Raychem EMDR 10 Handbuch Seite 10

3.3 Moisture Sensor Fuse
The control unit is equipped with a fuse in the output for the moisture sensor which protects
this output against overload and short circuit. In case this fuse has to be replaced you may
exclusively use a fuse (5 x 20 mm) type T315mA according to IEC127-2/V.
Other fuse types are not permissible and may lead to serious damage of the unit.
4. FAuLT MESSAgES And TROuBLE SHOOTing
The following faults are being detected by the control unit:
Fault
Break or short circuit of the temperature sensor
Break of the moisture sensor
Short circuit of the moisture sensor
Power failure
Notice:
• A short circuit at the moisture sensor leads to the triggering of the fuse.
• By that a short circuit is being detected as well because it leads to a break of the
sensor circuit.
In case of a fault at the moisture sensor the moisture measuring circuit will be switched
off. The LED "moisture" will continue to flash. After repair of the moisture sensor the fault
signal has to be cleared by activating the TEST mode (turn the potentiometer for the lower
temperature limit to the left stop and shortly after that back again to the requested lower
temperature limit). When the air temperature falls below the value adjusted at the control
unit, then the moisture sensor is activated and tested again after approx. 10 minutes.
Trouble shooting:
Symptoms
Heating cable not heating Moisture sensor not positioned
(snow is not melting)
Temperature below set Moisture not detected
point, but heating cable
fails operate
Snow present,
but heating cable fails
to operate
10
Probable causes
correctly (e.g. not flat in the gutter) in the "Assembly of the Moisture
Temperature sensor located in
direct sunlight
Less than 10 minutes have elapsed The moisture sensor is not checked
since the temperature fell below the for the presence of moisture until
setpoint
below the setpoint
Moisture dial set too high
Poor positioning of the moisture Re-position following the instructions
sensor
Reaction
LED "temperature" flashes,
alarm relay and load relay switch off
LED "humidity" flashes,
alarm relay and load relay switch off
Additionally, under short circuit conditions,
Moisture sensor fuse will rupture.
Alarm relay and load relay switch off
Correction
Re-position following the instructions
Sensor" section of this manual
Re-position following the
instructions in the "Assembly of
the Temperature Sensor" section of
this manual
This is normal operation: low temper-
ature AND moisture must be to
detected before the heating cable
is energized
10 minutes after the temperature falls
Set the moisture dial to a lower
value
in the "Assembly of the Moisture
Sensor" section of this manual