devices for controlling the system temperature and also discusses the sizing and operation of the variable speed pump. Information on floating action can be found in Essay E 000. The 4-20 mA, variable speed pump and mixing valve outputs operate simultaneously. The 4-20 mA output can therefore be used to provide a remote readout of the pump or valve operation. The control remains in melting mode until no water is detected for at least 30 seconds and the slab is up to temperature for at least 30 minutes. Cold Weather or Warm Weather Cut Off can also terminate melting mode. When the control exits melting mode the boiler and system pumps are operated for an additional 90 seconds to purge the boiler. If the control switches from melting to idling mode, the boiler is not purged.

Idling Mode

When the melting system starts off 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” and “Water” lights are off and the “Idling” light is on.

Opening light is on if the melting system requires more heat

Snow melt system protection features

The 662 control has several features for protection of the snow melt system:

- to protect the slab from cracking due to thermal stresses, the control limits the rate of heat applied to the slab through a “∆T Max” setting. The ∆T represents the difference between the slab supply and return fluid temperatures which are measured by the control. If this temperature difference approaches the “∆T Max” setting, the “Maximum ∆T” light turns on and the control operates the valve or pump to maintain the ∆T at the “∆T Max” setting.

- to protect the piping and other components in the system, the control limits the supply temperature to a “Max. Supply” setting. When the melt system supply temperature approaches the maximum supply setting, the “Maximum Supply” light turns on and the control operates the valve or pump to reduce the supply temperature.

- to prevent the flue gases in the boiler from condensing, the control limits the boiler return temperature to a “Min. Boil. Return” setting. When the boiler return temperature approaches this setting, the “Minimum Return” light turns on and the control operates the valve or pump to increase the boiler return temperature.

∆T compensation for changes in fluid viscosity

Glycol solutions used in snow melt systems have widely varying viscosities between high and low temperatures. As the glycol solution temperature drops, viscosity increases causing a reduction in flow rate. This reduction in flow rate reduces the rate of heat output if the fluid temperature drop across the slab (∆T) remains constant. To compensate for this, the control increases the Maximum ∆T. This compensation is only applied when the fluid temperature is below 30°F, which is the temperature at which the viscosity of a typical 40% ethylene glycol / 60% water solution starts to increase significantly. The compensation feature is designed for fluids containing 40% ethylene glycol or 30 % propylene glycol; however, if the glycol percentage in the solution is lower than these values, the quality of heat regulation is not significantly affected. When the control is compensating for viscosity changes, the “Maximum ∆T” light flashes.

Ramping the ∆T during melting system start up

When the control turns on the melting system, the “Target ∆T” is slowly ramped up to the maximum ∆T to prevent thermal shock of the slab. If the temperature of the fluid returning to the boiler (source) is sufficient, the ramping time is less than 17 minutes. If the heat source is not dedicated to snow melting and there are other heat demands on the source, the ramping time may be longer.

Power

Remote

WWCO

Melting

Water

Maximum Supply

Pump 1

Opening

Boiler

Warning

Power

Remote

WWCO

Melting

Water

Maximum Supply

Pump 1

Opening

Boiler

Warning

If a remote signal is present, the Remote light turns on

CWCO

Idling

Maximum ∆T Minimum Return

Pump 2

Closing

Closing light is on if the melting system requires less heat

CWCO

Idling

Maximum ∆T Minimum Return

Pump 2

Closing

Closing light is on if the melting system requires less heat

Warm Weather Cut Off (WWCO)

If the “Slab” and “Outdoor” temperatures rise above the “Melting” temperature, heating the slab is no longer required. The control therefore shuts down the melting system and enters WWCO. During WWCO the “Closing” light remains on continuously and the heat supplied through the valve or variable speed pump is reduced to zero. When the “Outdoor” or “Slab” temperature drops below the “Melting” temperature, the control exits WWCO and continues with normal operation.

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 drops below the “CWCO” setting. During CWCO the “Closing” light remains on continuously and the heat supplied through the valve or pump is reduced to zero. The heater

If a remote signal is present, the Remote light turns on

If water is detected the Water light turns on

Power

Remote

WWCO

Melting

Water

Maximum Supply

Pump 1

Opening

Boiler

Warning

Note: In Cold Weather Cut Off, the CWCO light is on and the WWCO light is off

CWCO

Idling

Maximum ∆T Minimum Return

Pump 2

Closing

Closing light is o to turn off the melting system

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 if the Snow/Ice Sensor 090 detected snow during CWCO, the control initiates melting mode.

Warning Light and Relay

Pump 2

If a sensor fault occurs, the Warning relay and light are turned on and an error message is given. The look-up table provided on pages 10 and 11 can be used to determine which sensor has the fault.

Pump 1

Opening

Boiler

Warning

Closing

Exercising of the Pumps and Valves

To prevent the pumps or valves from seizing after long inactive periods, the pumps and valves are operated after every 3 days of no operation. The Pump P1 and Pump P2 relays are turned on for 20 seconds and the mixing valve or variable speed pump output is run fully open and/or fully closed. During exercising, the LCD screen alternates between two special characters as illustrated in the diagram.

Slab Supply Actual ∆T Target ∆T

% Output

Usage (∆T x hrs)

Boiler Return

Slab Supply Actual ∆T Target ∆T

% Output

Usage (∆T x hrs)

Boiler Return

Installation

Caution

Improper installation and operation of this control could result in damage to 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 662 includes:

• One Snow Detector & Melting control 662 • One Outdoor Sensor 070

• Three Universal Sensors 071 • One Slab Sensor 072

• One Data Brochure D 662 • Application Brochures A 662 • One Data Brochure D 001

Other information available:

• Essay E 021 • Essay E 000 • Essay E 600

Read Brochures A 662 and select the correct Application for your job.

Note: This control can be installed with EITHER a Snow/Ice Sensor 090 and Sensor Socket 091 OR a Slab Sensor 072. The

Snow/Ice Sensor 090 and Sensor Socket 091 are not included with the type 662 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 understand its functions within the operational requirements of your system.

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 all 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.

•

EITHER:

base.

•

OR:

See page 5 for very important details on sensor location and installation.

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

• Run 120 V ac to the power terminals on the control.

• 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.

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

See Data Brochure 090 for very important details on sensor location and installation.

Install the Slab Sensor 072 according to the instructions in the Data Brochure D 001 and run the wiring back to the base.

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

Step Four Electrical connections to the control

Power and output connections

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

• Install the control back into the base by sliding it down until it snaps in firmly.

• Connect the 120 V ac power supply to terminals

Melt Output

• Connect the melting device to terminals

Melt

(dry) relay contact inside the control which closes when the control enters melting mode. The most common devices to be enabled by the 662 are pumps, heating devices or other controls.

Warning

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

Caution

: The 662 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 Power Supply

• Terminal and

Com Pmp

P2 Pmp

(7) is the common power supply terminal for both terminals

(9).

• If the pumps P1 and P2 are operated from the same 120 V ac power supply as the control, connect the terminal

Power L (6)

to the terminal

• If a separate power supply is required for P1 and/or P2, contact tekmar for details.

System Pump P1

• Connect the System Pump to terminals

Power N — P1 Pmp

to a dry relay contact which closes when the control requires System Pump operation.

Boiler Pump P2

• Connect the Boiler Pump to terminals

Power N — P2 Pmp

to a dry relay contact which closes when the control requires Boiler Pump operation.

Variable Speed

• Connect the variable speed pump to terminals operated by this circuit must be permanent capacitor, impedance protected with a locked rotor current less than 2.2 amps. The Snow Detector & Melting Control 662 has an internal 2.5 amp fuse for overload protection.

This fuse is not field replaceable.

return and repair procedures if this fuse is blown.

Boiler

• Connect the boiler or the boiler control to the terminals

lead to a dry relay contact which closes when the control requires boiler operation.

4-20 mA Device

• Connect the positive 4 - 20 mA lead to terminal resistance allowed in the 4 - 20 mA circuit is 1000 Ω. The 4 - 20 mA output can be converted to a voltage output by connecting a resistor between terminals 13 and 14.

Power N — L

(5 and 6).

(1 and 2). These terminals lead to an unpowered

Warning

Com Pmp (7)

(3 and 4). These terminals lead to

(5 and 8). These terminals lead

(5 and 9). These terminals lead

Power N —Var Pmp

(5 and 10).

Contact tekmar for details on

Boiler

(11 and 12). These terminals

4-20 +

(13) and the negative 4 - 20 mA lead to terminal

P1 Pmp

Pumps

(8)

Boiler

Power N L

Power

N L

Power

N L

Power

N L

Power

N L

4-20

4 - 20 –

Com

Pmp

Melt

Com

Pmp

Com

Pmp

Com Pmp

Pmp

Com

4-20

Mix

–

(14). Maximum

Var

Pmp

Warning

Var

Pmp

Var

Pmp

Var

Pmp

Var

Pmp

1615

Opn

Cls

Mix

1413

4-20

–

4 - 20 mA

Actuating Motor

Connection to Operate

a 4 - 20 mA Device

Operate a 1 - 5 Vdc or 2 - 10 Vdc Device

1413

4-20

4-20 C

–

500 Ω resistor 4-20 mA converted to 2-10 Vdc output

250 Ω resistor 4-20 mA converted to 1-5 Vdc output

–

1-5 or 2-10 Vdc

Actuating Motor

Converting the 4 - 20 mA Output to

Floating Action Mixing Valve

• Connect one side (R) of a 24 V ac transformer to terminal

• Connect the (C) side of the transformer to terminal

N/C

Com Mix

(15).

on the tekmar 010 Actuating Motor.

For other makes of actuating motors, refer to the manufacturers' installation instructions.

• Connect the OPEN terminal of the Actuating Motor (CCW) to the terminal

Opn Mix

the control. This terminal leads to a relay contact which closes to provide 24 V ac to open the valve.

• Connect the CLOSE terminal of the Actuating Motor (CW) to the terminal

Cls Mix

the control. This terminal leads to a relay contact which closes to provide 24 V ac to close the valve.

(16) on

(17) on

4-20

–

66.5 Ω resistor

237 Ω resistor

0 - 135Ω "Slidewire"

Actuating Motor

Converting the 4 - 20 mA Output to Operate a 0 - 135Ω Actuating Motor

24Vac

4-20

–

Boiler

Separate Class II

Transformer

L N

Com

Mix

Opn

Cls

Mix

type 010

+ 8 hidden pages