tekmar 662 Snow Detector & Melting Control - Manual (Page 3)

3
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
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
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.
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.
Power
Remote
Pump 1 Pump 2
Opening
Boiler
Warning
Closing
CWCO
Melting Idling
WWCO
Maximum
∆T
Maximum
Supply Minimum
Return
Water
If water is
detected the
Water light
turns on
Closing light is on
to turn off the
melting system
If a remote
signal is
present, the
Remote light
turns on
Note:
In Cold Weather Cut
Off, the CWCO light is
on and the WWCO
light is off
Pump 1 Pump 2
Opening
Boiler
Warning
Closing
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: Install the Snow/Ice Sensor 090 according to the instructions in Data Brochure D 090 and run the wiring back to the
base. See Data Brochure 090 for very important details on sensor location and installation.
• OR: Install the Slab Sensor 072 according to the instructions in the Data Brochure D 001 and run the wiring back to the base.
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.
Use a clean 120 V ac power source to ensure proper operation.
• 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.