BN Thermic OUH3 Series User manual

Thank you for purchasing a BN Thermic product. Manufactured to a high standard, this product will, if used according to these
instructions and properly maintained, give you years of trouble-free performance.
To make sure that you have selected the correct heater for your application, please read Section 13 on the back page before
installation.
1. SAFETY INSTRUCTIONS
1.1 ELECTRICAL SAFETY
WARNING! It is the responsibility of the owner and the operator to read, understand and comply with the following:
You must check all electrical products, before use, to ensure that they are safe. You must inspect power cables, sockets and any other
connectors for wear or damage. You must ensure that the risk of electric shock is minimised by the installation of appropriate safety devices.
If in any doubt consult a qualified electrician.
You must also read and understand the following instructions concerning electrical safety.
The Health & Safety at Work Act 1974 makes owners of electrical appliances responsible for the safe condition of those appliances and the
safety of the appliance operators. If in any doubt about electrical safety, contact a qualified electrician.
Installation should in accordance with current IEE electrical regulations.
Ensure that the insulation of all the cables on the appliance are undamaged and safe, before connecting it to the power supply.
Ensure that the cables are always protected against short circuit and overload.
Regularly inspect the power supply cables and plugs etc. for wear or damage and check all connections to ensure that none are loose. This
is especially important on the internal mains connecting terminal block as any vibration may loosen the terminal screws.
Important: Ensure that the voltage marked on the appliance matches the power supply to be used and that a correctly rated fuse is fitted.
DO NOT use worn or damaged cables, plugs or connectors. Immediately have any faulty item repaired or replaced by a qualified electrician.
A suitable local isolating switch must be provided in the electrical supply circuit as close as possible to the heater with at least 3mm clearance
on each pole. This must only be used to turn off the heater in an emergency or once the heater has fully cooled down.
This heater is IP20 rated and is suitable for indoor use only.
The controls and heaters may be fed from a different source, and it is essential that all circuit breakers feeding the heating system are isolated
prior to any work being carried out on any of the heaters in the system.
If there are 2 or more heaters being used as a Master / Slave system there may be 400v ac present in the control boxes due to supplies being
taken from different phases.
If you connect the heaters together in a Master / Slave configuration you can only use one RCD (Residual Circuit Device) for all heaters and
individual MCB’s for each heater.
Do not attach this heater to an extension cord it must be hard wired in position.
1.2 GENERAL SAFETY INSTRUCTIONS
Remove all packaging and store it away from children, check the package and
heater for visible damage or tampering.
Familiarise yourself with the applications and limitations of the heater.
Ensure the heater is in good order and condition both physically and electrically
before use. If in any doubt, do not use the unit and contact your supplier.
Only use recommended attachments and parts. To use unauthorised parts
may be dangerous and will invalidate your warranty.
Keep tools and other items away from the heater when it is in use.
Keep children and unauthorised persons away from the heater, as it gets hot.
Disconnect from mains and allow to cool before attempting any cleaning or
maintenance.
XDO NOT use in areas where hazardous gases or dusts may be present.
XDO NOT locate the heater directly below the power outlet.
XDO NOT disassemble the heater for any reason. This heater must be checked
by qualified personnel only.
XDO NOT use this heater to perform a task for which it has not been designed.
 WARNING! Ensure you observe the safety distances and mounting heights
and there is no possibility of inflammable materials coming into contact.
INSTRUCTIONS FOR:-
INDUSTRIAL SPACE HEATER
OUH3 Series
REGISTER: PLEASE REGISTER THIS PRODUCT ONLINE TO ACTIVATE YOUR GUARANTEE AT
www.bnthermic.co.uk
IMPORTANT: PLEASE READ THESE INSTRUCTIONS, NOTE THE SAFE OPERATIONAL REQUIREMENTS, WARNINGS, AND CAUTIONS.
USE THIS PRODUCT CORRECTLY, AND WITH CARE FOR THE PURPOSE FOR WHICH IT IS INTENDED. FAILURE TO DO SO MAY CAUSE
DAMAGE AND/OR PERSONAL INJURY AND WILL INVALIDATE THE WARRANTY.

2. INTRODUCTION & SPECIFICATION
This heater produces a totally dry heat, no condensation, no gas, no fumes. It reaches maximum heat output within a few minutes of
being turned on. It is quick and easy to install reducing installation costs. Air temperature can be controlled by the heater’s built-in
thermostat or alternatively by a variety of remote-mounted thermostats and other control devices. Where required, a group of heaters
can be interconnected and controlled from a single remote-mounted thermostat. This allows a very easy and cheap way of controlling
heating in large or small areas.
3. MOUNTING INSTALLATION
The heater is supplied with a multi-functional mounting bracket.
If required, as an optional extra the heater can be hung using 4 x M8 ring hooks. Order code – OUH3-HK.
LOCATION - For best results, do not mount higher than 2.4m (small models) and 2.8m (large Models). If you need to exceed this
height either mount on the multi-functional bracket so the heater is at an angle facing downwards or use hanging hooks (optional
extra). Direct air flow away from occupants, posts, and columns, including equipment. Ideally allow the warm air to travel parallel to
the outside walls, along the most exposed part of the building, which is normally subjected to the prevailing winds (see pictures below).
MULTI-FUNCTIONAL BRACKET - Using the pictures above and to the right, decide on the best mounting method to suit your
requirements. Fix the bracket to the wall or roof making sure you use suitable bolts for the surface you are fixing the bracket to and
ensure it will take the weight of the heater. Insert the heater’s stud through the bracket, add the washer and secure in place using the
nylock nut supplied.
HANGING EYE HOOKS (Optional extra code – OUH3-HK) – Place the nut onto each eye hook first then fully screw them into the
heater, finally tighten the nuts against the heater body to stop them rotating.
Model
Power
Input Supply
Single
phase
wiring
Amps
Three Phase
wiring
Amps / per
Phase
Dimensions
W x D x H (mm)
Weight
Recommended
Mounting
Height
Safety Distance
from Heater
OUH3-03
3kW
230V ac
13A
----
435 x 405 x 320
18kg
2.4m
2.0m
OUH3-06
6kW
230V ac
26.1A
----
435 x 405 x 320
18kg
2.4m
2.0m
OUH3-09
9kW
230v ac or 400v 3Ph+N
39.2A
13.1A / Ph
435 x 405 x 320
18.5kg
2.4m
2.0m
OUH3-15
15kW
400v 3Ph+N
------
21.75A / Ph
565 x 485 x 445
37kg
2.8m
2.0m
OUH3-20
20kW
400v 3Ph+N
------
29A / Ph
565 x 485 x 445
37.5kg
2.8m
2.0m
OUH3-25
25kW
400v 3Ph+N
------
36.25A / Ph
565 x 485 x 445
38.5kg
2.8m
2.0m
2
Single heater location
Multi heater locations

If you use the heater in mounting position 7, 8 or 9 you MUST
remove the 2 side panels turn them around 180° and reinstall them.
Would you also please turn around the front guard so our Logo
reads correctly. Many Thanks
3
1
3
4
5
6
2
7
8
9

4. ELECTRICAL CONNECTIONS
The 3KW, 6kW can only be wired 230V single phase.
The 9kW can be wired 230V single phase or 400V 3 phase.
The 15kW, 20kW and 25 kW can only be wired 400V 3 phase.
All Heaters MUST BE EARTHED.
Due to the heater having “Fan Over Run” circuitry the heater must not be turned ON and OFF using the mains supply
isolator. The mains supply isolator should only be used in an emergency or if you need to turn off the heater (once cooled
down) for long periods. The heater should be turned off using the thermostat on the back or any approved control device.
See Section 8 for further information on the fan over run.
On 3kW, 6kW and 9kW units there are 4 x 20mm and 1 x 25mm knockouts on the top and bottom of the heater and an additional 4 x 20mm and 1 x
25mm knockouts on the back of the heater. If you require a 32mm hole, gently open out a 25mm hole using a taper drill or step drill. Be careful you
do not touch the internal electrics when opening up the holes.
On 15kW, 20kW and 25kW units there are 3 x 20mm, 1 x 25mm and 1 x 32mm knockouts on the top or bottom of the heater and an additional 3 x
20mm, 1 x 25mm and 1 x 32mm knockouts on the back of the heater.
4.1 OUH3-03 230V Single Phase (only suitable for 3kW model)
Please make sure you have read the Safety instructions and that you are a suitably qualified electrician before continuing.
Please Note:- Specified cable sizes are for typical installations, correction factors may need to be used when determining actual cable sizes.
Do NOT use power tools to undo or do up terminal screws.
Cable Size
Use minimum 1.5mm² 3 Core Mains Cable (see note above).
Connect Brown / Live Wire – Terminal L1 of Heater
Connect Blue / Neutral Wire – Terminal N of Heater
Connect Green/ Yellow / Earth Wire – Terminal E of Heater
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS
INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
4.2 OUH3-06 230V Single Phase (only suitable for 6kW model)
Please make sure you have read the Safety instructions and that you are a suitably qualified electrician before continuing.
Please Note:- Specified cable sizes are for typical installations, correction factors may need to be used when determining actual cable sizes.
Do NOT use power tools to undo or do up terminal screws.
The Link Plate should already be present in the terminal block. Do Not remove it.
Cable Size
Use minimum 4mm² 3 Core Mains Cable (see note above).
Connect Brown / Live Wire – Terminal L1 of Heater
Connect Blue / Neutral Wire – Terminal N of Heater
Connect Green/ Yellow / Earth Wire – Terminal E of Heater
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS
INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
4

4.3 OUH3-09 230V Single Phase (only suitable for 9kW model)
Please make sure you have read the Safety instructions and that you are a suitably qualified electrician before continuing.
Please Note:- Specified cable sizes are for typical installations, correction factors may need to be used when determining actual cable sizes.
Do NOT use power tools to undo or do up terminal screws.
The 2 Link Plates are attached to these instructions. They link between terminals L1 & L2 + L2 & L3. Please ensure you tighten up the screws
firmly holding them in position.
Cable Size
Use minimum 6mm² 3 Core Mains Cable (see note above).
Connect Brown / Live Wire – Terminal L1 of Heater
Connect Blue / Neutral Wire – Terminal N of Heater
Connect Green/ Yellow / Earth Wire – Terminal E of Heater
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS
INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
4.4 400V 3 PHASE – for OUH3-09 (only use when wiring 9kW model 400V 3 phase)
Please make sure you have read the Safety instructions and that you are a suitably qualified electrician before continuing.
Please Note:- Specified cable sizes are for typical installations, correction factors may need to be used when determining actual cable sizes.
Do NOT use power tools to undo or do up terminal screws.
DO NOT USE the Link Plates attached to these instructions.
Cable Size
Use 1.5mm² 5 Core Mains Cable (see note above).
Connect Brown / Phase 1 Wire – Terminal L1 of Heater
Connect Black / Phase 2 Wire – Terminal L2 of Heater
Connect Grey / Phase 3 Wire – Terminal L3 of Heater
Connect Blue / Neutral Wire – Terminal N of Heater
Connect Green/ Yellow / Earth Wire – Terminal E of Heater
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON
AS INCORRECT WIRING IS NOT COVERED BY THE
GUARANTEE
4.5 400V 3 PHASE – for OUH3-15, 20 & 25
Please make sure you have read the Safety instructions and that you are a suitably qualified electrician before continuing.
Please Note:- Specified cable sizes are for typical installations, correction factors may need to be used when determining actual cable sizes.
Do NOT use power tools to undo or do up terminal screws.
Cable Sizes
OUH3-15 15kW - Use 4mm² 5 Core Mains Cable (see note above).
OUH3-20 20kW - Use 4mm² 5 Core Mains Cable (see note above).
OUH3-25 25kW - Use 6mm² 5 Core Mains Cable (see note above).
Connect Brown / Phase 1 Wire – Terminal L1 of Heater
Connect Black / Phase 2 Wire – Terminal L2 of Heater
Connect Grey / Phase 3 Wire – Terminal L3 of Heater
Connect Blue / Neutral Wire – Terminal N of Heater
Connect Green/ Yellow / Earth Wire – Terminal E of Heater
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT
WIRING IS NOT COVERED BY THE GUARANTEE
5
Link
Plates

If you are not using any controls other than the heater’s built-in thermostat AND are not using the heater in a
Master/Slave configuration go to section 7 – LINK CONNECTIONS (page 11).
5. ADDING ADDITIONAL CONTROLS.
You may add the following controls to the OUH3 Space Heater all of these controls if connected as shown in the wiring diagrams
are protected by the heaters internal 3A fuse.
•OUH3-S Heater control switch – Remote way of turning the heater ON/OFF or selecting Fan Only
in the summer. We recommend this as a minimum control for your heater. This can either be wall
mounted or fixed to the back of the heater using knockout and screw holes provided.
•OUH3-DT Digital Thermostat - A 7 Day, 6/1 Day or 5/2 Day programmable thermostat which offers four time and temperature
changes each day. There is also a switch for selecting Fan Only / Off / Heat (if thermostat allows). You may also install a remote
sensor if you wish to install the thermostat in a different location or area to the heaters. All settings are stored in the controller with
battery back-up.
•OUH3-WiFi Wi-Fi version of the OUH3-DT thermostat which can be controlled on a mobile phone. There is also a switch for
selecting Fan Only / Off / Heat (if thermostat allows). You can also use a remote sensor if you wish to allow the thermostat to be
installed in a different location to the heaters. All settings are stored in the controller with battery back-up.
•PROTIM-7 7 Day programmable timer. This timer will only allow the heating to operate during the “ON” time settings. During
“OFF” period there is a “Boost” button that with one press allows heating to operate for 1 hour or with 2 presses 2 hours
before turning off. The boost can be cancelled by pressing the “Boost” button a third time.
•PROSTAT4 The PROSTAT4 thermostat is a highly accurate electronic temperature controller suitable for heavy duty use
in public areas. There are two temperature settings switchable through a push button and integral countdown timer. Optional
remote sensors are available if temperature control is required away from the controller.
•RST-RS Rough service, tamper resistant thermostat – Can be used on its own as a room thermostat or in conjunction with the
OUH3-S Heater control switch.
•FST-RS Rough Service, tamper resistant frost thermostat –This thermostat overrides all other controls including the OUH3-S,
OUH3-DT or OUH3-Wi=IFI when they are set to OFF. This is used to protect the heated area against low temperatures that
may cause damage or freezing of water etc. The thermostat MUST be mounted out of direct air flow of the heater.
•PROSTAT2 Battery Operated Digital Thermostat is a 7 Day or 5/2 Day programmable room thermostat which offers six time
and temperature changes each day. All settings are stored in the controller.
•RST3-IN thermostat – Can be used on its own as a room thermostat or in conjunction with the OUH3-S Heater control switch.
•CXS Remote Temperature Sensor – Used with OUH3-DT and OUH3-WiFi to read temperature in a different area to the controller.
If you connect heaters in a Master / Slave configuration (See Section 6) controls are only added to the master heater and all
the slave heater(s) will follow the master.
OUH3-S
Heater Control Switch
RST-RS / FST-RS
Tamper Resistant thermostats
PROTIM-7
7 Day Time Switch
RST3-IN
Thermostat
6
PROSTAT4
2 Set Point Thermostat
PROSTAT2
Battery Digital Thermostat
OUH3-DT
Digital Thermostat
+ Fan Only
Switch
OUH3-WiFi
WiFi Thermostat + Fan Only Switch
CXS
Remote Sensor

5.1 CONECTING A OUH3- S HEATER CONTROL SWITCH
This can either be mounted on a wall or on the back of the heater next to the thermostat. If mounting on the heater, remove the knockout in the heater
and electrical box of the OUH3-S and screw onto the heater using 2 x M4 screws and nuts (not supplied).
Use 0.75mm² 4 core cable
Connections – (Colours for reference only)
Connect Brown Live wire – Terminal 3 of Heater and Terminal L on Control Switch (230V Live connection).
Connect Grey Live wire – Terminal 4 of Heater and Terminal 1 on Control Switch.
Connect Black wire – Terminal 5 of Heater and Terminal 2 on Control Switch.
Connect Green / Yellow wire – Terminal E or of Heater and Terminal E (Earth connection) on Control Switch.
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
5.2 CONECTING A RST-RS or RST3 -IN THERMOSTAT & OUH3 - S CONTROL SWITCH
HEATER to CONTROL SWITCH
Use 0.75mm² 3 or 4 core cable
Connections – (Colours for reference only)
Connect Brown Live wire – Terminal 3 of Heater and Terminal L on Control Switch (230V Live connection).
Connect Grey Live wire – Terminal 4 of Heater and Terminal 1 on Control Switch.
Connect Green / Yellow wire – Terminal E or of Heater and Terminal E (Earth connection) on Control Switch.
HEATER to THERMOSTAT
Use 0.75mm² single core wire OR add it to multi core cables
Connect Black wire – Terminal 5 of Heater and Terminal Lout on RST-RS Thermostat or Terminal 3 on RST3-IN Thermostat. Please note; Black wire
can be joined in the control switch using a suitable terminal block to allow easy install of controls. Black wire carries 230v.when thermostat is on.
CONTROL SWITCH to THERMOSTAT
Use 0.75mm² 2 or 3 core cable
Connections – (Colours for reference only)
Connect Red wire – Terminal 2 of Control Switch and Terminal Lin on RST-RS Thermostat or Terminal 1 on RST3-IN Thermostat.
Connect Green / Yellow wire – Terminal E or of Control Switch and Terminal E (Earth connection) on Thermostat.
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
PLEASE NOTE:-Turn up fully the internal thermostat on the back of the heater so it does not override this thermostat.
The controls and heaters may be fed from a different source and it is essential that
all circuit breakers feeding the heating system are isolated prior to any work being
carried out on any of the heaters in the system.
OUH3-S Mounted on the
back of the heater
Links may be
required
– S
ee
Section 7
Links may be
required
– S
ee
Section 7
The controls and heaters may be fed from a different
source and it is essential that all circuit breakers feeding
the heating system are isolated prior to any work being
carried out on any of the heaters in the system.
7

5.3CONECTING A OUH3-DT OR A OUH3-WiFi THERMOSTAT + FAN ONLY OPTION
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
5.4CONECTING A FST- RS FROST PROTECTION THERMOSTAT
5.5CONECTING A PROTIM-7 7 DAY PROGRAMABLE TIMER
Use 0.75mm² 4 core cable
Connections – (Colours for reference only)
Connect Brown Live wire – Terminal 1 of Heater and Terminal L on
Programmable Timer (230V Live connection).
Add a Link cable (1mm²) between Timer L connection and Timer Sin
connection.
Connect Black wire – Terminal 2 of Heater and Terminal Sout on
Programmable Timer.
Connect Blue Neutral wire – Terminal N of Heater and Terminal N on Programmable Timer (230V Neutral connection).
Connect Green / Yellow wire – Terminal E or of Heater and Terminal E (Earth connection) on Programmable Timer.
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
8
The controls and heaters may be fed from a different source and it is essential that all circuit breakers feeding the heating system are isolated prior
to any work being carried out on any of the heaters in the system.
Use
0.75mm² 5 core cable
Connections
– (Colours for reference only)
Connect Brown Live wire
– Terminal 1 of Heater and Terminal “Lin” on Control Switch.
Connect Grey Live wire
– Terminal 4 of Heater and Terminal “Fan” on Control Switch.
Connect Black wire
– Terminal 5 of Heater and Terminal “Heat” on Control Switch.
Connect Bl
ue wire – Terminal N of Heater and Terminal N on Control Switch.
Connect Green / Yellow wire
– Terminal E or of Heater and Terminal E on Control
Switch
Links may be
required
– S
ee
Section 7
The controls and heaters may be fed from a different source and it is essential that all circuit breakers feeding the heating system are isolated
prior to any work being carried out on any of the heaters in the system.
Use 1.0mm² 3 core cable
Connections
– (Colours for reference only)
Connect Black wire
– Terminal 10 of Heater and Lout on Frost Thermostat.
Connect Brown Live wire
– Terminal 11 of Heater and Lin on Frost Thermostat (230V Live
connection).
Connect Green / Yellow wire
– Terminal E or of the Heater
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING
IS NOT COVERED BY THE GUARANTEE
.
Links may be required
– See Section 7
The controls and heaters may be fed from a different source and it is essential that all circuit breakers feeding the heating system are isolated
prior to any work being carried out on any of the heaters in the system.
NO additional
Links are required.

5.6 CONECTING A RST3- IN or RST-RS THERMOSTAT
Use 1.0mm² 3 core cable
Connections – (Colours for reference only)
Connect Red wire – Terminal 3 of Heater and Terminal 1 on an RST3-IN Thermostat or Terminal Lin on an RST-RS Thermostat.
Connect Black wire – Terminal 5 of Heater and Terminal 3 on an RST3-IN Thermostat or Terminal Lout on an RST-RS Thermostat.
Connect Green / Yellow wire – Terminal E or of Heater and Terminal E (Earth connection) on either Thermostat.
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
PLEASE NOTE:-Turn up fully the internal thermostat on the back of the heater so it does not override this thermostat
5.7 CONECTING A PROSTAT4 THERMOSTAT
Use 0,75mm² 4 core cable
Connections – (Colours for reference only)
Connect Red wire – Terminal 3 of Heater and Power IN - Live Terminal (L) on Thermostat.
Connect Black wire – Terminal 5 of Heater and Heaters Live Terminal (L) on Thermostat. Black wire carries 230v when thermostat is on.
Connect Blue Neutral wire – Terminal N of Heater and Power IN - Neutral Terminal (N) on Thermostat.
Connect Green / Yellow wire – Terminal E or of Heater and Terminal E (Earth connection) on Thermostat.
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
PLEASE NOTE:-Turn up fully the internal thermostat on the back of the heater so it does not override this thermostat
5.8CONECTING A PROSTAT2 THERMOSTAT
Use 1.0mm² 3 core cable
Connections – (Colours for reference only)
Connect Brown Live wire – Terminal 1 of Heater and Terminal 2 on the Thermostat (230V
Live connection).
Connect Grey Live wire – Terminal 2 of Heater and Terminal 3 on the Thermostat.
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
PLEASE NOTE:-Turn up fully the internal thermostat on the back of the heater so it does not override this thermostat.
The controls and heaters may be fed from a different source and it is
essential that all circuit breakers feeding the heating system are isolated
prior to any work being carried out on any of the heaters in the system.
Links may be
required
– S
ee
Section 7
The controls and heaters may be fed from a different source and it is
essential that all circuit breakers feeding the heating system are isolated
prior to any work being carried out on any of the heaters in the system.
Links may be
required
– S
ee
Section 7
9
Links may be
required
– S
ee
Section 7

6. CONECTING HEATERS IN A MASTER SLAVE ARANGEMENT
IF USING THE HEATERS IN A MASTER / SLAVE ARANGEMENT PLEASE READ THE FOLLOWING IMPORTANT NOTES
BEFORE STARTING THE INSTALATION.
All OUH3 heaters may be connected in a Master / Slave arrangement.
The OUH3 heaters do not need to be the same Wattage or size.
Some OUH3 can be connected using 400v 3 phase supply and some Single phase and still linked as Master / Slaves.
If Using RCD (Residual Circuit Device) all Heaters connected in a Master / Slave arrangement MUST be supplied from the same
RCD and not multiple RCD’s. Then use a MCB for each heater.
The controls are always added to the master heater and NEVER to any of the slave heaters. You may designate any OUH3 heater
to be the master as long as you adhere to the following.
1) Controls are only added to the master unit.
2) Controls if connected as shown in the wiring diagrams on pages 7 – 9 are protected by the master heaters internal 3A fuse.
3) Link connections / cables (see section 7), if required are only added to the master unit.
4) You are fully aware that if a slave unit is present in the system 400v ac may be present in the terminal blocks even if all heaters
are run on single phase. This is because the supply to each heater may be taken from a different phase.
5) A maximum of 1 master and 15 slaves are used in each configuration.
6) Older OUH2 model heaters can still be connected to these new OUH3 models.
Connect the mains wire to each heater as per section 4.
Decide which heater is going to be the master heater and connect the controls to it as per section 5.
Link the master to the first slave as per drawing below and instructions on next page.
Link first slave to second slave as per drawing below and instructions on next page.
Linking Heater in a Master / Slave Configuration
The controls and heaters may be fed from
a different source and it is essential that
all circuit breakers feeding the heating
system are isolated prior to any work
being carried out on any of the heaters in
the system.
10

Do NOT use power tools to undo or do up the terminal screws.
Linking Master Heater to First Slave Heater - Use 1.0mm² 3 core cable
Connections – (Colours for reference only)
Connect Black wire – Terminal 6 of Master heater and Terminal 6 of first Slave heater.
Connect Grey wire – Terminal 7 of Master heater and Terminal 7 of first Slave heater.
Connect Green / Yellow wire – Terminal E or of Master heater and Terminal E or of first Slave heater.
Linking Further Slave Heaters - Use 1.0mm² 3 core cable
Daisy chain slave heaters as per drawing to the left (Maximum number of slave heaters is 15)
PLEASE CHECK ALL CONNECTIONS BEFORE TURNING ON AS INCORRECT WIRING IS NOT COVERED BY THE GUARANTEE
7. LINK CONNECTIONS
LINK CABLES ARE ONLY NEEDED IN SINGLE HEATERS USED ON THEIR OWN OR IN A MASTER HEATER AND DEPEND UPON WHICH
CONTROLS YOU USE
NEVER ADD ANY LINKS TO SLAVE HEATERS- THIS COULD DAMAGE YOUR HEATERS AND IS NOT COVERED BY THE GUARANTEE
SINGLE HEATERS or MASTER HEATER LINKS
If you are NOT fitting a PROTIM-7 Timer or a PROSTAT2 Thermostat or OUH3-DT Digital
Thermostat or OUH3-WiFi Thermostat to a single heater or the master heater in a Master /
Slave set up LINK Terminals 1 & 2 (use 1.0mm² wire) as shown in drawing to the right.
DO NOT PUT THIS LINK CABLE IN ANY OF THE SLAVE HEATERS
If you are NOT fitting an OUH3-S Heater Control Switch or OUH3-DT Digital Thermostat or
OUH3-WiFi Thermostat or RST-RS or RST3-IN Thermostats or a PROSTAT4 Thermostat
to a single heater or the master heater in a Master / Slave set up LINK Terminals 3 & 5 (use
1.0mm² wire) as shown in drawing to the right. DO NOT PUT THIS LINK CABLE IN ANY
OF THE SLAVE HEATERS
8. BMS CONNECTION
You can connect the heaters to a building management system (BMS). If your BMS can switch 230V no other parts are required. If your BMS works
on low voltage e.g 12v DC you will need to add a suitable relay into the system. There are two options for connecting into you BMS: Fan Only + Heat
Only or Heat Only. Use the correct drawing below to connect the heaters. The Brown wire is the feed from the Master Heater. This is a 3A 230v live
output. The return wires (Grey for Fan Only and Black for Heat) must also be capable of carrying 230v 3A. If the Heaters are connected in a Master /
Slave set up just connect the BMS to the Master heater and all the slaves connected will follow. The thermostat on the back of each heater still works.
9. FAN OVER RUN
The heater incorporates a fan over run device that ensures that when the elements turn off, the temperature of the heater case and internal components
does not increase significantly. This may either work by allowing the fan to continue running for a while when the elements turn off or by turning the fan
back on if the temperature rises when the heater elements and fan turn off. This will normally only occur for a couple of minutes after the heating
elements turn off. It is for the above reason that you must turn off the heater using a control device, BMS or the internal thermostat and NOT by isolating
the mains power. Continuous turning ON and OFF of the heater using the mains supply isolator whilst it is running, can damage the heater and is not
covered by the guarantee.
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10. TROUBLE SHOOTING AND SOLUTIONS
Wall thermostat does not work correctly in a Master / Slave set up or single heater.
Check that you have turned up fully the inbuilt thermostat on the back of the heater as this will turn off the heater if set to a lower temperature than
the wall thermostat.
Single heater won’t turn on from new.
Check that you have fitted any required links – See section 7.
I have a OUH3-S heater control switch it is set to “OFF” but the heaters are still coming on.
This will happen if you have a Frost Thermostat fitted as it overrides everything to help protect your building from damage by cool temperatures.
Can I add different controllers or additional heaters at a later date?
Yes you can add additional controllers or additional OUH3 heaters at a later date. Contact you electrician or electrical wholesale for further information.
Why does one heater turn on using a Master / Slave set up but the others stay off?
If you are using the internal thermostat in the heaters this is perfectly normal and one of the new advance features. Each heater turns on / off on its
own thermostat so that if one heater was mounted near an outside door or in a cooler part of the building it would turn on more often. The remaining
heaters in the warmer areas would stay off. The OUH3-S heater control switch overrides all internal thermostats and turns off every heater.
I need help!
If you have read these instructions and still need help please call us on the number on the back page during office hours and our technical department
will assist you. Please have these instructions in front of you when calling as this will assist us in helping you.
11 . MAINTENANCE
Note: Before examining or carrying out any maintenance, ensure the heater has cooled down and is disconnected from the mains supply. Due to the
design of this heater, there may be two different feeds if so ensure both are disconnected from the mains supply.
The heaters are intended to operate for many years, problem-free. All moving parts are factory lubricated and therefore should require no service.
Maintenance is limited to keeping both the inlet and outlet areas free from any accumulation of dust or any other foreign materials. This is especially
important immediately before the heating season. Any dust build up can be loosened using a brush and a vacuum cleaner applied to the airways to
ensure completed removal of any dust. A regular visual inspection of the heating elements is also recommended. When the heater is first turned on
after cleaning an unusual odour may be noted. This is due to the dust particles which inevitably will be disturbed and will be burnt off from the heating
element. If in any doubt always consult a qualified electrician for advice.
12 . MANUAL RESET CUT OUT
The following should only be carried out by a qualified electrician.
This heater is fitted with a manual resettable safety device to prevent
overheating. The device is located inside the electrical control box
and will stop the contactor from working until it is reset. The contactor
turns the heating elements on and off. Under normal conditions and
operation this cut-out should never operate. Should the cut-out
operate, disconnect the heater from the mains supply. Be aware that
the heater may be fed from two different supplies. Wait for a minimum
of 5 minutes to allow the heater to cool down, check and remove any
foreign materials around the airways. Now reset the cut-out by
pressing the black knob on the top. If the problem persists, please
contact us.
13. IMPORTANT NOTES REGARDING SPACE HEATING – PLEASE READ BEFORE INSTALLING
Total output
It is vital that the combined output of the heaters exceeds the heat losses from the entire area you are heating. If you are in any doubt, please contact
BN Thermic and we can carry out a quick check for you.
Temperature rise
OUH3 industrial fan heaters warm a space by circulating large volumes of air. The temperature rise across the heater is often barely detectable. This
is normal for this style of heater and does not indicate a fault. Our customer service advisers would be happy to talk through this characteristic of
industrial fan heaters if clarification is needed.
Now you have read and accepted the above points, please continue with your installation by reading through the instructions first. Any
questions you may have call our customer service advisors who will be delighted to help you.
NOTE: It is our policy to continually improve products and as such we reserve the right to alter data, specifications and component parts without prior
notice.
IMPORTANT: No liability is accepted for incorrect use of this product.
WARRANTY: Your BN Thermic product is guaranteed for a period of five years from date of purchase
assuming standard comfort heating application. Our warranty does not cover corrosion or incorrect
installation. We will repair or replace at our discretion any part found to be defective. We cannot assume
any consequential liability. This guarantee in no way prejudices your rights under common law and is
offered as an addition to consumer liability rights.
REGISTER: Activate your warranty by registering online at www.bnthermic.co.uk and retain this
installation data for future reference. OUH3INS-v01
WEEE REGULATIONS:
This appliance bears the symbol of the crossed waste bin. This indicates that, at the end of its useful life, it must not be disposed of as domestic
waste, but must be taken to a collection centre for waste electrical and electronic equipment. It is the user's responsibility to dispose of this
appliance through the appropriate channels. Failure to do so may incur penalties established by laws governing waste disposal.
BN Thermic Ltd,
34 Stephenson Way, Crawley,
RH10 1TN
Tel: [phone]
[e-mail]
www.bnthermic.co.uk
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