Nortek Reznor 85 User manual

Oil Fired
Floorstanding Heaters
Two Stage, Low Nox Cabinet Heater
WARNINGS
Reznor 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 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 (Industrial & Commercial) 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.
Reznor® Is a registered trademark of Nortek Global HVAC, LLC.
INSTALLATION AND OPERATING MANUAL
ErP
2018 Part No˚ D301029 Issue C

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Any reference made to Laws, Standards, Directives, Codes of Practice or other recommendations governing
the application and installation of heating appliances and which may be referred to in Brochures, Specications,
Quotations, and Installation, Operation and Maintenance manuals is done so for information and guidance purposes
only and should only be considered valid at the time of the publication. The Manufacturer cannot be held responsible
from any matters arising from the revision to or introduction of new Laws, Standards, Directives, Codes of Practice or
other recommendations.
Bio fuel statement - All our oil red heater products are congured for use on both Class D light distillate fuel oil.
As a result of recent changes made to European legislation regarding the specication of class D heating oil to allow
for the inclusion of 7% FAME (Fatty Acid Methyl Ester) i.e. bio fuel and effective from early 2011, all oil red air heater
products and installations maybe affected.
From April 2011 all our oil red cabinet heaters will be tted with Riello burners which are bio fuel compatible for
blends up to 10%.
Please note that the use of bio fuels may give rise to a number of installation issues, to both new and existing plant
which could affect the warranty of the burner. We recommend that you familiarise yourself with current information
from both the burner manufacturer Riello and OFTEC.
Important notice to installers
Installers should satisfy themselves that the oil pipework installation is carried out in accordance with all
current legislation, Codes of Practice and recommendations .

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1. Installation Requirements. 6
1.1 Compliance notices 6
1.2 Certicates of conformity 7
1.3 General product information 7
1.5 Delivery and pre-installation checks. 8
1.6 Warranty 8
1.7 Health and Safety 9
1.8 Location / Positioning 9
1.9 Fuel supply - general 10
1.9.1 Fuel 10
1.9.2 Storage tank 11
1.9.3 Single pipe system (gravity feed) 11
1.9.4 Two pipe system 11
1.9.5 Pressurised ring main system 12
1.9.6 Pipe work and ttings 12
1.10 Electrical supply 15
1.11 Air supply 15
1.11.1 Heaters installed within the heated space. 15
1.11.1.1 Natural Ventilation Openings to the Heated Space. 16
1.11.1.2 Mechanical Ventilation to the Heated Space. 16
1.11.2. Heaters Installed within a Plant Room or Enclosure. 16
1.11.2.1 Natural Ventilation Openings to Plant Rooms 17
1.11.2.2 Natural Ventilation Openings to Enclosures 17
1.11.2.3 Mechanical Ventilation to a Plant Room or Enclosure. 17
1.12 Air distribution system 18
1.13 Flue system. 18
1.14 Dimensions 22
1.15 Technical Details 26
2. Installation. 28
2.1 Packaging/siting 28
2.3 Minimum clearances 28
2.4 Assembly 28
2.5 Flue Installation 28
2.6 Oil Installation/connection 29
2.7 Electrical Installation/connection 29
2.8 Air Distribution Installation 29
2.9 Warm Air Registers 30
2.10 Heater Control Installation 30
3. Commissioning. 48
3.1 Commissioning - Pretest 48
3.2 Commissioning - Ignition 49
3.3 Commissioning - air delivery system 50
3.4 Commissioning - hand over 50
Contents Page

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4.0 Servicing. 51
4.1 Planned Servicing 51
4.2 Servicing Procedure - Major Component Parts 51
4.2.1 Flue 51
4.2.2 Main Fan Motor 52
4.2.3 Main Fan 52
4.2.4 Pulleys 52
4.2.5 Fan Belts 53
4.2.6 Heat Exchanger 53
4.2.7 Electrical Supply 53
4.2.8 Oil Supply 53
4.2.9 Burner 54
4.2.10 Air Delivery System 54
4.2.11 Report 54
4.3 Service Re-commissioning 54
5 Parts Lists 55
6. Fault Finding Guide 60
7. Replacement Parts. 63
7.1 Bur n er 63
7.2 Controller 63
7.3 Electrode Assembly 63
7. 4 N oz z le 64
7.5 Photocell 64
7.6 Oil Pump 64
7.7 Contactor/Overload 65
7.8 MCB 65
7.9 Fan/Limit Stat Assembly 65
7.10 Fan Belts 66
7.11 Blower Motor 66
7.12 Fan Blower 66
8. User Instructions 67
8.1 Commissioning and hand over 67
8.2 Servicing 67
8.3 Start Up Procedure 67
8.4 Stop procedure 67
8.5 Shut down procedure 68
8.6 Ventilation only 68
8.7 Lockout situations 68
Contents Page

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Introduction.
Welcome to the Oil Fired Cabinet Heater Range. Local regulations may vary in the country of use and it is the
installers responsibility to ensure that such regulations are satised
All installation, assembly, commissioning and service procedures must be carried out by suitable qualied competent
persons to the statutory regulations in the country of use.
When installing, commissioning and servicing is undertaken on these heaters due care and attention is required to
ensure that working at height regulations are adhered to at the mounting heights specied.
All Dimensions shown are in mm unless
PLEASE READ this document prior to installation and use. The safety of this heater is guaranteed only by the
correct usage in accordance with these instructions, therefore it is recommended that they are retained for
future reference.
The manufacturer reserves the right to alter specications without prior notice.

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1. Installation Requirements.
1.1 Compliance notices
The Oil Fired Cabinet Heater range detailed herewith are manufactured within a strictly controlled quality environment
within the parameters of ISO 9001.
These instructions are only valid if the following country code is on the appliance GB. IE. If this code is not present
on the appliance, it is necessary to refer to the technical instructions which will provide the necessary information
concerning the modication of then appliance to the conditions of use for the country.
The Oil Fired Cabinet Heater range have been tested and assessed for compliance with the following European
Directives.
• Machinery Directive: (2006/42/EC)
• Low Voltage Directive: (2006/95/EC)
• Electromagnetic Compatibility Directive: (2004/108/EC)
• Product Liability Directive: (85/374/EEC)
The manufacturer has taken reasonable and practical steps to ensure that all Oil Fired Cabinet Heaters are safe and
without risk when properly used. These heaters should therefore only be used in the manner and purpose for which
they were intended, and in accordance with the recommendations detailed herewith.
The Oil Fired Cabinet Heater range has been designed, manufactured, assembled, inspected, and tested, with safety
and quality in mind, there are certain basic precautions which the installer and user should be aware of, and they are
strongly advised to read the appropriate sections of the information pack accompanying the heater, prior to installation
or use.
The manufacturer supports all new products being supplied to their customers with a comprehensive information
pack; this clearly denes mandatory instructions for the safe installation, use, and maintenance, of the appliance(s).
Where proprietary items are incorporated into any Oil Fired Cabinet Heaters, detailed information and instructions are
also provided as part of the information pack.
It is the responsibility of the installer, owner, user, or hirer of Oil Fired Cabinet Heaters to ensure that they are familiar
with the appropriate information/manuals supplied by the manufacturer and the safety instructions. In addition,
operators must be suitably trained in the use of the appliance so as to ensure its continued safe and efcient use.
The manufacturer has a commitment to continuous improvement and therefore reserve the right to amend or
change the specication of Cabinet Heaters subject to compliance with the appropriate European, national and local
regulations
Contained within the text of the manual, the words ‘Caution’ and ‘Warning’ are used to highlight certain points.
CAUTION
Caution is used when failure to follow or implement the instruction(s) can lead to premature failure or damage
to the heater or its component parts.
WARNING
Warning is used when failure to heed or implement the instruction(s) can lead to not only component damage,
but also to a hazardous situation being created where there is a risk of personal injury.

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The Oil Fired Cabinet Heater range conform to the following harmonised standards:
BS EN 292-1
Safety of Machinery - Basic Concepts, General Principles for Design Basic terminology, methodology BS EN 292-2
BS EN 292-2
Safety of Machinery - Basic Concepts, General Principles for Design Technical Principles and Specications
BS EN 60204-1
Safety of Machinery - Electrical Equipment for Machines Specication for General Requirements
BS EN 60335-1
Safety of Household and Similar Electrical Appliances General Requirements
BS EN 55014
Limits and methods of measurement of radio disturbance characteristics of electrical motor-operated and thermal
appliances for household and similar purposes, electrical tools and similar electric apparatus
BS EN 50165
Electrical Equipment of non-electric heating appliances for household and similar purposes, safety requirements
1.2 Certicates of conformity
Certicates of conformity are available from the manufacturer, address details are shown on the back page.
1.3 General product information
The Oil Fired Cabinet Heater models have an output range from approximately 32.0 kW to 381kW, and are available
in a conguration that will allow for down ow, horizontal, or oor mounting.
The units can suit either ducted applications, or be used as free blowing units, but each heater must be connected to
its own individual open ue.
Each heater is tted with a forced draught burner which has been test red and pre-set prior to despatch. The safety
functions of the burner are by way of a fully sequential control box tted to the burner.
Neither asbestos nor soft soldered joints are used in the construction or manufacture of The Oil Fired Cabinet
Heater range. The materials selected for use can withstand the mechanical, chemical, and thermal stresses
which they will be subject to during foreseen normal use when installed in accordance with the manufacturers
recommendations.
1.4 General requirements
CAUTION
Ensure the fuel supply is in accordance with the manufacturer’s recommendations and is as stated on the
appliance data plate.
CAUTION
Installation, commissioning, and servicing must only be carried out by appropriately qualied and competent
persons.
WARNING
Unauthorised modications to the appliance, or departure from the manufacturers guidance on intended use,
or, installation contrary to the manufacturers recommendations may constitute a hazard.
To ignore the warning and caution notices, and to ignore the advice from the manufacturer on installation,
commissioning, servicing, or use, will jeopardise any applicable warranty, moreover, such a situation could
also compromise the safe and efcient running of the appliance itself, and thereby constitute a hazard.

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The installation of the appliance must meet all the relevant European, national, and local criteria.
Prior to installation the following points should be considered;
• The position of the heater for the optimum efcient distribution and circulation of warm air.
• The position of the heater relative to the route of the ue
• The position of the heater relative to the supply of fuel
• The position of the heater relative to the electrical services, and if appropriate, any additional controls.
• The position of the heater relative to the supply of fresh air
• The height if applicable at which the heater is to be mounted and potential stratication /circulation problems.
• The position of the heater relative to service and maintenance requirements
CAUTION
The heater must not be installed within an area where the conditions are unsuitable, e.g. where the atmosphere
is highly corrosive, has a high degree of salinity, or where high wind velocities may affect burner operation.
Suitable protection should be provided for the appliance when it is located in a position where it may be
susceptible to external mechanical damage from; for example, fork lift trucks, overhead cranes etc.
1.5 Delivery and pre-installation checks.
The heater is supplied wrapped in heavy duty protective polythene. On receipt of the heater, the following checks
should be carried out;
• The model is as per order.
• That it is undamaged.
• That it is suitable for the fuel supply.
• That it is suitable for the electrical supply
If any of these points are not satised then contact should be made with the suppliers sales ofce as soon as possible
by telephoning the number shown on the rear page. In the case of claims for damage, this must be signed for as
damaged and reported in writing within 24 hours of delivery, in order to comply with insurance criteria.
1.6 Warranty
The heater is supplied with a 1 year parts and labour warranty and a further year on all parts excluding consumables.
In addition to this there is a 10 year time related warranty on the combustion chamber.
The warranty commences from the date of dispatch from the manufacturer, and is subject to the terms detailed within
the Manufactures ‘conditions of business’.
Note (i) The warranty may be invalidated if …
• The installation is not in accordance with the general requirements of this manual.
• The ue arrangement and air supply for the heater are not in accordance with the manufacturers recommendations, codes of practice, or
similar standards.
• Air ow through the heater is not in accordance with the manufacturers technical specications.
• Internal wiring on the heater has been tampered with or unauthorised service or repairs undertaken.
• The main electrical supply input to the heater has been interrupted during the heating mode.
• The heater has been subject to and affected by the ingress of water in any form.
• The heater is not operated at the rating(s) laid down in the manufacturers technical specications.
• The heater has not been operated or used within the normal scope of its intended application.
• The manufacturer’s recommended minimum service requirements have not been complied with

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Note (ii) All warranty claims must contain the following info to enable processing to take place
• Heater model
• Heater serial number
• Order reference/date of order, together with full installation details (name and address)
• Details or symptoms of fault
• Installers name and address.
Faulty parts must be returned to the supplier, the address of which is provided at the rear of this manual.
Any such parts will undergo inspection to verify the claim. Replacement parts supplied prior to this may be charged,
and a credit supplied upon subsequent validation of the warranty claim.
Consumable items are specically not included within the scope of the warranty.
Note (iii) Notication is required immediately a fault is suspected.
The manufacturer will not accept responsibility for any additional damage that has been caused, expense incurred, or
consequential loss resulting from any failure of the heater(s).
1.7 Health and Safety
WARNING
The Oil Fired Cabinet Heater range must be installed in accordance with the current OFTEC regulations for oil
red products 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: (Industrial & Commercial) and any other relevant British
Standards and Codes of Practice by a qualied 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.
CAUTION Before using this appliance:
• Check that the voltage indicated on the type plate corresponds to the mains supply voltage.
• Ensure that the heater has been securely fastened in its nal mountain position.
WARNING
UNDER NO CIRCUMSTANCES should any item be placed on or above any part of the heater, whether the heater
is being used or not. This appliance must be earthed.
1.8 Location / Positioning
WARNING
All of the basic criteria must be satised prior to commencing installation and commissioning, additionally, the
Oil Fired Cabinet Heater must be positioned and installed so as to comply with all the relevant standards and
guide lines (see section 1.1), as well as meeting national and local re regulations and insurance criteria,
especially if it is proposed that the heater is to be installed within a special risk area (e.g. proximity to where
petrol engined vehicles are stored or parked, where cellulose spraying takes place, where woodworking
machinery is operated, etc,).
Indirect heaters must not be located in hazardous areas, however, it is permissible for the heater to supply air to such
areas.
The heater must not be installed within an environment where there is a high concentration of chlorides, uorides,
salts, or other aggressive or volatile chemicals/compounds. Nor should the heater be positioned where the burner
could be adversely affected by high winds or draughts.
The location chosen for the heater must allow for the tting of an effective ue system.

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The location must also allow for adequate clearance for the air supply, return air circulation, oil supply and electrical
supply, whilst also providing good and safe working access. The heater must be installed on a at and level surface
made from non-combustible material, which is sufciently robust to withstand the weight of the heater and any
ancillary equipment. Any combustible material adjacent to the heater or ue system must be so placed or shielded so
that its surface temperature does not exceed 65°C.
In areas where it is proposed that more than one heater is to be installed, a general scheme of circulation should be
drawn up and maintained, thereby offering the best heat distribution
All Oil Fired Cabinet Heaters are tted with a pressure relief facility, this is incorporated into the design of the ue gas
exit duct.
Care should therefore be taken in siting service connections and controls well away from the pressure relief vent.
WARNING
Under no circumstances must the pressure relief be restricted, blocked, or have the free exit of exhaust gas
impaired or re-directed.
1.9 Fuel supply - general
The Oil Fired Cabinet Heater range are all manufactured and pre-set for use with 35 second gas oil delivered to the
burner via a suitable piped system from the oil storage tank.
WARNING
Galvanised or plastic pipe work and ttings must not be used. (See BS 5410 Part 1 1997)
The constraints of the application will, to a large extent, determine whether it is preferable to use a single pipe gravity
feed system, or whether the two pipe pumped system is more appropriate.
Where more than one appliance is to share a common supply it will be necessary to use a pressurised ring main
system.
All pipe work must be constructed and installed so that it does not permit the ingress of air.
The construction, size, and position of the oil storage tank must take account of the current regulations, as well as
suiting the requirements of the installation.
Please refer to pages 9 and 10 for additional information.
CAUTION
On pumped systems always check that the pump is correctly set up prior to running, and always ensure that
valves are open allowing a free ow of oil through the system.
1.9.1 Fuel
In order to promote trouble free operating it is necessary that the oil within the storage tank and oil line does not fall
below the cold lter plugging point (cfpp), in this country and with class D fuel (also referred to as gas oil). The critical
temperature is -4°C for this summer grade.
The cfpp critical temperature for the winter grade is -12°C. If summer grade fuel is stored for winter use in areas prone
to severe frosts and low temperatures it will be necessary to insulate or even heat the supply tank and pipe work.
The fuel supplier should be contacted prior to installation so that any requirements concerning delivery,
transport, storage and use can be addressed before work commences.
The inlet pump pressure must not exceed a maximum of 0.4 bar, this is because beyond this point gas is liberated
from the oil.

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1.9.2 Storage tank
An externally painted steel storage tank to BS 799 part 5 1987 or a medium density polyethylene oil tank OFTEC
certied to OFS T-100 may be used. Local, national, European and re regulations must also be complied with and
must include:
• A fuel level gauge (not made from glass) a vent pipe with a diameter greater than that of the ller and featuring a weatherproof termination.
• A sludge valve.
• An outlet valve situated at the opposite end of the tank to the sludge valve.
• A ller pipe connection situated at the opposite end to the outlet valve.
The size of the storage tank must take account of the estimated consumption and any quantity price breaks offered by
the oil supplier.
It is preferable to install the tank outside, however, if this is not practicable and the tank has to be installed indoors
advice must be sought about its siting, especially so far as re regulations are concerned.
If a separate re resistant chamber cannot be provided for indoor installations, a catchment pit with a capacity 10%
greater than that of the storage tank must be provided
Storage tanks can if necessary be sited on a roof, but this is subject to special regulations as well as local authority
approval and compliance with re regulations, reference to BS 5410 part 2 1978 & part 1 1997 is strongly suggested.
It is advisable to leave the tank unpainted on the inside, but to paint the outside with a proprietary grade of anti-
corrosive paint.
WARNING
A galvanised or open topped tank is strictly not allowed.
All oil storage tanks require a bund
The Control of Pollution Regulation (Oil Storage) 2001 should be consulted prior to installation.
1.9.3 Single pipe system (gravity feed)
For installations where the oil tank is 200mm or more above the level of the fuel pump the principle of gravity feed
may be used.
The draw off point for the supply to the burner must not be positioned any lower than 100mm above the bottom of the
tank.
Where a return valve is tted this must be tamper proof to prevent inadvertent operation.
CAUTION
If the valve is closed when the pump is running the oil pressure can be increased sufciently so as to cause
damage to the seals within the pump.
The return oil should preferably be discharged through an elbow onto a tank plate situated within the tank, this should
be positioned so as not to introduce air or air bubbles into the draw off pipe.
1.9.4 Two pipe system
This is used where the oil storage tank is lower than the pump.
Access for the fuel feed to the burner should be via a suitable tapping made in the top of the tank, and the fuel feed
pipe should extend to not less than 100mm above the bottom of the tank.
A none return valve with a metal to metal seat should be tted, especially if the return pipe work is terminated at a
level above the draw off tube. The non- return valve must be removable for service and maintenance purposes, and
the return pipe from the pump must therefore be extended down into the tank to the same level as the suction pipe.

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The presence of a tamper proof isolating valve tted within the return pipe is only required if there is a risk that oil will
siphon out of the tank if the return pipe is disconnected at the pump during maintenance or servicing and if the none
return valve has been omitted.
1.9.5 Pressurised ring main system
This system is used to supply a number of units from a common storage tank. A booster pump is used to provide the
pressure to push the oil around the ring main and back to the tank.
Pressure reducing valves should be tted on the delivery pipe to each heater to ensure that the pressure at the burner
pump is less than 6 psi.
CAUTION
The internal by-pass plug must be removed from the burner pump when used in a pressurised ring main
application.
1.9.6 Pipe work and ttings
WARNING
Galvanised or plastic pipe work and ttings must not be used. (See BS 5410 Part 1 1997)
CAUTION
All joints must be sealed properly, if necessary using PTFE tape or other approved sealing media.
The pipe work must be effectively sealed so as to prevent the ingress of air.
It is advisable to check all pipe work prior to installation to ensure that there is no loose debris or scale present.
Black iron pipes can be hammered to assist in the removal of these contaminants.
The oil feed to each heater must be tted with a re check valve and isolating valve.
CAUTION
The re check valve must be operated by way of a fusible link positioned so that it is above the burner.

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Typical arrangement of oil storage tank and single pipe system
Pressurised oil feed system
Burner oil pump details for heater models 30 - 180 oil lines
L metres
H(m) 8mm I.D 10mm I.D
0.5 10.0 20.0
1.0 20.0 40.0
1.5 40.0 80.0
2.0 60.0 100.0

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Burner oil pump details 205 - 375 suction feed
Burner oil pump details for heater models 30 - 180 oil lines
L metres
H(m) 8mm I.D 10mm I.D
0.5 5.0 10.0
1.0 10.0 20.0
1.5 15.0 30.0
2.0 20.0 40.0
Burner oil pump details 205-375 gravity feed from bottom of tank
L metres
H(m) 8mm I.D 10mm I.D
0.0 35.0 100.0
1.0 30.0 100.0
1.0 25.0 100.0
1.5 20.0 90.0
2.0 15.0 70.0
3.0 8.0 30.0
3.5 6.0 20.0

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1.10 Electrical supply
Wiring external to the cabinet heater must be installed in accordance with any local, national, and European
regulations, as well as meeting the appropriate requirements of IEE regulations.
CAUTION
The means of connection to the main electrical supply must allow for complete electrical isolation of the heater,
furthermore, in the case of a unit wired for a three phase supply, the supply should only be used to serve the
heater itself and no other plant or equipment. The position of the isolation switch must be such that it is
adjacent to the heater and easily accessible at all times. In addition, the isolator itself must have a contact
separation of not less than 3mm.(As per BS5991 clause 20.2).
The Control fuse ratings are detailed on the appliance data plate.
WARNING
Ensure that the electric and oil supplies are turned off before any electrical work is carried out on the heater.
CAUTION
Ensure that wiring cannot make contact with any surfaces liable to be subject to high temperatures or where
the insulation of the wiring could be impaired as a result of such contact.
WARNING
All cabinet heaters must be earthed.
CAUTION
The main electrical supply must not be switched off or disconnected as a method for stopping the heater, the
exception to this is in an emergency, or during servicing, when the heat exchanger has been allowed to cool
sufciently to prevent any damage from occurring. Claims for damage will not be considered if they have
resulted from incorrect wiring or the incorrect use of the heater.
1.11 Air supply
Consideration must be given to the provision of air for the purposes of combustion and ventilation of the heated
space, plant room or enclosure where heaters are to be installed.
It is strongly recommended that BS6230 is referred to for further information concerning ventilation
requirements
Where mechanical ventilation is used it is a requirement that the inlet is of the mechanical type, and the outlet is
either mechanical or natural.
1.11.1 Heaters installed within the heated space.
Where heaters are installed within the space to be heated (i.e. not a plant room or enclosure) then:
Combustion air or heater related ventilation air will not be required if -
The design air change rate of the
heated space is 0.5 air changes
per hour or greater
The design air change rate may be
satised by natural inltration or by
mechanical ventilation
OR

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The design air change rate of the
heated space is less than 0.5 air
changes per hour
Where the heated space has an air change rate of less
than 0.5 air changes per hour then it will be necessary
to provide either natural ventilation openings to the
heated space (section 1.11.1.1. refers) or the mechanical
ventilation of the heated space (section 1.11.1.2. refers)
1.11.1.1 Natural Ventilation Openings to the Heated Space.
If the heated space design air change rate is less than 0.5 air
changes per hour then provision for low level natural ventilation
openings will only be necessary.
The minimum free area of the low level natural ventilation opening
shall be:
• 2cm2 for each kW of rated heat input
The low level natural ventilation opening should be situated on an
external wall and be within 1000 mm of oor level.
The following table provides specic data for each heater model as
Combustion and General ventilation will be required if -
OR
Minimum Free Area of ventilation opening
Model High Level cm² Low Level cm²
30 None 64
40 None 97
60 None 127
85 None 193
120 None 257
135 None 291
180 None 386
205 None 460
235 None 515
300 None 623
375 None 847
1.11.1.2 Mechanical Ventilation to the Heated Space.
In the event that the heated space has a design air change of less than 0.5 air changes per hour and that installer
prefers to mechanically ventilate the heated space rather than provide ventilation openings then:-
• The heated space needs to be mechanically ventilated so that the design air change is 0.5 air changes or greater.
• It is a requirement that the mechanical ventilation shall be of the ‘input’ type with either natural or mechanical extraction.
• Systems of mechanical extraction with a natural inlet shall not be used.
It is necessary to provide an automatic means to safely inhibit heater(s) operation should mechanical air supply fail for
any reason.
1.11.2. Heaters Installed within a Plant Room or Enclosure.
A plant room means a room housing the heater plant and probably other items of building service plant and would
generally have generous space for maintenance.
An enclosure is where the heater is installed within a compartment or conned area where space is limited.
Where heaters are installed within a plant room or enclosure then provision for both combustion air and air for general
ventilation will be required by means of high and low level ventilation openings (sections 1.11.2.1 refers to plant room
applications and sections 1.11.2.2 refers to enclosure applications).

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Minimum Free Area of ventilation opening
Model High Level cm² Low Level cm²
30 64 128
40 97 194
60 127 254
85 193 386
120 257 514
135 291 582
180 386 722
205 460 920
235 515 1030
300 623 1246
375 847 1694
Minimum Free Area of ventilation opening
Model High Level cm² Low Level cm²
30 159 318
40 244 488
60 317 634
85 483 966
120 643 1286
135 726 1452
180 965 1930
205 1152 2304
235 1287 2574
300 1558 3116
375 2118 4236
Mechanical Ventilation Rate
for Plant Room or Enclosure
Model M³/h
30 139
40 206
60 274
85 409
120 567
135 717
180 822
205 987
235 1131
300 1410
375 1830
Alternatively the plant room or enclosure may be mechanically
ventilated (section 1.11.2.3 refers).
1.11.2.1 Natural Ventilation Openings to Plant Rooms
For plant room applications the minimum free area of ventilation
opening shall be:
• At high level 2 cm2 for each kW of rated heat input.
• At low level 4 cm2 for each kW of rated heat input.
The high level ventilation opening should be sited on an external wall
and positioned as high as is practical and always within the top 15%
of the wall height.
The low level natural ventilation opening should be situated on an
external wall and be within 1000 mm of oor level.
The table below provides specic data for each heater model as -
1.11.2.2 Natural Ventilation Openings to Enclosures
For enclosure applications the minimum free area of ventilation
opening shall be:
• At high level 5 cm2 for each kW of rated heat input.
• At low level 10 cm2 for each kW of rated heat input.
The high level ventilation opening should be sited on an external wall
and positioned as high as is practical and always within the top 15%
of the wall height
The low level natural ventilation opening should be situated on an
external wall and be within 1000 mm of oor level.
The table in the next column provides specic data for each heater
model as:-
1.11.2.3 Mechanical Ventilation to a Plant Room or Enclosure.
In the event that the installer prefers to mechanically ventilate the
plant room or enclosure rather than provide ventilation openings
then:-
• The plant room or enclosure needs to be mechanically ventilated at the rate of
4.14 m3/h of fresh air per kW or rated heat input.
• It is a requirement that the mechanical ventilation shall be of the ’input’ type
with either natural or mechanical extraction. Where mechanical extraction is
selected then the extraction rate should be 5%-10% less than the input rate.
• Systems of mechanical extraction with a natural inlet shall not be used
• It is necessary to provide an automatic means to safely inhibit heater(s)
operation should mechanical air supply fail for any reason
The table to the right provides specic data for each heater model as -

Page 18
1.12 Air distribution system
All materials used within the construction of the delivery and return air ducts must not represent a re hazard and
should be made from thermally inert materials. The selection of materials must take account of the environment
into which the heater and its air delivery system is expected to work, it must also take account of the stresses and
loadings placed upon it during its normal working life. Where interjoist spaces are used to route ducting these must be
lined with re resistant insulation material.
In installations where forced recirculation is a feature, a full and unobstructed return air path to the heater(s) must be
provided, with return air grilles connected by ducting directly to the return air inlet on the heater.
The limit for recirculation should not be greater than 85% re-circulated air to 15% fresh air.
Where the heater is installed within a compartment or plant room the return air and discharge air arrangement must
be such that the air circulation fan does not interfere with the operation of the ue. The return air intake and warm air
outlet should therefore be fully ducted to and from the heater, respectively, within the compartment or plant room.
If the inlet air is ducted to the outside, then the lowest edge of the inlet air duct must be at least 500mm above the
outside oor or ground level, it must also be tted with an access point(s) to allow for cleaning and servicing to occur.
The openings in the structure of the plant room, through which the ductwork passes must be of re resistant material
and constructed to prevent the likelihood of any re from spreading.
In ducted applications the ductwork must be designed so as to give a static pressure within the limits stated in section
1.15 of this manual. It should be noted that if the static pressure is too high, nuisance shut-down will occur when the
heater goes out on the overheat limit thermostat, if the static pressure is too low, then damage can be caused to the
fan motor.
Warm air outlets on ducted applications must be such that they cannot be closed or become blocked, which again
would lead to an increase in static pressure and nuisance shut-down. The outlets must not be sited so that warm air
can be discharged onto combustible materials, if necessary, guard rails should be used to ensure that effected areas
are kept clear.
Return air intakes must not be located so that potentially harmful or hazardous contaminated air can be drawn into the
system.
1.13 Flue system.
WARNING
It is essential that the products of combustion are ued to the outside of the building. Each heater must have its
own separate ue, with a ue diameter of not less than is detailed in section 1.15 within this manual.
The minimum vertical length of ue must not be less than 3m. The ue should rise vertically, and the number of bends
should be kept to a minimum.
Flue pipes below a height of 2m should be guarded against the possibility of being accidentally touched when hot by
personnel
It is strongly advised that BS 5854; 1980, and BS 5440; parts 1 and 2, are used as consultative documents
when considering ue requirements.
Care should be taken to ensure that the ue terminal is not situated in a high-pressure area, the proximity of buildings
and other obstacles which will inuence this must be taken into account, preferably at the design stage. See pages 15
& 16
Provision must be made for the disconnection of the ue for inspection and service requirements, and it is strongly
advised that where bends are tted inspection covers are included.

Page 19
The materials from which the ue is constructed must be non-combustible, resistant to internal and external
corrosion, and be capable of withstanding the stresses and loadings associated with normal use.
When designing the ue system the prevention of the formation and entrapment of condensation must be a key
consideration.
Twin wall or insulated systems are recommended, as they tend to inhibit the formation of condensates.
Where condensation is unavoidable traps should be included to encourage the condensates to ow freely to a point
from which they may be released, preferably into a gully. The condensate pipe from the ue to the disposal point must
be made from corrosion resistant pipe of not less than the internal diameter of the drain pipe.
If the ue 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 25mm void between the exterior of the ue and the internal wall of the sleeve. The maximum
permitted temperature of any adjacent combustible material is 65°C. The position of the ue and its terminal should
be such that it does not impair the combustion process.
It should terminate in an exposed position so as to allow the escape and dissipation of ue gases without risk of their
re-entering the property through windows, ventilation ports, etc. The ue should extend to at least 1m above the
height of any object within 3.5m of the terminal. Flue terminals should be tted on all ues, the terminal must be of the
approved type, and have outlet grilles on all sides giving a total free area of at least double that of the ue.
CAUTION
It is imperative that the ue should be properly sealed where it passes through the roof, this can best be
achieved by using the approved method of roof ashing plate and cravat.

Page 20
It should be noted that claims made under warranty and attributed to the ingress of water may not be
considered especially if an approved method of sealing has not been used, or if the design of the ue has not
made provision for possible condensation problems.
Flat roof with parapet
Flat roof envelope method
Flat roof where the ue height is more than 10 Heights (H) away from all structures
Flat roof with ue close to parapet