Tekmar Snow Melting Control 680 User manual

Snow Melting Control 680
680_D
05/16
Snow Melting Replaces: 10/15
Installation & Operation Manual
1 of 48 © 2016 680_D - 05/16
Features
• BACnet or Modbus communication
• Automatic snow/ice detection
• Supports both in-slab and retrofit aerial sensors
• Tandem snow/ice detection
• Energy monitoring
• Idling
• Storm
• EconoMelt
• Warm weather shut down
• Cold weather cut off
• Slab protection
• Exercising
Introduction
The Snow Melting Control 680 is designed to operate electric or hydronic equipment to melt snow or ice from any surface
including driveways, walkways, business entrances, parking ramps, loading docks, hospital entrances, helipads and car
wash bays. It communicates with Building Automation Systems using BACnet® or Modbus® for alert notification, remote
monitoring and adjustment capability. The 680 uses a tekmar Snow/Ice Sensor 090 or a Snow Sensor 095 to automatically
detect snow or ice on the snow melting slab. Up to two snow/ice sensors can be installed, thereby increasing detection area
and providing backup redundancy in the case of sensor failure. Upon detection of snow or ice, the 680 operates electric
heating cable, a single hydronic condensing or non-condensing boiler, or a steam valve to provide heat to the snow melt
load. The 680 provides boiler return protection by operating a mixing valve or variable speed injection mixing. Monitoring
of energy consumption is possible when it is connected to an optional flow sensor.
BACnet is a registered trademark of ASHRAE. ASHRAE
does not endorse, approve or test products for
compliance with ASHRAE standards. Compliance of
listed products to the requirements of ASHRAE Standard
135 is the responsibility of BACnet International (BI).
BTL is a registered trademark of BI.

© 2016 680_D - 05/16 2 of 48
Table of Contents
Getting Started
Important Safety Information .............................................3
Installation .........................................................................4
Preparation .................................................................... 4
Packaging Contents ...................................................... 4
Physical Dimensions ..................................................... 4
Installation Location ....................................................... 4
Installing the Enclosure ................................................. 5
Servicing the Control ..................................................... 5
Rough-In Wiring ............................................................. 6
Sensor Wiring ................................................................ 7
Communication Wiring ................................................. 10
Control Wiring ............................................................... 11
Testing the Sensor Wiring ............................................ 14
Testing the Control Wiring ............................................ 14
Manual Override – Maximum Heat .............................. 15
Manual Override – Purge ............................................. 15
Manual Override – Test ................................................ 15
Manual Override – Off .................................................. 15
Switch Settings .................................................................16
Access Levels and Access Level Lock ........................ 16
User Interface ...................................................................17
Home Screen ................................................................ 17
System Operation ......................................................... 17
Symbols ........................................................................ 18
Help Screen .................................................................. 18
Status Menu Navigation ............................................... 18
Slab Status Screen ....................................................... 19
System Status Menu (1 of 2) ........................................ 20
System Status Menu (2 of 2) ........................................ 21
Settings Menu Navigation ............................................ 22
Setpoints Menu ............................................................. 23
Setup – System Setup Menu (1 of 2)............................ 24
Setup – System Setup Menu (2 of 2) ........................... 25
Setup – Boiler Setup Menu (1 of 2) .............................. 26
Setup – Boiler Setup Menu (2 of 2) .............................. 27
Setup – Mixing Setup Menu ......................................... 27
BAS Menu (1 of 2) ......................................................... 28
BAS Menu (2 of 2) ........................................................ 29
Monitor Menu (1 of 3) .................................................... 30
Monitor Menu (2 of 3) ................................................... 31
Monitor Menu (3 of 3) ................................................... 32
Toolbox Menu ............................................................... 33
Override Menu .............................................................. 34
Sequence of Operation ................................................... 35
Snow Melting Overview ................................................ 35
Melt Operation .............................................................. 35
Melt – Automatic Start and Stop .................................. 35
Melt – EconoMelt .......................................................... 36
Additional Melting Time ................................................ 36
Melt – Automatic Start and Timed Stop ....................... 36
Tandem Snow/Ice Detection ........................................ 37
Melt – Manual Start and Timed Stop ........................... 37
Idle Operation ............................................................... 38
Storm Operation ........................................................... 38
Slab Temperature Control ............................................ 38
Slab Protection ............................................................. 39
Warm Weather Shut Down ........................................... 39
Cold Weather Cut Off ................................................... 39
Snow Melt Zones and Priority ...................................... 39
Application Modes ........................................................ 40
Electric Operation ......................................................... 40
Pulse Width Modulation Zone Operation ..................... 40
Boiler Operation ............................................................ 41
Mixing Operation .......................................................... 42
Boiler and Mixing Operation ......................................... 42
Outdoor Sensor ............................................................ 42
Exercising ..................................................................... 42
Post Purge .................................................................... 42
Troubleshooting ............................................................... 43
Error Messages (1 of 4) ................................................ 43
Error Messages (2 of 4) ................................................ 44
Error Messages (3 of 4) ................................................ 45
Error Messages (4 of 4) ................................................ 46
Frequently Asked Questions ........................................ 47
Technical Data ................................................................. 48
Limited Warranty and Product Return Procedure ........... 48
Congratulations on the purchase of your new Snow Melting Control!
This manual covers the complete installation, programming and sequence of operation for this control. You will also find
instruction on testing, commissioning, and troubleshooting the control and system that it operates.

3 of 48 © 2016 680_D - 05/16
The installer must ensure that this control and its wiring are
isolated and/or shielded from strong sources of electromagnetic
noise. Conversely, this Class B digital apparatus complies
with Part 15 of the FCC Rules and meets all requirements of
the Canadian Interference-Causing Equipment Regulations.
However, if this control does cause harmful interference to
radio or television reception, which is determined by turning
the control off and on, the user is encouraged to try to correct
the interference by re-orientating or relocating the receiving
antenna, relocating the receiver with respect to this control,
and/or connecting the control to a different circuit from that
to which the receiver is connected.
Cet appareil numérique de la classe B respecte toutes les exi-
gences du Règlement sur le matériel brouilleur du Canada.
Radio Frequency Interference
Important Safety Information
It is your responsibility to ensure that this control is safely installed according to all applicable codes and standards. tekmar is
not responsible for damages resulting from improper installation and/or maintenance.
This is a safety-alert symbol. The safety alert symbol is shown alone or used with a signal word (DANGER,
WARNING, or CAUTION), a pictorial and/or a safety message to identify hazards. When you see this symbol
alone or with a signal word on your equipment or in this manual, be alert to the potential for death or serious
personal injury.
This pictorial alerts you to electricity, electrocution, and shock hazards.
This symbol identifies hazards which, if not avoided, could result in death or serious injury.
This symbol identifies hazards which, if not avoided, could result in minor or moderate injury.
This symbol identifies practices, actions, or failure to act which could result in property damage or damage to
the equipment.
Read manual and all product labels BEFORE using the equipment. Do not use unless you know
the safe and proper operation of this equipment. Keep this manual available for easy access by all
users. Replacement manuals are available at tekmarControls.com
• It is the installer’s responsibility to ensure that this control is safely installed according to all applicable codes and
standards.
•
Improper installation and operation of this control could result in damage to the equipment and possibly even personal
injury or death.
• This 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.
Do not attempt to service the control. There are no user serviceable parts inside the control. Attempting to service the control
voids the warranty.

© 2016 680_D - 05/16 4 of 48
Preparation
Tools Required -----------------------------------------------------------------------------------------
• tekmar or jeweler screwdriver
• Phillips head screwdriver
• Needle-nose pliers
• Wire stripper
Materials Required -------------------------------------------------------------------------------------
• 18 AWG LVT solid wire (low-voltage connections)
• 14 AWG solid wire (line-voltage connections)
• Four 1/8" - 1" wood screws
Installation Location
Installation
1234
Injection
Mixing
Pmp
46 47
N
Snow Melting Control 680
BAS, Boiler & Mixing
37 38
Mod
Boiler
33 34
Stage 1Stage 2
35 36
+
-
BACnet IP
Signal wiring must be
rated at least 300 V
For product literature:
www.tekmarControls.com
Meets Class B: Canadian
ICES & FCC Part 15
tektra 1070-01
Designed and
assembled in Canada
H7021B
Input Power:
115 V (ac) ±10%, 60 Hz, 320 VA
Primary, System Pump Relays:
230 V (ac), 10 A, 1/2 hp
Boiler Stage Relays:
230 V (ac), 5 A
Injection Mixing Pump:
230 V (ac), 2.4 A
Boiler Pump Relay:
230 V (ac), 5 A, 1/3 hp
Floating Action Mixing Output:
230 V (ac), 5 A
BluBrn /
Slab
25
Blk /
Com
26 27 28
Red
19
Brn /
Slab
20
Blk /
Com
Yel
21
Red
24
Blu
22
Yel
23
Snow / Ice Sensor 1Snow / Ice Sensor 2
Do Not Apply Power
41 42 43
Pwr
Floating
Action Mixing
ClsOpn
Boiler
39 40
Pump
Pump
29 30
Pump
Primary System
31 32 44 45
Power In
NL
BACnet MSTP
Modbus MSTP
16 17 18
Gnd
BA
RS-485
+–
20V
3
dc
5V
dc
Out
0-10V /
4-20mA In Out
Flow
Sensor
Pressure
Sensor
In
Vdc
6
Gnd
7
mA
45
+Com
8
Boil
Sup
Out
9
Boil
Ret
10
ComCom
11
Sys
Sup
12
Sys
Ret
13 14 15
+
1
Analog
Mixing
2
Temperature Sensors
+––
Disconnect All Power
Before Opening
Use supply wires suitable for at least 105°C
Employer des fils d’alimentation pour au moins 105°C
Do Not Apply Power
Physical Dimensions
Front View
8–1/16"
(204 mm)
2–15/16"
(74 mm)
Side View
8–1/16"
(204 mm)
11–1/8"
(282 mm)
7/16" (11 mm)
CL
7/16"
(11 mm) Ø 3/16"
(5 mm)
1/2" Knock-out
(x 16 back) (x 8 top)
(x 8 bottom) (x 2 side)
Choose the placement of the control early in the construction process to enable proper wiring during rough-in.
• Keep the control dry. Avoid potential leakage onto the control.
• Maintain relative humidity less than 90% in a non-condensing environment.
• Avoid exposure to extreme temperatures beyond 32-122°F (0-50°C).
• Install away from equipment, appliances, or other sources of electrical interference.
• Install to allow easy access for wiring, viewing, and adjusting the display screen.
• Install approximately 5 feet (1.5 m) off the finished floor.
• Locate the control near pumps and/or zone valves if possible.
• Provide a solid backing which the enclosure can be mounted to. Example: plywood or wall studs.
• Use the conduit knockouts provided on the upper, lower, back and sides of the enclosure for wiring.
Packaging Contents
The following are included in the product packaging:
• 1 Snow Melting Control 680
• 3 Universal Sensor 082
• 1 Outdoor Sensor 070
• 1 screwdriver
• 1 Application Brochure 680_A
• 1 Installation and Operation Manual 680_D
• 1 BAS Integration Manual 680_B

5 of 48 © 2016 680_D - 05/16
Installing the Enclosure
Servicing the Control
Injection
Mixing
Pmp
46 47
N
Signal wiring must be
rated at least 300 V
Designed and
assembled in Canada
44 45
Power In
NL
Disconnect All Power
Before Opening
Step 1
Disconnect the wiring terminal plugs
by pulling down in the lower wiring
chamber and by pulling up in the
upper wiring chamber.
Step 2
There are two tabs located on the
right side of the enclosure. Insert a
screwdriver into the top of the tab
and gently pry the tab away from the
control while pulling the control toward
you. Repeat for the second tab.
Step 3
Pull the control toward you.
Step 4
Disconnect the two wiring plugs and
remove the control.
Custom Panel
or Electrical Box
Wall or Panel Door
In the event that the control requires servicing or
replacement, the control can be easily removed from
the enclosure. This allows all wiring and conduit to
remain installed.
Step 5
The new control is now ready to be
installed in the reverse order.
• Install the control enclosure to a wall or to an electrical box.
•
Three wiring chamber dividers are included. The dividers
provide a barrier to keep low voltage wiring separated from
line voltage wiring.
•
If the dividers are not used, then low voltage circuits must
use wire rated at least 300 V.
To prevent the risk of personal injury
and/or death, make sure power is not
applied to the control until it is fully
installed and ready for final testing.
All work must be done with power to
the circuit being worked on turned off.
Please be aware local codes may require this
control to be installed or connected by an electrician.

© 2016 680_D - 05/16 6 of 48
Rough-In Wiring
Low-Voltage Wiring -------------------------------------------------------------------------------------
Pull two conductor 18 AWG LVT cable, up to 500 feet
(150 m) long, for the following equipment:
• Outdoor temperature sensor
• System supply sensor
• System return sensor
• Boiler supply sensor
• Boiler return sensor
• Single-stage on/off boiler
• Modulating boiler 0-10 V (dc) or 4-20 mA
•
Mixing valve or mixing injection pump using a 0-10 V (dc)
or 4-20 mA signal
• Flow sensor
Pull three conductor 18 AWG LVT cable, up to 500 feet
(150 m) long, for the following equipment:
• Mixing valves using a floating action signal
• Pressure sensor
Pull four conductor 18 AWG LVT cable, up to 500 feet
(150 m) long, for the following equipment:
• Snow Sensor 095
• Two-stage on/off boiler
Pull the Snow/Ice Sensor 090 or 094 cable to the control.
Line-Voltage Wiring ------------------------------------------------------------------------------------
Pull two conductor 14 AWG cable, up to 500 feet
(150 m) long, for the following equipment:
• System pump
• Primary pump
• Boiler pump
To prevent the risk of personal injury and/or death, make sure power is not applied to the control until it is fully
installed and ready for final testing. All work must be done with power to the circuit being worked on turned off.
Please be aware local codes may require this control to be installed or connected by an electrician.
• Install the supplied wiring compartment barriers by sliding them into the grooves provided to isolate the low and line-
voltage wiring.
• Strip all wiring to a length of 3/8 in. or 10 mm for all terminals.
• A circuit breaker or power disconnect that provides power to the control should be located nearby and clearly labeled.
• Refer to the current and voltage ratings at the back of this manual before connecting devices to this control.

7 of 48 © 2016 680_D - 05/16
Sensor Wiring
20V
3
dc
Out In
+
4
mA
Flow
Sensor
An analog flow sensor can be connected to the control to provide flow and energy monitoring. The control
supports a 4-20 mA style sensor. Examples of compatible aftermarket flow sensors include:
• Kele SDI series
• Kele 200 series with 310 transmitter
• Kele 2200 series
• Kele 3100 series
• Omega FV100 series
• Omega FV-500C series
• Omega FTD-40 series
• Omega FTD-47 transducer
Using the system supply sensor and the boiler return sensor, energy output can be calculated and displayed
from the flow measurement. The control provides a 20 V (dc) powered output to the flow sensor.
• Connect the power input on the flow sensor to the 20 V dc Out terminal 3.
• Connect the signal return wire to mA (+) In terminal 4.
5V
dc
Out
Pressure
Sensor
In
+
6
Vdc
-
7
Gnd
5
An analog pressure sensor can be connected to the control to provide water pressure monitoring.
The control supports a 0.5-4.5 ratio metric V (dc) style pressure sensor. Examples of compatible
pressure sensors include:
• Honeywell PX2 (AA) series
• Measurement Specialties 7100 series
To connect the pressure sensor to the control:
• Connect one wire from the power supply (+5 V dc) on the pressure sensor to the 5V dc Out ter-
minal 5.
• Connect one wire from the pressure sensor signal output to the Vdc (+) In terminal 6.
• Connect one wire from the GND (0V) on the pressure sensor to the Gnd (-) terminal 7.
Wiring the Flow Sensor ---------------------------------------------------------------------------------
Wiring the Pressure Sensor ----------------------------------------------------------------------------
Wiring the Analog Mixing Output -----------------------------------------------------------------------
The control can operate a mixing valve by providing a 0-10 V (dc) or a 4-20
mA signal to the valve actuating motor.
• If applicable, connect the mixing actuator positive (+) to terminal 1.
• If applicable, connect the mixing actuator negative (-) to terminal 2.
+
1
0-10V /
4-20mA
−
2
Analog
Mixing

© 2016 680_D - 05/16 8 of 48
Mounting the Outdoor Sensor --------------------------------------------------------------------------
• Connect 18 AWG or similar wire to the two terminals provided
in the enclosure and run the wires from the outdoor sensor
to the control. Do not run the wires parallel to telephone or
power cables. If the sensor wires are located in an area
with strong sources of electromagnetic interference (EMI),
shielded cable or twisted pair should be used or the wires
can be run in a grounded metal conduit. If using shielded
cable, the shield wire should be connected to the Com or
Com Sen terminal on the control and not to earth ground.
•
Follow the sensor testing instructions in this manual and
connect the wires to the control.
• Replace the front cover of the sensor enclosure.
Wiring the Outdoor Sensor -----------------------------------------------------------------------------
The Universal Sensor 082 is designed to mount on a pipe or in a temperature
immersion well. The sensor should be placed downstream of a pump or after
an elbow or similar fitting. This is especially important if large-diameter pipes
are used as the thermal stratification within the pipe can result in erroneous
sensor readings. Proper sensor location requires that the fluid is thoroughly
mixed within the pipe before it reaches the sensor.
Strapped to Pipe
The Universal Sensor can be strapped directly to the pipe using the cable tie
provided. Insulation should be placed around the sensor to reduce the effect
of air currents on the sensor measurement.
Mounting the Boiler and System Sensors --------------------------------------------------------------
• The 070 can be mounted directly onto a wall with the wiring
entering through the back or bottom of the enclosure. Do
not mount the 070 with the conduit knockout facing upwards
as rain could enter the enclosure and damage the sensor.
• In order to prevent heat transmitted through the wall from
affecting the sensor reading, it may be necessary to install
an insulating barrier behind the enclosure.
•
The 070 should be mounted on a wall which best represents
the heat load on the building (a northern wall for most build-
ings and a southern facing wall for buildings with large south
facing glass areas). The 070 should not be exposed to heat
sources such as ventilation or window openings.
• The 070 should be installed at an elevation above the ground
that will prevent accidental damage or tampering.
Remove cover
by sliding
upwards away
from the base.
To wire from
the back,
remove the
knock-out in
the sensor
base.
S1
S1
If using
conduit,
remove the
flexible plug
from the base
bottom.
S1
S1
Attach the
base to the
wall, soffit
or electrical
box.
S1
S1
Wires from
outdoor sensor
and sensor
common
terminals on
tekmar control
S1
S1
Slide cover back
over base

9 of 48 © 2016 680_D - 05/16
No Power
Boil
Sup
Com
8910
Boil
Ret
The boiler return sensor is only used when a mixing valve or variable speed
injection mixing is installed. The boiler return sensor protects the boiler from
cold return water temperatures.
• If applicable, connect the boiler return sensor to terminals 8 and 10.
Wiring the Boiler Return Sensor ------------------------------------------------------------------------
Mounting the System Supply Sensor -------------------------------------------------------------------
The system supply sensor is used in most hydronic applications except
when only operating a boiler.
• If applicable, connect the system supply sensor to terminals 11 and 12.
No Power
Sys
Sup
Com
11 12 13
Sys
Ret
The system return sensor is used in conjunction with the flow sensor to
determine energy consumption. If applicable, connect the system return
sensor to terminals 11 and 13.
Wiring the System Return Sensor ----------------------------------------------------------------------
Mounting the Boiler Supply Sensor --------------------------------------------------------------------
The boiler supply sensor is used when operating a boiler.
• If applicable, connect the boiler supply sensor to terminals 8 and 9.
No Power
Boil
Sup
Com
8910
Boil
Ret
No Power
Sys
Sup
Com
11 12 13
Sys
Ret
Bottom of
Enclosure 080
Universal
Sensor Cable Tie
Sensor Well
Retaining
Clip
Universal
Sensor
Immersion Well
If a Universal Sensor is mounted onto 1" (25 mm) diameter L type copper pipe,
there is approximately an 8 second delay between a sudden change in water
temperature and the time the sensor measures the temperature change. This
delay increases considerably when mild steel (black iron) pipe is used. In general,
it is recommended that a temperature well be used for steel pipe of diameter
greater than 1-1/4" (32 mm). Temperature wells are also recommended when
large diameter pipes are used and fluid stratification is present.
Conduit Connection
The Universal Sensor and Universal Sensor Enclosure 080 (sold separately) are
specifically designed to mount onto a 3/8" (10 mm) ID temperature well that is
supplied with an end groove. To install the well, plumb a tee into the pipe and fix
the well into the tee. The 080 enclosure has a 7/8" (22 mm) back knockout that
must be removed and fitted over the temperature well. The universal sensor is
then inserted into the well and the retaining clip supplied with the enclosure is
snapped onto the well end groove. If the well has a threaded end, the installer
must supply a standard threaded conduit retaining ring. The two wires from the
sensor are connected to the terminal block provided in the enclosure. The other
side of the terminal block is used to connect wires from the control.

© 2016 680_D - 05/16 10 of 48
Communication Wiring
A Building Automation System (BAS) can be connected to the control for
remote monitoring and adjustment capability. BACnet IP communications
use an ethernet CAT-5E or CAT-6 cable. The maximum recommended cable
length for CAT-5E is 150 feet (45 m) and 300 feet (90 m) for CAT-6.
•
Connect the Ethernet RJ45 plug on the BACnet IP network to the
ethernet RJ45 jack on the 680.
A Building Automation System (BAS) can be connected to the control for remote
monitoring and adjustment capability. BACnet MS/TP and Modbus communications
use an RS-485 connection. Use 18 AWG twisted shielded pair cable. The maximum
cable length is dependent on the baud rate and whether terminating resistors are
installed. Refer to the BAS Integration Manual 680_B for details on the maximum
recommended cable length.
• Connect the B (+) terminal on the BAS network to the RS-485 B (+) terminal 16.
• Connect the A (-) terminal on the BAS network to the RS-485 A (-) terminal 17.
• Connect the ground (G) terminal on the BAS network to the Gnd terminal 18.
RJ45
BACnet
Network
Snow Melting
Control 680
BAG
Master
680
16 17 18
Gnd
+–
RS 485
BA
(+) (-)
BACnet MS/TP and Modbus Communication -----------------------------------------------------------
BACnet IP Communication -----------------------------------------------------------------------------
Snow/Ice Sensor ---------------------------------------------------------------------------------------
Up to two Snow/Ice Sensor 090 or 094 can be connected to the control. The
090 has a 65' (20 m) cable and the 094 has a 208' (63 m) cable. The cable may
be extended to a total length of 500' (150 m) using 18 AWG cable. Any junction
boxes must kept dry.
If the Snow/Ice Sensor 1 input is used:
• Connect the brown wire to terminal 19.
• Connect the black wire to terminal 20.
• Connect the blue wire to terminal 21.
• Connect the yellow wire to terminal 22.
• Connect the red wire to terminal 23.
If the Snow/Ice Sensor 2 input is used:
• Connect the brown wire to terminal 24.
• Connect the black wire to terminal 25.
• Connect the blue wire to terminal 26.
• Connect the yellow wire to terminal 27.
• Connect the red wire to terminal 28.
Brn/
Slab
19
BluBlk/
Com
20 21
Yel
22
Red
23
Snow/Ice Sensor 1
Brn/
Slab
24
BluBlk/
Com
25 26
Yel
27
Red
28
Snow/Ice Sensor 2