Tekmar 1873-ESM Guide

Ice and Snow Detector
1873-ESM, Single Unit Configuration
Installation and Adjustment Instructions

2
Content
Overview......................................................4
Terms and functions...................................6
Installation and commissioning .............. 10
Connection diagram ......................................11
Required settings...........................................12
Further basic settings ....................................12
User interface............................................ 14
Settings...................................................... 21
Troubleshooting........................................ 31
Technical data........................................... 37
Available accessories............................... 40
Important note:
This documentation only contains information
related to the Ice and Snow Detector 1873 in the
“Single Unit” configuration.
For the “System” and “Multi Channel” configu-
rations, refer to the complete documentation
“Ice and Snow Detector 1873-ESM and 1875-
ESM” (ME-1873~5-ESM-EN).
Safety instructions
Always observe the attached safety instructions and
the general regulations for electrical installation dur-
ing installation and operation of the device!

3
Scope of delivery
Ice and Snow Detector
1873-ESM
Installation and Adjustment In-
structions:
Ice and Snow Detector 1873,
Single Unit Configuration
Safety instructions
tekmar pencil
(Rubber end can be used to operate
the touch display)

4
Overview
Tekmar ice detection systems use their combi sen-
sors to measure temperature and moisture in
heated outdoor areas such as open spaces, roofs
and gutters. This means that they operate in a par-
ticularly energy-efficient way, since the heating is
only switched on when it is cold or if there is water,
ice or snow.
The 73 ice detection system is an all-round system
wherever it is necessary to keep an area free of ice
and snow: It is flexible, maintenance-free and inex-
pensive. It can be modularly extended to form a
multi-channel system and can be used in a cloud
environment or in building management systems.
All system 73 control devices are easy to install and
commission. They are characterised by intelligent
factory settings and a straightforward commission-
ing function. The sensors and the control units can
be freely combined so that the system can be opti-
mally adapted to the operating conditions. All con-
trol units are designed for one combi sensor and
one heating circuit.
Ice and Snow Detector 1873-ESM
The Ice and Snow Detector 1873 is a single-
channel device that can be used for all applications
in the field of ice and snow detection.
It is operated and adjusted via an illuminated touch
graphic display, which is also used to set the para-
meters of all the other devices in a system. A three-
level password protection is available for the multi-
lingual menu.
A comprehensive alarm management checks both
the internal device functions and those of the con-
nected sensors. Furthermore, the function of the
heating relay and a downstream contactor can be
monitored.
Sensors
The System 73 sensors use a measuring principle
based on the thermal capacity of the sensor surface
and the water on it, possibly in the form of ice or
snow. This measuring principle was developed by
tekmar and has already proven itself over many
years. Only one sensor is required to measure
moisture and temperature, making installation very
simple and cost-effective.
System 73 offers two types of sensors: The 3356
sensor is ideally suited for installation in open
spaces such as roads, walkways or staircases. The
3354 sensor can be mounted, for example, in
gutters and on roof surfaces thanks to its design

Overview
5
with axial cable connection. Both sensors are
characterised by a compact and robust design,
which is achieved by the casing made of high-
quality, corrosion-resistant brass and the microbe-
proof, longitudinally watertight cable.
The sensors can be used for a wide variety of re-
quirements due to the comprehensive range of
accessories for their installation and mounting. This
also optimises installation and maintenance costs.
Documentation
Other relevant documentation:
Safety instructions
I-187x-ESM-Sensor-EN,
summarised extract from M-MES-Sensorik
(Installation instructions for sensors of the T,
TF-E und TF-S systems, available in German
only)

6
Terms and functions
Ice detection channel
An ice detection channel is a unit consisting of a
heating circuit with its output relay, a combi sensor
and the associated evaluation logic.
Functions of an ice detection channel:
control and monitoring of one sensor and one
heating circuit
continuous temperature monitoring in the
heated area
activation of the moisture measurement if the
temperature falls below the activation tempera-
ture
start of the minimum heating time if the
moisture threshold is exceeded on the sensor
(alternatively triggered by an external signal at
the control input)
deactivation of the heating if the temperature
falls below the switch-off temperature (lower
temperature limit)
monitoring of the heating circuit output for inter-
ruptions in the heating circuit and internal faults
of the relay
Operating mode
The basic operation of an ice detection channel can
be selected via the operating mode.
Temp. Moisture
This is the normal operating mode of an ice de-
tection channel. In this mode the temperature
must first fall below the activation point, and a
sufficiently high moisture measurement then ac-
tivates the heating circuit.
Temperature
In the temperature mode, only the tem-
perature is measured but not the
moisture. The heating will be active if the tem-
perature of the heating area is below the activa-
tion temperature.
Emergency mode
In addition to the automatic activation of
the emergency mode, it can also be acti-
vated manually in the event of malfunctions
around the system. Also refer to the explana-
tions under "Emergency mode" on page 8.
Off
The ice detection channel is switched off.

Terms and functions
7
Activation temperature (upper temperature limit)
If the temperature of the combi sensor - and thus of
the heated area - falls below the defined activation
temperature, the moisture measurement will be ac-
tivated and, if necessary, the heating circuit will be
switched on. If the temperature rises above the ac-
tivation temperature, an activated heating circuit will
be switched off and the moisture measurement will
be deactivated.
Moisture threshold
The moisture threshold can be used to adjust the
sensor's sensitivity with regard to the detection of
water, ice or snow on the sensor. The moisture
threshold can be set within a range of 0.5 to 9.5.
Low values mean high sensitivity.
The basic setting for the moisture threshold should
be 1 to 2 points above the dry value indicated on
the sensor. If no information is available on the
sensor, a test measurement can be triggered via
the menu when the sensor is dry and the deter-
mined value can be used as the dry value.
If the system switches the heating system on too
early, i.e. if there is very little moisture or the sensor
is dry, the moisture threshold should be increased.
If the system switches on the heating system too
late, the moisture threshold should be reduced.
Note: If the moisture threshold is too low, the
heating system may be permanently activat-
ed during times when the temperature is below the
activation temperature. This can lead to an in-
creased energy consumption. In general: the lower
the moisture threshold, the higher the energy con-
sumption.
Moisture measurement
Below the activation temperature, the moisture
measurement is repeated at regular intervals until a
moisture value above the moisture threshold is de-
tected or until the activation temperature is exceed-
ed again. If moisture is detected, the heating circuit
switches on for the minimum heating time and the
moisture measurement is suspended. Only after the
minimum heating time has elapsed is the moisture
determined again at regular intervals. Depending on
the result of the moisture measurement, the heating
circuit remains switched on or is deactivated.

Terms and functions
8
The system automatically optimises the duration of
a measuring cycle depending on the sensor type
and temperature.
Switch-off temperature (lower temperature limit)
In addition to the activation temperature, there is
also a lower temperature limit (the switch-off tem-
perature), below which the moisture measurement
and, if necessary, the heating are deactivated
again.
At very low outside temperatures, dripping conden-
sation no longer occurs in roof areas and snowfall is
no longer to be expected in open spaces. (If snow
falls, it will be dry, light and not slippery. Since in
this case the heating capacity is often not sufficient
to completely defrost the surface and it would only
be partially thawed instead, the risk of slipperiness
would be rather increased by switching on the heat-
ing system.)
Minimum heating time
If moisture above the moisture threshold is detected
after the temperature has fallen below the activation
temperature, the minimum heating time starts,
which ensures that the heated area is definitely de-
frosted. During the minimum heating time, no fur-
ther moisture measurement takes place.
An external button on input A, which is switched to
L, can be used to manually activate the defined
minimum heating time. When the button is pressed
once, the heating is switched on for the duration of
the minimum heating time.
Follow up time
After the monitored area has thawed and dried with
the help of the heating, i.e. when the combi sensor
no longer detects moisture, a follow up time can be
activated. In the event that the combi sensor cannot
be optimally positioned, the follow up time can be
used to ensure that any ice and snow residues are
also defrosted, e.g. in shaded areas.
Emergency mode
In the emergency mode the heating circuit output is
activated with a PWM (pulse width modulation) be-
haviour (adjustable interval time and duty cycle).
The emergency mode can either be activated man-
ually via the operating mode or automatically if
there is a temperature error in the combi sensor.

Terms and functions
9
In case of an error in the combi sensor additionally
an alarm will be triggered. If only the moisture unit
is affected by the sensor error, the emergency
mode will only be activated if the temperature is
below the activation temperature. If the temperature
unit is also defective, the emergency mode will be
activated independently of the outdoor temperature,
but only if this has been explicitly enabled in the
menu.
Note: The emergency mode should only be
activated if the alarm can be registered cen-
trally. An unnoticed emergency mode can possibly
lead to extreme energy consumption.
Heating circuit monitoring
The heating circuit connected to the heating circuit
relay is monitored for interruptions and the heating
relay itself for malfunctions. The heating circuit is
monitored when switched off. An interruption of the
circuit results in an alarm message.
Note 1: When using a contactor to increase the
switching capacity, only the contactor is monitored,
not the heating circuit connected to it.
Note 2: The switching output for relay R1/R2 must
be operated at 230 V to detect a switching output
error. When using a lower voltage (e.g. 24 V DC),
this function is not guaranteed and an error mes-
sage may occur.
Alarm management
The alarm management of the 1873 monitors the
sensor and heating circuit output for fault condi-
tions. A detected error is reported via the display
and the alarm relay.
Functions of alarm management:
monitoring of the ice and snow detector, the
sensor and the heating circuit output
adjustable alarm delay
forwarding of an alarm via the alarm relay
Alarm relay
The alarm relay is designed as a change-over con-
tact and can therefore be used for both open-circuit
and closed-circuit alarm circuits. By inverting the
alarm relay in the menu, a power failure can also be
reported (alarm inverted and signal loop via the
normally open/change-over contact).
Due to its insulation, the alarm relay can be used
for both mains voltage and SELV circuits.

10
Installation and commissioning
Proper use
The device must only be used for the control
of electric and water-operated heating
systems. It has to be installed in an electric distribu-
tor (fuse box or control cabinet) and connected to
the existing heating system. When doing so, it is
absolutely necessary to observe all Technical data.
Any different or improper use of the device may
cause defects in the device and/or life-threatening
states and situations. Additionally all guarantee
claims are forfeited in such a case.
Installation procedure
Only qualified personnel (electrician or
similar qualification) may install the device.
The relevant engineering practices and the
enclosed safety instructions must be observed!
Disconnect the control cabinet before installation.
Mount the device on a 35 mm mounting rail in a
subdistribution unit or another adequate housing.
Wire it according to the following illustration.
Protection against contact according to protection
class II is guaranteed by the following measures:
Installation in small distribution board according to
DIN 57603/VDE 0603 (e.g. distributor of the N-
system)
or
DIN 57659/VDE 0659
The regulations according to VDE 0100 must be
observed!
For the use of the unit, an on-site fuse pro-
tection by means of (a) miniature circuit
breaker(s) is mandatory. No additional fuse
protection is required for the alarm relay if it
is connected to a low voltage of up to 30 V
maximum. Parameters for fuse protection
can be found in the technical data.