OJ UDG Series, Instructions Manual, Page: 1 / 8

1
INSTRUCTIONS
57004E 06/15 (JRK)
English
The thermostat is an electronic on/off ther-
mostat for temperature control of electric
underfloor heating by means of an NTC sensor
located either externally or internally within the
thermostat. The thermostat has a built-in two-
pole ground fault circuit interrupter (GFCI, Class
A). The thermostat and GFCI are suitable for
120-240 V (incl. 208 V) 50/60 Hz power sup-
plies.
The thermostat is for flush mounts in a wall
socket.
Product programme
Thermostats with built-in GFCI
UCG-4991 Programmable thermostat incl.
floor sensor
UDG-4999 Programmable thermostat with 2
sensors:
floor sensor and built-in room
sensor
UTN-4991 Non-programmable thermostat
incl. floor sensor
Power module with built-in GFCI
USG-4000 Power module without sensor
Mounting of floor sensor (fig. 3)
Floor sensor is supplied from SELV (Safety
Extra low Voltage) Circuit, allowing the sensor
to be placed as close to the floor surface as
desired without having to take special account
to the risk of shock at the damage to the sensor
cable. It is not intended that the temperature
sensor wire shall enter through the wall socket
mounting box. The sensor cable shall be sep-
erated from LINE and LOAD cables. Can be
separated in conduite, inside or outside the
wall. (see fig. 7)
Recommended placed in an non conductive
installation pipe, which is embedded in the
floor. (fig. 3). The pipe must be sealed in the end
and placed as high as possible in the concrete
layer. The sensor cable shall be placed in a sep-
arate pipe or be separated from power cables.
The floor sensor must be centered in between
the heating cable.
The sensor cable can be extended up to 90 ft
(30 m) by means of a separate two-core cable.
Two remaining cores of a multi-core cable
which, for example, supplies current to the floor
heating wires, must not be used. The two-core
cable must be placed in a separate pipe or be
separated from power cables.
Other approved floor sensors may be used if
they comply with the technical specifications
(see fig. 5).
Mounting of thermostat with built-in sensor
(UDG-4999) (fig. 4)
The room sensor is used for comfort tempera-
ture regulation in rooms. The thermostat should
be mounted on the wall approx. 5.4 ft (1.6 m)
above the floor in such a way as to allow free air
circulation around it. Draughts and direct sun-
light or other heat sources must be avoided.
Mounting of thermostat
Installation
TO AVOID ELECTRIC SHOCK, DIS-
CONNECT THE HEATING SYSTEM
POWER SUPPLY AT THE MAIN
PANEL BEFORE INSTALLING THE
THERMOSTAT.
KEEP THERMOSTAT AIR VENTS CLEAN AND
FREE FROM OBSTRUCTION.
This thermostat is an electrical product and
must be installed in compliance with the
National and/or Local Electrical Code. Instal-
lation must be performed by qualified person-
nel where required by law. The thermostat is
equipped with a ground fault circuit interrupter
(GFCI, Class A) which requires that the line
and load cables are isolated from one another
for correct operation. The thermostat is designed
for resistive load only. The resistive load must not
exceed 15 A (1800 W at 120 Vac / 3120 W at 208
Vac / 3600 W at 240 Vac).
During a ground fault, the two lines will be cut
off.
Line cable
Delivers power from the service panel (breaker
panel or fuse box) to the thermostat.
This cable must only be connected to the ther-
mostat’s line terminals, marked L1 and L2.
1. Connect power cable to terminals 2 and 3 on
the back of the thermostat (fig. 2).
Load cable
Delivers power from the thermostat to the heat-
ing cable.
This cable must only be connected to the ther-
mostat’s load terminals, marked load 15 A.
1. Connect heating cable to terminals 1 and 4
on the back of the thermostat (fig. 2).
The detachable cover on the back of the
thermostat (fig. 1) is designed to prevent unin-
sulated ground wires from dropping onto the
terminals after installation has been completed.
Warning
Do not loosen the terminal screws
further than the mechanical stop. Oth-
erwise this will damage the terminal
(fig. 2).
Temperature sensor
1. Use a screwdriver to release the catch and
remove the front cover (fig. 1).
2. Connect the floor sensor to the terminals
marked “sensor”, terminals C and D (fig. 6).
3. Mount the thermostat in the wall socket.
4. Carefully replace the front cover by first posi-
tioning its upper edge and then clicking it into
place.
Power module, type USG
If loads of more than 15 A are required, expan-
sion is possible using power modules.
Power modules can be connected to the live
cable and load cable, see relevant sections.
Maximum distance between thermostat and
power modules is 80 ft (25 m.)
Use field wiring cable, recommended min. 20
AWG. Connect A to C and B to D (fig. 6).
Operation
Types UCG and UDG (with built-in clock):
The first time the thermostat is connected,
time and day must be set. The thermostat will
automatically start up in the menu for setting
time and day.
Type UTN (without built-in clock):
The actual temperature setting is shown and the
thermostat is ready for use.
Checking the GFCI
It is important that the GFCI is checked for cor-
rect installation and function upon installation
and monthly thereafter.
To check the GFCI:
Press the “TEST” button.
The test is successful if the red LED on the
right of the thermostat flashes once every two
seconds and “GROUND FAULT” appears on
the display. If this does not occur, check the
installation.
Press the “Standby/Reset” button to reset the
GFCI.
The red LED will stop flashing and the display
returns to its normal appearance.
If the test fails, repeat the test. If it continues to
fail, ask an electrician to check the installation.
If, during normal operation, the GFCI trips
without the “TEST” button being pressed, there
could be a ground fault! To check whether it
is a ground fault or nuisance tripping, press
“Standby/Reset”. If this causes the red LED to
stop flashing and stay off, it was nuisance trip-
ping and the system is operating correctly. If
this does not occur, there is a ground fault! In
case of a ground fault, it is important to have
the installation checked by a qualified electri-
cian according to local and national regulations.
The red LED on the right of the thermostat can
indicate four different GFCI states:
1. LED off – NORMAL state.
2. LED flashing slowly (once every two seconds)
– TRIGGERED state. Try pressing the “Stand-
by/Reset” button to reset the GFCI.
3. LED flashing quickly (five flashes per second)
– ERROR state. Try switching the power off
and then back on again. If the thermostat
re-enters the ERROR state, either the wiring
is wrong (a GN exists) or the unit is defective
and must be replaced.
4. LED lit constantly – Internal microprocessor
malfunction or abnormal fault in hardware!
Try switching the thermostat off and then
back on again. If the LED is still constantly
lit, the GFCI is defective and the thermostat
must be replaced.
Note: The LED lights up briefly without flashing
during every power-up.
Programming
See user manual.
www.ojelectronics.com/UDG-download
Type UDG, UCG, UTN, USG
© 2015 OJ Electronics A/S