Ambirad VISION VT Series User manual

Doc No. 700025 Page of 32
INDEX Section
Introduction and Document Index
Installation Requirements --------------------------------------------------1
Assembly Instructions -------------------------------------------------------2
Commissioning Instructions -----------------------------------------------3
Servicing Instructions--------------------------------------------------------4
Spare Parts --------------------------------------------------------------------5
Fault Finding Guide----------------------------------------------------------6
Replacing Parts ---------------------------------------------------------------7
User and Operating Instructions ------------------------------------------8
AAMBIMBIRRADAD VVISIONISION®VT RVT RANGEANGE
RRADIANTADIANT TTUBEUBE HHEATERSEATERS
IINSTALLATIONNSTALLATION ANDAND OOPERATINGPERATING MMANUALANUAL
Part No. 700025
Nortek Global HVAC (UK) Limited, Fens Pool Avenue, Brierley Hill, West Midlands, DY5 1QA
WARNINGS
Nortek Global HVAC (UK) Ltd equipment must be installed and maintained in accordance with
the relevant provisions of the Gas Safety (Installations and Use) Regulations 1998 for gas fired
products. Due account should also be taken of any obligations arising from the Health and Safe-
ty at Works Act 1974 or relevant codes of practice. In addition the installation must be carried
out in accordance with the current IEE wiring regulations (BS 7671), BS 6896 (Industrial & Com-
mercial) and any other relevant British Standards and Codes of Practice by a qualified installer.
All external wiring MUST comply with the current IEE wiring regulations.

Doc No. 700025 Page 2 of 32
Introduction.
Document Index.
1 Installation Requirements
1.1 Health & Safety
1.2 Model Definitions
1.3 Heater Suspension
1.4 Wall Mounting
1.5 Clearance to Combustibles
1.6 Gas Connection & Supply Details
1.7 Electrical Connections
1.8 Ventilation Requirements
1.8.1 Unflued Radiant Heater
Mechanical Ventilation
Natural Ventilation
1.8.2 Flued Radiant Heater
Mechanical Ventilation
Natural Ventilation
1.9 Flue & Combustion Air Inlet Options
1.10 Technical Details
2 Assembly Instructions
2.1 Tools Required
2.2 Assembly Notes
2.2.1 Tubes
2.2.2 Turbulators
2.2.3 Brackets
2.2.4 Couplers
2.2.5 U Bends
2.2.6 Reflectors
2.2.7 End Caps
2.2.8 Burner Assembly
2.2.9 Flue Outlet
2.2.10 Detailed Assembly Drawings
3 Commissioning Instructions
3.1 Tools Required
3.2 Commissioning Chart for VT Heaters
4 Servicing Instructions
4.1 Tools Required
4.2 Burner Description
4.3 Burner Removal
4.4 Burner Gas Injector Servicing
4.5 Combustion Fan Servicing
4.6 Burner Head and Electrode Servicing
4.7 Radiant Tube Servicing
4.8 Reflector Servicing
4.9 Inspection of Flue
4.10 Re-commissioning after Service
5 Spare Parts
6 Fault Finding Guide
7 Replacing Parts
7.1 Burner Controller Replacement
7.2 Air Pressure Switch Replacement
7.3 Gas Valve Replacement
8 User and Operating Instructions
8.1 To Start Heater
8.2 To Switch Off Heater
8.3 Routine Maintenance Between Service Intervals
8.4 Frequency of Servicing
and attention is required to ensure that working
at height regulations are adhered to at the
mounting heights specified.
PLEASE READ this document prior to
installation to familiarise yourself with the
components and tools you require at the various
stages of assembly.
All Dimensions shown are in mm unless
otherwise stated.
The manufacturer reserves the right to alter
specifications without prior notice.
Welcome to the new range of high efficiency
AmbiRad Vision Hi/Low radiant tube heaters.
Local regulations may vary in the country of use
and it is the installers responsibility to ensure
that such regulations are satisfied.
All installation, assembly, commissioning and
service procedures must be carried out by
suitable qualified competent persons to the
statutory regulations in the country of use.
When assembling, installing, commissioning
and servicing is undertaken on radiant tube
heaters specified in these instructions, due care

Doc No. 700025 Page 3 of 32
1.1 Health and Safety
AmbiRad heaters must be installed in
accordance with the relevant provisions of the
Gas Safety (Installations and Use) Regulations
1998. Due account should also be taken of any
obligations arising from the Health and Safety
at Works Act 1974 or relevant codes of
practice. In addition the installation must be
carried out in accordance with the current IEE
wiring regulations (BS 7671), BS 6896:2005
(Industrial & Commercial) and any other
relevant British Standards and Codes of
Practice by a qualified installer. Isolate all
electrical supplies to the heater & controller
before proceeding.
For your own safety we recommend the use of
safety boots and leather faced gloves when
handling sharp or heavy items. The use of
protective eye wear is also recommended.
1.2 Model Definitions
VTUT = AmbiRad Vision U Tube heater with
painted forced two stage burner, stainless steel
reflector & end caps.
VTLF = AmbiRad Vision Single Linear heater
with painted forced two stage burner, stainless
steel reflector & end caps.
VTAUT & VTALF = As above except:
aluminised reflector and end caps.
VTCUT & VTCLF = As above except: Stainless
steel IP rated housing, stainless steel brackets,
reflector and end caps
1.3 Heater Suspension
See fig 1b. Attachment to the heater
support lugs should be made by a ‘speed link’,
D shackle or in the case of drop rods, a closed
formed hook. The hanging attachments to over-
head steelwork etc. must be purpose made to
good sound engineering practice or of a propri-
etary type fixing. They must be ade-
quately fixed and designed to carry the whole
weight of the heater. In the event of suitable
roof steelwork being unavailable, additional
steelwork should be fitted to enable vertical
hangers to be used for suspending the heaters.
These methods are illustrated in Figure 1.b. If
there are any doubts as to the strength or
suitability of roof steelwork to which heaters are
to be suspended, please refer to a Consultant,
Architect or owner of the building. The
recommended mounting heights for AmbiRad
heaters are given in the table below.
1.4 Wall Mounting
These radiant tube heaters can be wall
mounted using the appropriate bracket
(AmbiRad part no WMB-13-22-38).
When using the wall mounting brackets the
heater must be inclined at an angle between 30°
and 45°.
Table 1 Angle Mounting
Figure 1.a. Angle Mounting using the Wall
mounting bracket
U Tube Linear
Heater
Size
Required
angle
Chain
length
Eyebolt
position
Chain
length
Eyebolt
position
25 30-35° 10 links 2 7 links 1
45° 13 links 2 9 links 1
Model Recommended Mounting Height (m)
Horizontal Inclined / wall
mounted
25 5.0 - 8.0m 4.0 - 5.0m
1 .
2 . 3 .
E
1. Installation Requirements.
Isolate any electrical supply to the
heater and controller before proceeding.

Doc No. 700025 Page 4 of 32
Figure 1.b. Recommended Methods of Heater Suspension.
Where chain supports have an
angle of inclination greater
than 15° an equal and opposite
support is recommended.
Vertical suspension chain ideal.
Where supports are inclined,
maximum recommended angle
of inclination is 15°.
Ensure burner is also
suspended!!
Shackle method of attachment. Pin must be tightened by pliers.
Drop rod with formed hook. note. hook or eyebolt must be closed tight.
15° max.
ON U TUBE VARIANTS THE HEATER SHOULD SLOPE DOWNWARDS TOWARDS THE RETURN BEND AND ON
LINEAR VARIANTS SHOULD SLOPE DOWNWARDS TOWARDS BURNER BY APPROX. 10mm FOR BOTH
HORIZONTAL AND WALL MOUNTED INSTALLATIONS.
Typical Speedlink attachment.
*These angles to
be equal and not
more than 45°.
Vertical or inclined suspension on this plane is acceptable.
*
*
U TUBE SUSPENSION
*
*
** Alternative suspension
for Linear via single chain.
SINGLE LINEAR SUSPENSION
**
Must be vertical

Doc No. 700025 Page 5 of 32
1.5 Clearance to Combustibles.

The minimum clearances to combustible materials are given in the tables below. These
minimum distances MUST be adhered to at all times.
Figure 2.a Diagram illustrating the clearance to combustibles
VTUT / VTAUT / VTCUT 25
Above Reflector A 180
Above Burner / Heater Outlet B 500
To the Sides C 1000
Below Tubes D 1700
Horizontally from Heater Outlet
(UNFLUED) E 1200
End Wall F 500
A
C
E
F
D
B

Doc No. 700025 Page 6 of 32
VTLF / VTALF / VTCLF 25
Above Reflector A 150
Above Burner B 500
To the Sides C 750
Below Tubes D 1700
Horizontally from Heater Outlet
(UNFLUED) E 1200
End Wall F 500
Above Heater Outlet (FLUED) G 150
Above Heater Outlet (UNFLUED) G1 500
Figure 2.b Diagram illustrating the clearance to combustibles
A
E
F
C
C
D
B
G/G1

Doc No. 700025 Page 7 of 32
to the heater not to apply excessive turning
force to the internal controls.
A flexible hose is installed to allow safe linear
expansion of the heater without creating undue
stress on the gas supply pipe work. It is
therefore important that a tested and certified
hose assembly made to ISO 10380 2003,
supplied with ½” BSP female cone seat
adapters, is installed as per these instructions.
It is also important to ensure that expansion is
taken up in the body of the flexible hose, and
not on its attachment to the pipe work. The cone
seat adapter supplied on one end of the flexible
gas hose provides a `swivel` action, and must
be fitted on the burner using a ½” BSP barrel
nipple to provide ease of disconnection for
future servicing. This assumes that the heater
and fixed gas supply to the isolating valve have
been installed.
The installation layout described below is
the only method recommended by the
institute of gas engineers, the hose
manufacturer, and AmbiRad and must only be
carried out by a qualified/competent gas
engineer.
fig.a fig.c
Arrow denotes
direction of
expansion.
Depending on the specific installation, the
flexible gas hose may be routed to the gas
cock at any of the following angles in relation to
the burner:
Vertical (fig.a)
45° angle (fig.b)
90° angle (fig.c)
Any other position in between these angles is
acceptable.
A clearance distance ‘x’ of min 200mm
must be observed to allow side door
access .
Care must be taken to observe the minimum
pipe bend diameter (minimum 250mm,
maximum 350mm) & pipe expansion distance
(minimum 30mm, maximum 70mm) as shown in
fig.e.
Maximum bend diameter for the 1000mm
hose is 450mm.
The correct installation as shown will allow
for approx 100mm of movement due to
expansion.
x x
fig.b
fig.d
1.6 Gas Connection and Supply
Before installation, check that the local
distribution conditions, nature of gas
and pressure, and adjustment of the
appliance are compatible.
A competent or qualified engineer is required to
either install a new gas meter to the service
pipe or to check that the existing meter is
adequate to deal with the rate of gas supply
required. Installation pipes should be fitted in
accordance with BS 6896:2005, so that the
supply pressure, as stated in Table 4 will be
achieved. It is the responsibility of the
competent engineer to ensure that other
relevant Standards and Codes of Practice are
complied with in the country of installation.
Pipes of smaller size than the heater inlet gas
connection must not be used. The complete
installation must be tested for soundness as
described in the country of installation.
The gas union service cock MUST be
fitted in the gas supply close to the
heater, but not onto the burner itself.
Take care when making a gas connection
fig.e
300 +/- 50mm
Burner
50 +/- 20mm
Figure 3. Correct Installation of Flexible Gas Connection

Doc No. 700025 Page 8 of 32
1.7 Electrical Connections
This appliance must be earthed.
Supply 230V 50Hz single phase.
Standard heater 241W.
Current rating 1.05 amp max
(inductive).
Fuse: external 3 amp.
All electrical work should be
carried out to IEE standards by a competent
electrician. The electrical connection to the
heater is made by means of a four pin plug-in
power connector. Live, neutral earth & high fire
connections should be made via a flexible
supply cable to the power connector and routed
clear of the heater or tubes.
The flexible supply cables should be of
0.5mm² and comply with BS
6500:2000. The wires in the mains lead
are coloured in accordance with the
following code: Green & Yellow Earth;
Blue Neutral; Brown Live; Black Live
It is recommended the heater or group
of heaters are controlled by
thermostats, a time switch and if
required manual control switches and a
frost thermostat.
We recommend use of AmbiRad approved
controls. Please refer to control manual for
siting and installation details.
Where alternative manufactures controls are
used, please refer to their instructions for their
siting and installation details.
Table 2 Gas Supply Pressures
Gas Category I2H I3P
Gas Type Natural Gas (G20) Propane (G31)
Max Supply Pressure (mbar) 25 45
Min Supply Pressure (mbar) 17 25
Nominal Pressure (mbar) 20 37
Gas Supply Connection R½ ½in BSP External Thread
fig.f fig.g
The methods shown in fig.f and fig.g are unacceptable, due to undue stress on the hose & fittings.
Figure 4.b Typical VTLF/VTALF/VTCLF Wiring Connections
Figure 4.a Typical VTUT/VTAUT/VTCUT Wiring Connections
Fused Spur
Fused Spur
L
Black
L
Brown
N
Blue
E
Green &
Yellow

Doc No. 700025 Page 9 of 32
Figure 5. Internal Burner Wiring Diagram.
1
Gas Control
3 8
10
7
2
9
2
1
Pressure Switch
Power ON (red)
BR
BL
R
GR
Y
GR
NL
230V AC
SUPPLY
F1 N F2
HIGH FIRE
TERMINAL
21
1424
11
A2
1222
A1
High Fire
Relay
COIL
NC
230V AC FAN
TERMINALS
2
1
NL
H
NL
BK
3
EMC FILTER
Low Fire (amber)
4
HT
L
N
E
L
N
TWO-STAGE GAS VALVE 230V
BR
BK
Y
G
COM
NO
High Fire (amber)
BLBR

Doc No. 700025 Page 10 of 32
1.7 Electrical Connections cont`d
AmbiRad Smartcom MZ controller shown.
VT models:
These models are supplied with a loose four
way connector ready to be connected to the
controller as shown in the diagram below
Figure 5a. VT Models.
Note:
If an AmbiRad controller is NOT used, then any
third party controller must be capable of
disconnecting all outputs to the burner in the event
of a fault.
SmartCom Mulitizone
NEUT
LIVE
HEAT 2 OUTPUT
HEAT 1 OUTPUT
LIVE
NEUTRAL
*IMPORTANT*
Add this link wire
1/L 2/N 10 S/R0S/R1 D0 D1 41407 8 925 145 6
NOTES:
BLACK BULB SENSOR may be
placed at a max distance of 100m
from the control unit, using
screened 0.75mm² cable. Wiring
should be kept separate from
mains wiring to minimise noise
pick up. Set within Engineers
functions for remote sensor.
BLACK BULB
SENSOR
CUSTOMER
WIRING
NE
2
E
N
H
G
BR
BK
1
L
NE
21
BURNER MOUNTED
4 WAY CONNECTOR
LOOSE
4 WAY CONNECTOR
(SUPPLIED)
BL
INTERNAL BURNER
CONNECTIONS
KEY:
BL - BLUE
BK - BLACK
BR - BROWN
G - GREEN
EARTH
STUD
3A FUSED SPUR
CUSTOMER
230V AC
SUPPLY

Doc No. 700025 Page 11 of 32
E
N
HLINTERNAL BURNER
CONNECTIONS
G
BR
BK
BL
CUSTOMER
4 CORE FLEX
KEY:
BL - BLUE
BK - BLACK
BR - BROWN
G - GREEN
CABLE GLAND
SUPPLIED
SmartCom Mulitizone
NEUT
LIVE
HEAT 2 OUTPUT
HEAT 1 OUTPUT
LIVE
NEUTRAL
*IMPORTANT*
Add this link wire
1/L 2/N 10 S/R0 S/R1 D0 D1 41407 8 925 145 6
NOTES:
BLACK BULB SENSOR may be
placed at a max distance of 100m
from the control unit, using
screened 0.75mm² cable. Wiring
should be kept separate from
mains wiring to minimise noise
pick up. Set within Engineers
functions for remote sensor.
BLACK BULB
SENSOR
EARTH
STUD
3A FUSED SPUR
CUSTOMER
230V AC
SUPPLY
Figure 5b. VTC Models.
VTC models (carwash):
These models require a four core flying lead to
be connected to the controller as shown in the
diagram below.

Doc No. 700025 Page 12 of 32
1.8 Ventilation Requirements
AmbiRad tube heaters can be operated as
flued or unflued appliances in accordance with
the relevant national requirements in the
country of installation.
1.8.1 Unflued Radiant Heater
Radiant tube heaters can be operated as
unflued appliances so that the concentration of
Carbon Dioxide (CO2) at positions where the
air will be inhaled does not exceed 0.28%.BS
EN 13410:2001 is a guide to achieving this
requirement.
If the building air change rate exceeds 1.5 per
hour or if the heat input is less than 5W/m³, no
additional ventilation is required.
In addition to the ventilation requirements,
consideration needs to be given to the
possibility of condensation forming on cold
surfaces.
It should be noted that the clearance distance
around the burner increases when the unit is
operated unflued (see section 1.6). It should be
ensured that the combustion gases do not
impinge on any combustible materials.
Mechanical Ventilation
Mechanical ventilation must be installed to
meet a minimum of 1.5 air changes per hour
using appropriately sized fans and interlocked
with the heaters.
Natural Ventilation
BS EN 13410:2001 should be used to size air
vents to provide adequate ventilation, an
example of this calculation is given below:
Site Details:
20°c Internal Operating Temperature
0°c Outside Air Temperature
5m between high and low level vents
Following the sizing procedure in BS EN
13410:2001 gives an air exit velocity of 1.6m/s.
This equates to a free area vent at both high
level and low level of 17.36cm²/kW free area.
1.8.2 Flued Radiant Heater
In buildings having an air change rate of less
than 0.5 per hour, additional mechanical or
natural ventilation is required. For detailed
information, please see BS6896:2005 section
5.2.2.2.1
Mechanical Ventilation
Mechanical ventilation must be installed to meet
a minimum of 0.5 air changes per hour using
appropriately sized fans and interlocked with the
heaters.
Natural Ventilation
Low level ventilation openings with a free area of
at least 2cm²/kW shall be provided. See section
5.2.2.2.2.1.
1.9 Flue and Combustion Air Inlet -
Options
Dependent on the type of burner fitted to your
heater it is possible to have configurations of flue
and combustion air inlet options to those shown
overleaf:
• Option 1
For burner with / without flue and / or optional
ducted air inlet refer to Figure 6.
1.9.1 Important Information
1.9.1.1 Option 1
A suitable flue system complying with EN1856-1
(type T250 N1 D Vm L11040 O50) should be
used.
Flue size 125mm diameter twin wall.
Flue systems can run either vertically or
horizontally up to a maximum length of 9.5m
(including up to 2 x 90° bends plus the terminal).
The minimum flue length shall be 1m.
The flue system must be terminated in a
vertical position and in accordance with the
British Standard Code of Practice BS 5440: Part
1 - Installation and maintenance of flues and
ventilation for gas appliances of rated input not
exceeding 70kW net (1st, 2nd and 3rd family
gases), and the flue system manufacturers
instructions as supplied with the flue.
1.9.2 Installation
Connection to an appliance which is not
connected to the fuel supply may be carried out
by a competent person. However, connection to
an appliance that is connected to the fuel supply
must be carried out by a registered installer.

Doc No. 700025 Page 13 of 32
If the flue passes through a wall, ceiling, or
roof made from combustible material then it
has to be sleeved so as to provide a minimum
of a 50mm void between the exterior of the flue
and the internal wall of the sleeve. A minimum
of 50mm must be maintained as a clearance
distance to all other combustible materials.
The manifold should be supported by chain,
stainless steel flexible wire, or other flexible
means from the roof structure to allow
movement caused by thermal expansion.
The maximum distance between supports is
1.5m for horizontal runs.
Wall bands are not load bearing and give
lateral support only. If used, wall bands should
be fitted every 3m on vertical runs to ensure
the system is rigidly held. The system should
be braced immediately below passing through
the roof line to ensure the flashing does not
suffer lateral pressures.
The maximum height unsupported above the
roof line is 1.5m. Where a joint is above the
roofline it should be determined that in extreme
wind conditions this joint would not be over
exerted. If there is any doubt then a guy wire
should be used. Beyond this guy wires should
be installed every meter.
The POCED is capable of withstanding its own
weight when installed in accordance with these
instructions and the Regulations shown below.
The exhaust flue should be adequately
supported from the building structure and
installed in accordance with the British
Standard Code of Practice BS 5440: Part 1: -
Installation and maintenance of flues and
ventilation for gas appliances of rated input not
exceeding 70kW net (1st, 2nd and 3rd family
gases), and the flue system manufacturers
instructions as supplied with the flue.
See reference BS 6896: Condensate drain
pipes must be protected against the effects of
freezing.
1.9.3 Condensation
When designing the flue system the prevention
of the formation and entrapment of
condensation must be a key consideration.
1.9.4 Flue Connection
All pipe lengths and flue gas carrying
components are joined together by a twist lock,
bayonet system. The system should be installed
with the visible male collar pointing upwards, this
is reaffirmed by the directional arrow pointing
upwards, indicating the directional flow of flue
gases. Taping of the joints is unnecessary.
1.9.5 Ducted Air
To prevent water ingress on VTC models it is
necessary to fit ducted air to the burner via the
flange shown in Fig.7 on page 15 of this
document
The ducted air flange is fitted with a flexible tube
and secured with a hose clip as shown in the
picture below.
The other end of the flexible hose connects with
the solid tube of the fresh air intake and secured
with a hose clip.
For dirty or polluted environments it is
recommended that VT models are fitted with
ducted fresh air.
Flange part No. 201447 and 3 off screws part
No. 201091 are available from the manufacturer.

Doc No. 700025 Page 14 of 32
1.10 Technical Details.
Table 3 - General
Heat Input kW Gas
Flowrate
(m³/hr)
Injector
Pressure
(mbar)
Injector
Size
(mm)
Gross Nett
High Low High Low High Low High Low
VT25UT 25.0 17.5 22.5 15.8 2.4 1.7 11.0 6.1 1.8
VT25LI8 25.0 17.5 22.5 15.8 2.4 1.7 10.7 6.0 1.8
VT25LI10-5 25.0 17.5 22.5 15.8 2.4 1.7 10.7 6.0 1.8
Heater
Model
Heater
Model
Size
(h x l x w)
Weight
(Kg)
VT(A)(C)25UT 240x5180 (unflued)x500 60
VT(A)(C)25LI8 390x7867 (unflued)x315 53
VT(A)(C)25LI10-5 390x10467 (unflued)x315 72
Table 4 - Natural Gas (G20)
Heat Input kW Gas
Flowrate
(l/hr)
Injector
Pressure
(mbar)
Injector
Size
(mm)
Gross Nett
High Low High Low High Low High Low
VT25UT 25.0 17.5 23.1 16.2 3.5 2.5 14.9 7.7 1.3
VT25LI8 25.0 17.5 23.1 16.2 3.5 2.5 14.7 7.5 1.3
VT25LI10-5 25.0 17.5 23.1 16.2 3.5 2.5 14.7 7.5 1.3
Heater
Model
Table 5 - Propane Gas (G31)
Table 6 - Dimensional details
No of Injectors 1
Gas Connection ½ in BSP Internal thread
Flue Nominal Bore mm (in) 125 (5)
Fan Type 202490
Fan Motor Details 230 volt 1 phase 50Hz
Fan Rating (A) 1.0

Doc No. 700025 Page 15 of 32
Figure 6. Option 1. Flue Attachment U Tube BurnersFigure 7. Flue/Terminal Attachment Linear Burners
Ventilation requirements are as detailed
in section 1.9
Ducted air must be used on VTC
models, and in locations where there is
airborne dust or where there is a polluted
atmosphere e.g Chlorinated Vapours.
Maximum length = 9m
Minimum diameter = 100mm
Maximum no of bends = 2
Maximum flue run = 9.5m @ Ø125mm
Maximum no of bends = 2
All flues must terminate vertically.
For further information on flue runs, please refer
to section 1.10.1 and BS 5440 pt.1
A 127mm (5ins) Twin Wall Flue System
B Tube to Flue Adaptor 75mm 201881
C Flue Bend 7166
D Two Stage Burner
E Standard end terminal (unflued)201866-SUB
Products of
Combustion
D
B
C
A E
Flued Installation
For unflued installation, fit
standard terminal supplied
using grub screw provided
Firing tube
Flange fitted on
VTC models only.
Flexible hose for
ducted air should
be fitted here to
prevent water
ingress

Doc No. 700025 Page 16 of 32
Products of Combustion
A
B C
D
B D
C
A
Figure 7a.
Fit standard terminal
supplied using grub screw
provided
Figure 7b.
E
A Standard end terminal (unflued)201866-SUB
B Tube to Flue Coupler 75mm 201813
C Flue Bend 202662
D Two Stage Burner
A 127mm (5ins) Twin Wall Flue System
B Tube to Flue Coupler 75mm 201813
C Flue Bend 202662
D Two Stage Burner
E Tube to Flue Adaptor 75mm 201881

Doc No. 700025 Page 17 of 32
2. Assembly Instructions.
2.2.3 Brackets
There can be two types of brackets supplied
with these heaters:
 Type ‘A’ are suspending brackets with
reflector fixing points.
 Type ‘B’ are suspending brackets with no
fixing points.
 Type ‘C’ is a centre bracket to retain the
reflector. (UT model only)
Slide the bracket assemblies along to the tubes
to the marked positions in their correct order as
detailed in the assembly drawings.
Tighten clamping ‘U’ bolt arrangement to tubes
ONLY WHERE STATED on the assembly
drawings.
2.2 Assembly Notes.
2.2.1 Tubes
Identify and position tubes on trestles. For
aesthetics it is advisable to position the tube
seam and coupling fastener so that these
cannot be seen from beneath the heater. Mark
out the position of the bracket centres from the
dimensions shown on the assembly drawings.
2.2.2 Turbulators
Insert turbulators into the tubes ensuring the
correct length and quantity are inserted into
their respective correctly identified tube as
detailed in the assembly drawings.
PLEASE READ this section prior to
assembly to familiarise yourself with the
components and tools you require at the
various stages of assembly. Carefully open the
packaging and check the contents against the
parts and check list.
The manufacturer reserves the right to alter
specifications without prior notice.
Please ensure that all packaging is
disposed of in a safe environmentally
friendly way.
For your own safety we recommend the
use of safety boots and leather faced
gloves when handling sharp or heavy items. The
use of protective eye wear is also
recommended.
Pozidrive
Screwdriver
Trestles
Leather
Faced
Gloves
4 & 5mm
Allen
Keys
Tape
Measure

13mm
Socket
Wrench With
Extension
10mm,
12mm &
13mm
Spanners
2.1 Tools Required.
The following tools and equipment are advisable
to complete the tasks laid out in this manual.
Please read these assembly notes in
conjunction with the correct assembly
drawings (figs 9 to 11).
Suitable alternative tools may be used.

Doc No. 700025 Page 18 of 32
Slide the next reflector through the brackets and
overlap the existing reflector until the locating
slots line up with the same bracket fixing points
Secure overlapped reflectors to bracket using
M6 nuts, bolts and flat mud washers.
2.2.7 End Caps.
On VTUT models only, position the end cap
with no tube holes beneath the reflector profile
at the U bend end with the end cap flanges
facing inwards. Fasten to reflector using M5 pozi
set pin and ‘Z’ clips. Position the end cap with
tube holes beneath the reflector profile at the
burner end with the end cap flanges facing
inwards. Fasten to reflector using M5 pozi set
pin and ‘Z’ clips.
On VTLF models only, position ONE end cap
beneath the reflector profile at the open end with
the end cap flanges facing inwards. Fasten to
reflector using ‘Z’ clips. Position the other end
cap beneath the reflector profile at the burner
end with the end cap flanges facing inwards.
Fasten to reflector using ‘Z’ clips.
2.2.4 Couplers.
For VTLF tube heaters only. For joining
radiant tubes, locate and position tube couplers
at the end of the tube so that the socket heads
are facing outwards. Tighten clamping bolt
arrangement to secure ensuring the bolts are
not over tightened.
For VTUT tube heaters only. For joining U
bend, locate and position tube couplers at the
end of the tubes so that the socket heads are
facing outwards.
Do not fully tighten at this stage.
2.2.5 U Bend.
For VTUT tube heaters only. Slide U bend
into the open end of the couplers. Tighten all
four clamping bolts to provide a tight grip
between tubes & U tube section.
To avoid damaging the heater whilst
installing we recommend the heater
chassis be suspended prior to fitting reflectors.
2.2.6 Reflectors.
After removing the protective plastic coating,
slip the reflector through the brackets until the
locating slots are aligned with the type A
bracket fixing points.
Note:
UT models do not have type A brackets. The
reflectors bolt to the central type C bracket. See
Fig. 7 (assembly diagram)
All reflectors must be positioned/
attached to the brackets exactly as
detailed in the assembly drawings.
Remove the protective plastic coating.
2 x ‘Z’ clips
End Cap
M5 set pin
These holes -
Burner end only
UT models
LF models

Doc No. 700025 Page 19 of 32
On VTUT Flued installations, fit flue bend to
heater tube with coupler supplied. Fit adapter to
flue bend then fit twin wall flue to adapter. Do
not silicone seal!
On VTUT Unflued installations, fit flue bend to
heater tube with coupler supplied. Fit standard
terminal as supplied onto open ended tube.
Secure with grub screw.
Do not silicone seal
2.2.10 Detailed Assembly Drawings
The following pages show the technical
dimensional details of the VT range of heaters.
Please note the heater type, length and
reference number from the delivery/advice note
before identifying the correct model drawing.
2.2.8 Burner Assembly.
On VTUT only, slide the burner assembly onto
the RIGHT HAND TUBE when viewed from
above, ensuring it is fully engaged. Secure with
grub screws.
Do not silicone seal!
On VTLF only, slide the
burner assembly onto
the INLET END OF THE
TUBE ensuring it is fully
engaged. Secure with
grub screws.
Do not silicone seal!
2.2.9 Flue/Terminal
Outlet.
On VTLF Flued installations, locate
adjustable tube-to-flue connection (supplied
optionally) onto open ended tube. Rotate to
required orientation Secure with clamp screw.
Do not silicone seal!
On VTLF Un-flued installations, locate
standard terminal as supplied onto open ended
tube. Secure with grub screw.
Do not silicone seal!
2 x ‘Z’ clips
End Cap
Tube-to-flue

Doc No. 700025 Page 20 of 32
Figure 7. Vision Heater Assembly: Models VTUT/VTAUT/VTCUT U tube 25kW.
FIGURE 1
FIGURE 1
M6
FIGURE 2
FIGURE 3
SEE FIGURE 1SEE FIGURE 2
VT25UT
5180
25 35
1935 2293
225