BENSON
MH300
( OIL FIRED MARQUEE HEATER )
I N S T A L L A T I O N C O M M I S S I O N I N G
S E R V I C I N G
U S E R I N S T R U C T I O N S
Section Contents Page No
1.0 Compliance Notices
4
1.1 Certificates of Conformity 5
1.2 General product Information 5
1.3 General Requirements 5
1.4 Delivery & Pre-installation Checks 5
1.5 Warranty 6
2.0 Location & Positioning
6
2.1 Fuel supply-general 7
2.2 Fuel 7
2.3 Fuel Storage 7
2.4 Single pipe system 7
2.5 Two pipe system 8
2.6 Pipe work & Fittings 8
2.7 Oil installation and Connection 8
2.8 Electrical Supply
8
2.9 Air Supply 9
2.10 Air Distribution 10
2.11 Flue System 11
3.0 Installation
11
3.1 Electrical installation & Connection 11
3.2 Air Distribution 11
3.3 Heater Control Installation 12
4.0 Commissioning 12
4.1 Pre test 12
4.2 Ignition 13
4.3 Air Delivery System 14
4.4 Hand Over 15
5.0 Servicing
15
5.1 Planned Servicing 16
5.2 Servicing Procedure 16
6.0 Fault diagnosis by flow chart 20
7.0 Wiring Diagrams 22
8.0 Technical data 23
9.0 Reference Documents 24
1.0 Compliance notices
The Benson MH 300 oil fired Heater detailed
herewith is manufactured by Benson Heating within
a strictly controlled quality environment within the
parameters of ISO 9001.2000
The Benson MH 300 has been tested and assessed
for compliance with the following European
Directives.
Machinery Directive (89/392/EEC)
Low Voltage Directive (73/23/EEC & 93/68/
EEC)
Electromagnetic Compatibility Directive
(89/336/EEC & 91/31/EEC)
Product Liability Directive (65/374/EEC)
The manufacturer has taken reasonable and
practical steps to ensure that Benson MH 300
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 heaters
have 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.
Benson Heating supports all new products being
supplied to their customers with a comprehensive
information pack; this clearly defines mandatory
instructions for the safe installation, use, and
maintenance, of the appliance(s).
Where proprietary items are incorporated into
Benson Heating products, 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 such products supplied by Benson Heating
to ensure that they are familiar with the appropriate
information/manuals, supplied by the manufacturer,
and that they are suitably aware of the purpose of
the manuals 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
efficient use.
Benson Heating has a commitment to continuous
improvement, and therefore reserves the right to
amend or change the specification of the MH 300
Heater 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 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 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.
The Benson MH 300 Oil fired heaters conform to
the following harmonized standards;
BS EN 292 - Part 1 : 1991
Safety of Machinery - Basic Concepts, General
Principles for Design Basic terminology,
methodology
BS EN 292 - Part 2 : 1991
Safety of Machinery - Basic Concepts, General
Principles for Design Technical Principles and
Specifications
BS EN 60204 - Part 1 : 1993
Safety of Machinery - Electrical Equipment for
Machines Specification for General Requirements
BS EN 60335 - Part 1 : 1988
Safety of Household and Similar Electrical
Appliances General Requirements
BS EN 55014 - 1993
Limits and methods of measurement of radio
disturbance characteristics of electrical motoroperated and thermal appliances for household and
similar purposes, electrical tools and similar electric
apparatus
prEN 50165 - 1995
Electrical Equipment of non-electric heating
appliances for household and similar purposes,
safety requirements
1.1 Certificates of conformity
Certificates are available from the Quality Control
Department at Benson Heating.
1.2 General product information
The Benson MH 300 model has an output of
300kW.
The MH 300 units can suit either ducted
applications, or be used as free blowing units, but
each heater must be connected to its own
individual open flue.
Each heater is fitted with a forced draught burner
which has been test fired and pre-set prior to
dispatch. The safety functions of the burner are by
way of a fully sequential control box fitted to the
burner.
Note
Neither asbestos nor soft soldered joints are used
in the construction or manufacture of the Benson
range of Cabinet Heaters. 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.
1.3 General requirements
Caution
Ensure that the fuel supply is in accordance with
the manufacturer's recommendations and is as
stated on the appliance data plate.
Installation, commissioning, and servicing must
only be carried out by appropriately qualified and
competent persons.
Warning
Unauthorised modifications to the appliance, or
departure from the manufacturers guidance on
intended use, or, installation contrary to the
manufacturers recommendations may constitute a
hazard.
Note
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 efficient running of the appliance itself, and
thereby constitute a hazard.
The installation of the appliance must meet all the
relevant European, National, and Local criteria.
Caution
The heater must not be installed 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,
1.4 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;
a) The model is as per order
b) That it is undamaged
c) That it is suitable for the fuel supply
d) That it is suitable for the electrical supply
If any of these points are not satisfied then contact
should be made with the Sales Office at Benson
Heating as soon as possible by telephoning 01547-
528534. In the case of claims for damage, this
must be reported in writing within 24 hours of
delivery, in order to comply with insurance criteria
1.5 Warranty
The heater is supplied with a 2 year warranty made
up as follows; first year covering parts and labour,
and second year covering parts only. In addition to
this there is also a 10 year time related warranty on
the combustion chamber/heat exchanger. The
warranty commences from the date of dispatch from
the manufacturer, and is subject to the terms
detailed within the Benson Heating 'conditions of
business'.
Note (i)
The warranty may be invalidated if –
a) The warranty registration/commissioning card
has not been completed and returned to Benson
Heating
b) The installation is not in accordance with the
general requirements of this manual
c) The flue arrangement and air supply for the
heater are not in accordance with the
manufacturers recommendations, codes of practice,
or similar standards
d) Air flow through the heater is not in accordance
with the manufacturers technical specifications
e) Internal wiring on the heater has been tampered
with or unauthorised service/repairs undertaken
f) The main electrical supply input to the heater has
been interrupted during the heating mode
g) The heater has been subject to and affected by
the ingress of water in any form
h) The heater is not operated at the rating(s) laid
down in the manufacturers technical specifications
i) The heater has not been operated or used within
the normal scope of its intended application
j) The manufacturer's recommended minimum
service requirements have not been complied with
Note (ii)
All warranty claims must contain the following
information to enable processing to take place;
(1) Heater model
(2) Heater serial number
(3) Order reference/date of order, together with full
installation details (name and address)
(4) Details or symptoms of fault
Faulty parts must be returned to the Knighton
Spares Department, the address of which is
provided on the rear cover 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 specifically not included
within the scope of the warranty.
Note (iii)
Notification 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).
2.0 Location/Positioning
Warning
All of the basic criteria must be satisfied prior to
commencing installation and commissioning,
additionally, the Heater must be positioned and
installed so as to comply with all the relevant
standards and guide lines (see section 9.0), as well
as meeting national and local fire 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 fired 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, fluorides, salts, or other aggressive or
volatile chemicals/compounds.
The location must also allow for adequate
clearance for the air supply, return air circulation, oil
supply, electrical supply, whilst also providing good
and safe working access.
Any combustible material adjacent to the heater or
flue system must be so placed or shielded so that
its surface temperature does not exceed 65
o
C.
Warning
TRANSPORTATION
The heater should be kept in a
position at all times when being transported by
fork lift truck or other mechanical devices
HORIZONTAL
2.1 Fuel supply - general
The Benson MH 300 of oil fired heater 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.
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.
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.
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 flow of oil
through the system.
2.2 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 filter plugging
point (cfpp), in this country and with class D fuel
(also referred to as gas oil). The critical
temperature is -4oC for this summer grade.
The cfpp critical temperature for the winter grade is
-12oC.
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.
Warning
The pump pressure must not exceed a maximum of
0.4 bar, this is because beyond this point gas is
liberated from the oil.
2.3 Storage tank
It is advisable to leave the tank unpainted on the
inside, but to paint the outside with a proprietary
grade of anti-corrosive paint.
A galvanised or open topped tank is strictly not
allowed.
If a medium density polyethylene oil tank is to be
used then it must be OFTEC certified to OFS T-
100.
Local, National, European and Fire regulations
must also be complied with.
2.4 Single pipe system (gravity feed)
For installations where the oil tank is 300mm 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 fitted 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 sufficiently 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.
2.5 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 fitted, 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.
The presence of a tamper proof isolating valve fitted
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.
2.6 Pipe work and fittings
Caution
Galvanised pipe work and fittings must not be used.
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.
Note
The oil feed to each heater must be fitted with a fire
check valve and isolating valve.
The fire check valve must be operated by way of a
fusible link positioned so that it is above the burner.
2.7 Oil Installation/connection
The oil tank must be positioned so that there is a fall
of 7.5mm (+/- 2.5mm) for every 30mm away from
the outlet and towards the sludge/drain valve, which
must be sited at the lowest point in the tank. If the
tank is positioned on supports then there must be an
adequate protective layer between tank and support
to prevent damage or deterioration through
corrosion
It is strongly suggested that reference is made to
BS 5410 ; part 2 ; 1978.
It is also suggested that the installer is familiar with
the detail and requirements contained within
sections 2.1 through to section 2.6 of this manual
prior to commencing installation.
Warning
Prolonged exposure and contact with Gas Oil can
result in the natural oils being removed from the
skin, sensitisation can result in dermatitis.
Always ensure that the appropriate personal
protective equipment is used.
2.8 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.
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.
Warning
Ensure that the electric and oil supplies are turned
off before any electrical work is carried out on the
heater.
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.
All Benson 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 sufficiently 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.
2.9 Air supply
Provision must be made for the existence of an air
supply in order to satisfy both combustion and
ventilation criteria.
It is a requirement that the area where the air heater
is located must have a permanent air vent of
negligible resistance direct to the outside air.
Such air vents must be positioned so as not to
become blocked or flooded, nor should they be
placed so as to introduce undesirable matter (e.g.
flammable, volatile, or aggressive chemicals/
compounds or potentially hazardous or harmful
substances) either direct from the outside, or
through their proximity to an adjacent extraction
system.
Note
It is strongly recommended that BS 6230 : 1991 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.
2.9.1 Heaters installed within the heated
space
Where heaters are installed within the space to be
heated (e.g. not a plant room separate room, or
compartment then
Combustion and general ventilation
is not required if
The combustion air intake is ducted to atmosphere
(i.e. Room Sealed Appliance)
OR
The design air change rate of the building is more
than 0.5 air changes per hour and the volume of the
space is greater than 4.7m
rated heat input
Combustion and general ventilation
is required if
The appliance is not provided with combustion
ductwork e.g. the air for combustion is taken from
the space being heated
3
per kilowatt of the total
And
The building design air change rate is less than 0.5
air changes per hour and the volume of the space is
greater than 4.7m
3
per kilowatt then low level ventilation is required
Where combustion air ventilation is required as
dictated by the previous criteria then that ventilation
can be via permanent ventilation openings / grilles
situated at low level (I.e. below the flue takeoff
spigot ) and with the free area of such grilles as :For heaters with a rated input of less than
60 kW — 4.5 cm
For heaters with a rated input of more than 60 kW
— 270 cm
2
plus for each kW of rated input over the
60 kW threshold an additional 4.5 cm
2
per kW of heat input
2
Or by mechanical input (not extract) ventilation in
association with either mechanical or natural extract
and with a ventilation flow rate of 1.08m
3
/h per kW
of total rated input
Where mechanical extract is used to complement
the above then the extract rate shall be 2.16m
3
/h
per kW of rated heat input
Mechanical ventilation systems where fitted must be
provided with safety interlocks to prevent heater
operation in the event of airflow failure.
2.9.2
Heaters installed Within a Plant Room
Where the heater is installed within a plant
room ,separate room or compartment then
combustion and general ventilation
is always required
Where the combustion air intake is ducted to
atmosphere (i.e. Room Sealed Appliances)
Then that ventilation can be via a permanent
ventilation / grille situated at both low level (inlet)
and high level (outlet) and with the free area of such
grilles as :-
Low level (Inlet)
For heaters with a rated input of less than
60 kW — 4.5 cm
For heaters with a rated input of more than 60 kW
— 270 cm
2
60 kW threshold an additional 2.25 cm
2
per kW of heat input
plus for each kW of rated input over the
2
High Level (Outlet)
For heaters with a rated input of less than
60 kW — 4.5 cm
2
per kW of heat input
For heaters with a rated input of more than 60 kW
— 270 cm
60 kW threshold an additional 2.25 cm
2
plus for each kW of rated input over the
2
Alternatively mechanical input (not extract)
ventilation may be used in association with either
mechanical or natural extract and with a ventilation
flow rate of 2.16m
3
/h per kW of total rated input.
Mechanical ventilation systems where fitted must
be provided with safety interlocks to prevent heater
operation in case of air flow failure
Where the combustion air intake is not ducted to
atmosphere heater installed in flue only
configuration then ventilation can be via a
permanent ventilation opening / grille situated at
both Low level (Inlet) and high Level (Outlet) and
with the free area of such grilles as :-
Low level (Inlet)
For heaters with a rated input of less than
60 kW — 9.0 cm
2
per kW of heat input
For heaters with a rated input of more than 60 kW
— 540 cm
60 kW threshold an additional 4.5 cm
2
plus for each kW of rated input over the
2
High Level (Outlet)
For heaters with a rated input of less than
60 kW — 4.5 cm
2
per kW of heat input
For heaters with a rated input of more than 60 kW
— 270 cm
60 kW threshold an additional 2.25 cm
2
plus for each kW of rated input over the
2
Alternatively mechanical input (not extract)
ventilation may be used in association with either
mechanical or natural extract , and with a
ventilation flow rate of 3.24m
3
/h per kW of total
rated input
Where mechanical extract is used to complement
3
the above then the extract rate shall be 2.06m
/h
per kW of rated heat input
Mechanical ventilation systems where fitted must
be provided with safety interlocks to prevent heater
operation in case of air flow failure
2.9.3 Ventilation Openings and Grilles
Ventilation openings and grilles must communicate
directly with the outside air, be of negligible
resistance and shall be sited so that they cannot
easily be blocked of flooded
Caution
Additionally, an automatic control interlocked to the
burner must be fitted to ensure burner shutdown in
the event of airflow failure or restriction.
2.10 Air distribution system
All materials used within the construction of the
delivery and return air ducts must not represent a
fire 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 fire 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.
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 floor or ground level, it
must also be fitted with an access point(s) to allow
for cleaning and servicing.
The openings in the structure through which the
ductwork passes must be of fire resistant material
and constructed to prevent the likelihood of any fire
from spreading.
In ducted applications the ductwork must be
designed so as to give a static pressure within the
limits stated in section 8 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.
2.11 Flue system
Warning
Each heater must have its own separate flue, with a
flue diameter of not less than 225mm The minimum
vertical length of flue must not be less than 1m.
The flue should rise vertically, and the number of
bends should be kept to a minimum.
It is strongly advised that BS 5854; 1980, and BS
5440; parts 1 and 2, are used as consultative
documents when considering flue requirements.
Care should be taken to ensure that the flue
terminal is not situated in a high-pressure area, the
proximity of buildings and other obstacles which will
influence this must be taken into account,
preferably at the design stage.
Provision must be made for the disconnection of the
flue for inspection and service requirements, and it
is strongly advised that where bends are fitted
inspection covers are included.
The materials from which the flue 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.
3.0 Installation
3.1 Electrical Installation/Connection
Benson MH 300 cabinet heaters are
415V 50Hz 3PH NEUTRAL & EARTH
It is recommended that reference is made to the
wiring diagrams contained within section 7 of this
manual prior to installation or connection to the
supply.
The electrical supply must be as specified and
suitable for the heater, and must be run within
conduit to a point adjacent to the heater, and be
terminated to provide an isolation point that will
prevent remote or inadvertent activation.
Cables, conduit, and fittings that are used to make
the connection between the isolator and the heater
must conform to the appropriate IEE regulations. All
heaters are supplied fused and pre-wired, all must
be earthed.
Final connections for any additional external
controls must be completed on site, and must be
carried out according to IEE regulations.
Separate user information is provided for the time
control unit and the burner, and forms part of the
product information pack which accompanies every
heater when dispatched.
Warning
Always isolate from mains electrical supply before
commencing work on the heater.
Always ensure that the appropriate personal
protective equipment is used.
3.2 Air Distribution Installation
The materials selected must be of low heat
capacity, and it is preferable that all warm air
ductwork is thermally insulated.
Where ducting may be subject to deterioration from
exposure to moisture or high humidity material
selection and insulation are prime considerations.
Joints and seams must be airtight and fastened
securely and designed to remain so, even when
operating at high temperatures.
Adequate support must be designed into the layout
of the ductwork to ensure that the integrity of the
seams and joints is maintained.
The support must be independent and separate
from the heater and the ducting, to allow for
free movement during expansion and
contraction.
Where ducting passes through walls or
partitions sufficient clearance must be left,
irrespective of any fire stop requirement, to
allow for expansion and contraction.
Failure to adhere to these latter two points can
result in the generation and transmission of
excess noise.
Where ducting is installed in concrete flooring
a permanent membrane must be used to
isolate the ducting from the corrosive effect of
the alkaline salts within the concrete.
Care should be taken to ensure that soft
insulation material does not become
compressed and thereby lose its effectiveness.
3.2 Heater Control Installation
Warning
Isolate heater from mains before undertaking
any electrical work.
(a) Ventilation/Heat switch (summer/winter
switch)
(b) Burner High/Low switch
(c) Remote Thermostat Connection
(d) Phase selection Switch
(e) Bulkhead Light Switch
4.0 Commissioning
Note
It is a requirement that only suitably qualified
and competent personnel are allowed to
undertake the
commissioning of the heater.
It is also strongly recommended that prior to
commissioning the engineer familiarises
himself with; the information contained within
the information pack that accompanies the
heater, the heater itself, and with the specific
requirements of the installation/application.
The following checks should be carried out
after the familiarisation process.
Warning
All Heaters undergo a rigorous test programme
prior to being dispatched, whilst such a
programme does involve pre-commissioning
and setting up the heater to operate efficiently
and well within its designed operational limits,
this does not mean that on site commissioning
is less important than might otherwise be the
case. The idiosyncrasies of each installation
can only ever be allowed for, through the use
of thorough on site commissioning carried out
by trained and experienced personnel
equipped with the correct tools and apparatus.
Note
It is strongly recommended that equipment
used for the sampling and analysis of flue
gases is accurate to within +/- 0.1% and
maintained so that it is regularly calibrated.
4.1 Commissioning - Pretest
Check to ensure electrical safety, and inspect
and check the oil installation, testing for leaks.
(a) Ensure that the electrical supply is turned
off.
(b) Ensure that the oil supply is turned off.
(c) Check that all panels and fasteners are
secure and in place.
(d) Check that the heater is installed so that it
is square and that the support is adequate.
(e) Ensure that warm air delivery outlets are
open and that ducting is adequately supported.
(f) Ensure that if filter assemblies are fitted that
they are secure and correctly located.
(g) Check that air inlets are clear and that
return air paths are adequate.
(h) Ensure that the flue is secure, adequately
supported, and that the various joints are
properly sealed.
(i) Check that there is provision for flue gas
sampling and that this sample point can be
plugged and sealed after commissioning.
(j) Check that fan and limit stat settings have
not been disturbed and are as follows
Fan on - 60
Fan off - 30
Overheat limit - 100
o
C
o
C
o
C
Also check that the white button (automatic) is
pulled outward and that the red button (reset)
is pushed inwards to the reset position.
(k) Ensure that the burner is securely attached
to the heater.
(l) Test for electrical earth continuity between
the heater, oil pipe work, and mains supply.
(m) Turn on main electrical supply, select the
following switch settings
Heat/Ventilation - Ventilation
The fan will start enabling fan direction etc
to be verified. Reset on/off switch to off
position.
(n) Turn mains electrical supply to off, replace
and secure lower louver panel covering fan
and motor assembly.
(o) Set thermostat to 'demand' position.
4.2 Commissioning - Ignition
Warning
Do not proceed with commissioning unless all
the criteria detailed within sections 4.0 and 4.1
have been satisfied.
(a) Ensure that the electrical supply is turned
off.
(b) Ensure that the oil supply is turned off.
(c) Select the following switch settings on the
heater
Heat/Ventilation - Heat
(d) Turn on main electrical supply.
(e) Select 'on' position for heater on/off switch.
(f) Check for the following burner sequence
Interval Operand
1 <5s Combustion air damper actuated,
burner fan motor initiates purge
cycle...
2 <15s Solenoid valve opens ignition
transformer provides spark for
burner ignition...
E I T H E R --------
3 >15s Ignition failure caused by oil
starvation resulting in burner lockout/shut-down...
(g) Set heater on/off switch to off position
(h) Attach oil manifold (bleed screw and
pressure gauge)
(i) Open oil supply valves and bleed air from
pipe work and adjust burner oil pressure as per
detailed in burner manual Repeat steps 4.1 q,
and 4.2 c,e,f.
--------- O R ------------
4 >15s Burner ignition.flame detection...
5 <20s Burner ignition cycle complete
Note
It is strongly recommended that the separate
manual concerning the operational details of
the burner supplied with the heater as part of
the information package is studied prior to
commissioning.
Time intervals within the ignition sequence will
vary slightly from one model to another.
Warning
If burner ignition is not satisfactorily
accomplished, commissioning must not
proceed until the reason or fault has been
identified and rectified, if necessary by
reference to the separate burner information or
to section 6 of this manual.
(k) Repeat steps 4.2 c,a,
(l) Repeat steps 4.2 d,e,f, allowing the heater
to reach thermal equilibrium.
(m) Adjust thermostat to its highest setting,
and allow the heater to continue to fire.
(n) Gradually reduce the temperature setting
on the thermostat until the burner shuts down,
(@ < ambient and then gradually increase the
temperature setting on the thermostat until
heat is called for, (@ > ambient) and the
burner automatically re-fires.
(o) Check fan and limit stat by depressing and
holding in the fan motor overload re-set button,
located on the heater electrical panel. The time
between the fan stopping and burner shut
down should be noted, once the burner has
shut down the overload on the motor should be
released.
If the time interval between fan stop and
burner shut down is greater than 90 seconds
further checks should be made.
These are as follows
(i) Check settings on fan and limit stat are
correct, ie, fan on 60oC, fan off 30oC, limit
100oC.
(ii) Check that the position of the unit is
correct, ie, equi-distant between heat
exchanger body and heat shield panel.
(iii) Check integrity of unit, ensuring that
neither the bi-metallic strip nor its casing is
damaged.
(p) Undertake flue gas analysis using
approved and calibrated analysing equipment
recording data on the commissioning card, ie,
CO, CO2, net and gross flue temperatures.
Record burner oil pump pressure, ambient
temperature, barometric pressure, and smoke
reading (0 - 1 Baccarach scale).
Note (i)
The burner air and oil pressure settings should
be only very finely adjusted to achieve a CO2
reading of 12.5%
(+/- 0.5%).
Note (ii)
The gross efficiency must be approximately
80%.
Note (iii)
All Heaters are test fired and precommissioned as part of the manufacturing
process, if however, during on site
commissioning the data are found to be not in
accordance with the manufacturers data, then
the following action is recommended.
* Re-check all readings and calculations.
* Adjust burner as per manufacturers
instructions.
* Consult Benson Technical Department.
(q) Complete commissioning card and provide
operating instructions for the user, high-light
the fact that the manufacturer recommends
that in the interests of safety and efficiency the
heater is serviced on a regular basis only by
qualified and competent persons.
The completed commissioning card must be
returned to Benson Heating Service
Department immediately after the satisfactory
completion of commissioning, failure to do so
can invalidate any subsequent warranty claim.
(s) Set all controls to the requirements of the
user.
4.3 Commissioning - air delivery system
Caution
On ducted applications it is necessary that the
system is balanced in order to optimise the
efficiency of the heater and the air distribution
and delivery system
Failure to balance the system can result in fan
motor overloading and premature component
failure, it can also result in an inefficient
heating/ventilation system.
(a) Check that the amount of fan produced air
volume is in accordance with the heater
specification; if the volume is too great the fan
can be overloaded.
Ensure that the running current is as per that
stated on the heater data plate.
Alternatively, the static pressure should be
measured at the start of the ductwork to
confirm that it is within the permissible
tolerance.
(b) If the current drawn is greater than the
stated running current, in most probability this
will be caused by insufficient static pressure
within the ductwork, in which case system
resistance should be increased through the
introduction of a damper placed as close to the
start of the ductwork as possible, thereby
resulting in a reduction in drawn current.
The damper should be adjusted until the
current is in accordance with that stated on the
data plate.
(c) If the current drawn is too low the duct
outlet grilles will require opening to reduce
static pressure and increase air volume, if this
is not the case overheat cut outs can be
caused.
4.4 Commissioning - hand over
(a) Upon full and satisfactory completion of
commissioning, a record of commissioning
information
(contact, date, etc) should be left with the
heater, a copy of which must also be
forwarded to Benson Heating Service
Department.
(b) The commissioning engineer must ensure
that the user is familiar with the safe and
efficient use of the heater, detailing the
function of all controls, and main components.
(c) The user should be made aware of the
following in particular
(i) Lighting, shutdown, and operational
information.
(ii) Safety features, data plate, and labelling.
(iii) The requirement for regular inspection especially if the heater is within a more
demanding environment - and the need for
regular servicing carried out by competent and
qualified persons.
Caution
After approximately 100 hours of running, the
tension of the fan belts must be checked to
ensure that they are correct and that they have
not stretched. See section 5.2 for further
instructions.
5.0 Servicing
Warning
Servicing must be carried out on a regular
basis, the maximum interval between services
being 1 year. It is a requirement that only
suitably qualified and competent persons are
allowed to undertake servicing.
Before any maintenance or servicing work
is carried out the heater must be shut down
and allowed to cool, and have the oil and
electric supplies to it turned off at the
supply valve and isolator respectively.
Caution
Certain component parts are factory sealed
and are designed so as to be tamper proof.
Usually such items do not require servicing,
and therefore should not be tampered with.
Failure to comply with this can invalidate any
warranty, and can also lead to premature
failure.
The following parts fall within this category:
thermostat, fan and motor.
Additionally, the fan and limit stat has been
factory set, and must not be re-set without
formal consent from the manufacturer.
Reference should be made to the separate
information covering the operational details of
the burner .
Only approved spare/replacement parts can
be fitted, failure to comply with this can
compromise the safe and efficient running
of the heater, and can also invalidate any
warranty claim.
5.1 Planned Servicing
In order to maintain the efficient operation of
the heater it is recommended that the following
planned servicing and preventative
maintenance programme is adopted by the
user.
Quarterly Inspection
(a) Visual inspection of the burner
(b)Clean and check spark
electrode
(c) Clean and check photocell
(d) Check overheat safety is
operational
Bi-Annual Inspection
(a) As per quarterly inspection, plus...
(b) Combustion check
(c) Smoke test
Annual Inspection
(a) As per half year inspection,
plus...
(b) Heat exchanger and cleaning
(c) Electrical connections
(d) Main fan motor
(e) Main fan assembly
(f) Pulleys
(g) Fan belts
(h) Oil supply including filter
(i) Burner
(j) Air delivery system
(k) Flue
(l) Report
5.2 Servicing Procedure - Major
Component Parts
Flue
A visual inspection should be carried out to
ensure that the flue remains adequately
supported, both internally as well as externally,
and that the various joints are effectively
sealed.
Inspection covers, where fitted, should be
removed and the flue checked to see whether
cleaning is required
If inspection covers are not fitted the flue gas
exit duct and flue spigot will provide not only
an indication of the cleanliness of the flue, but
will also enable access for cleaning.
The presence of the flue terminal should be
checked.
If a condensate trap and drain facility is fitted
this should be checked to ensure that it
continues to function correctly, and the
drainage of condensates is not impaired.
Main Fan Motor
Remove access panel. Dust and other foreign
matter should be cleaned by blowing over with
compressed air and through the use of a soft
bristle brush and cloth.
Solvent wipes may be used to remove heavy
soiling from the motor casing.
Traces of surplus lubricants spreading from the
bearings should also be cleaned away.
Where motors are fitted with grease nipples
bearings should be lubricated with the correct
grade of lubricant. Motors which do not have
grease nipples feature sealed bearings which
are lubricated during manufacture for their life.
The electrical connections should be checked
as follows.
The cover to the terminal box should be
removed by undoing the screws which secure
it.
Check connections for signs of corrosion,
tightness, and ensure that there are no stray
strands which could form a short circuit.
Clean, tighten, and replace as necessary.
Replace cover and secure.
Main Fan
Remove dust and other foreign matter by
blowing off with compressed air or through the
use of a soft bristle brush.
Check that the bearings do not show signs of
excessive wear.
It should be noted that these bearings do not
require lubricating.
If the bearings require replacing the following
procedure should be followed.
(a) Remove belt(s).
(b) Loosen set screw on eccentric collar and
tap collar in the opposite direction to fan
rotation.
(c) Remove collar and bearing.
(d) Check shaft for alignment and straightness.
(e) Locate the bearing in its seat and place on
the shaft with the cam facing outwards.
(f) Fit the eccentric collar and engage the
cams.
(g) Tighten initially by rotating, and then by
tapping in the direction of the fan rotation.
(h) Replace fasteners and secure.
(i) Turn by hand to ensure free fan rotation.
Pulleys
Check pulleys for alignment using a straight
edge, if necessary reposition either or both of
the pulleys and the fan motor.
Check for excessive wear within the root and
sides of the grooves, and check for any other
signs of wear or damage, if necessary replace
the pulley as follows.
(a) Release tension on belts and remove.
(b) Release the taper locks by slackening the
securing screws by several complete turns.
(c) Fully remove one screw from the taper lock,
and having oiled it, insert into the threaded
jacking point.
(d) Tighten screw until the taperlock is free.
(e) Remove taperlock and pulley.
(f) Fit taperlock in new pulley, and provisionally
position on the shaft.
(g) Remove the screw from the jacking point,
and tighten both screws in their clamping
points until the pulley can just be moved on the
shaft by hand.
(h) Align pulleys using a straight edge, and by
gradual alternate tightening of the screws
clamp in position.
(i) Refit belts and check for the correct amount
of tension.
Fan Belts
Check belts for signs of wear.
Frayed or split belts must be replaced using
belts with a common batch code.
Belt tension must be checked, and if on multibelt units it is found that one belt contains
more slack than its accompanying belts, then
all the belts on the unit must be replaced,
again using a common batch code.
Replacement and tensioning is carried out as
follows.
Note
The maximum displacement at the mid point of
the top edge of the belt must not be greater
than 16mm per metre of span, when a force of
3kg is applied in a plane perpendicular to the
belt.
(a) Loosen fan motor securing bolts on
chassis.
(b) Loosen fan motor slide adjustment bolt.
(c) Slide fan towards fan to slacken belts.
(d) Replace belts, pull fan motor away from fan
until belts are tight.
(e) Tighten adjustment bolt to hold motor.
(f) Tighten fan securing bolts ensuring that the
fan is square and the pulleys aligned.
(g) Check belt tension, making final
adjustments as necessary.
(h) Tighten and clamp fasteners to hold fan
motor in position.
Heat Exchanger
The heat exchanger requires a visual
inspection at least once per year, this should
be accompanied by cleaning. It is
recommended that a flue brush and vacuum
cleaner be used to facilitate this.
Access to the heat exchanger is gained
through the removal of the Front panel and
heat shield.
Servicing and cleaning should be performed as
follows.
(a) Remove brass nuts and cover from heat
exchanger end assembly to expose heat
exchanger tubes.
(b) Remove any accumulated deposits from
the tubes by pushing through the full length
with a flue brush.
(c) The flue brush should be withdrawn so as
to pull any deposits back into the bottom of the
flue box where they can then be removed by
using a vacuum cleaner.
(d) Particular attention should be paid to the
upper internal surfaces of the tubes, where
through convection heavier deposition is likely
to occur.
(e) Any deposits which may have accumulated
within the combustion chamber can be
removed with a vacuum cleaner once the
burner is removed.
Note
It is most important that a build up of deposits
is not allowed to occur as this can have an
adverse effect upon the efficiency of the heater
and reduce the life of the heat exchanger.
(f) The heat exchanger and combustion
chamber should be visually inspected for signs
of splits, cracks, and distortion.
(g) All gaskets should be checked to ensure
that they continue to provide a gas tight seal, if
there is an element of doubt then they should
be replaced.
If the condition of the heat exchanger gives
cause for concern the Service Department
at Benson Heating should be advised
pending a more detailed examination.
Electrical Supply
All connections must be checked to ensure
that they are secure, and free from corrosion.
Terminals and connections should also be
checked to ensure that no stray strands are
bridging terminals.
Electrical continuity should also be checked.
Oil Supply
The oil supply pipe work, tank, and fittings
should all be inspected to ensure that they are
free from corrosion, and to ensure that where
brackets have been fitted these remain secure
and offer adequate support.
The oil filter should be replaced with a new
one, and the system should be checked for
leaks.
If the oil level is such to allow removal of any
sludge or other contaminants form the tank this
too should be undertaken, particularly if there
have been problems of poor firing associated
with contaminants reaching the burner.
Note
Any waste oil or sludge must be disposed
of correctly. Never dispose of it by
dumping or tipping it down drains or into
water courses where ground water can
become polluted and environmental
damage caused.
Burner
Service requirements for the burner fitted to
the heater are covered in the separate manual
prepared by the burner manufacturer.
y
No Power
Check Isolator Check Fuses
Burner
fails to
Run
Burner Lockout
Fan / Limit
Thermostat
No
Demand
Check
Controls
Room
Thermostat
Timer
Heat / Ventilate
Switch
On / Off Switch
Burner
starts
Ignition
sequence
but fails to
light and
Lockout
Occurs
Fuel Feed
Incorrect
Fuel / Air
Problem
No Spark
Check that the
Oil Pressure is
correct
Check Burner
Air Setting
Bleed S
Air in System
Restricted Fuel
Feed
Check
Electrode
Check that Head
of Gravity is
Sufficient
Check that the
suction Lift is not
too great (two
pipe system)
Check that the
Bypass Plug is
Present
stem
Possible Fuel
Contamination
Check Valves,
Fuel Feed, Filter
Nozzle for
Blockages or
Restrictions
Check Control
6.0 Fault Finding
Adjust Air
Damper
Air / Fuel Mix
Ratio Incorrect
Check for Air in
Fuel Line
Burner gives a
sparky flame
Too Much Air
Check Fuel
Pressure
Check Nozzle
Fuel Feed
Restricted
Check Filter
Check Fuel
Lines
Check Valves
Burner
gives a
smokey
flame
Poor
Combustion
Insufficient
Combustion Air
Inadequate Flue
Draught
Check Oil
Pressure
Check Air Damper
Check Nozzles
Check if Correctly
fitted
Check if Correct
size
Check if Damaged
or Worn
Check Flue
g
p
pping
Burner
giving
excessive
noise
Check Burner
Fan Motor
Suction Lift to
Great
Check Burner
O il P um p
Fore ign M atter in
Worn / Dry
Bearing
Insecure Burner
W ate r in F u e l
Line
Fuel Feed
Restriction
Check for High
Resistance
Adjust Warm Air
Warm Air
Short Circuit
Fan and
Limit
regularly
go to
lockout
Discharge and
Cool Air Inlet
Accordingly
Check Outlet
Grilles are not
shut or
Check Filter is
Clear
Check Pulleys
are Secure
Check for no
Loose
Check Belts
and Tension
Insufficient Air
Flow over the
Heat Exchan
er
Check Fan and
Motor
Assembly
Fan and / or
Motor not at
Correct S
eed
Check Fan and
Motor are
Secure
Limit Control
Incorrectly Set
Reset to 100C
Check that Fan
is not Blocked
or Restricted
Check that
Impellor is not
Sli
Wiring Diagram 20-49-146
8.0 MH300 TECHNICAL DATA
Heat Input full load kW 375
Heat output full load kW 300
Nett efficiency full load % 85.4
Gross efficiency full load % 80
Fuel consumption full load L/hr 34.1
Oil pressure full load Psi 150
Running current full load Amps /ph 18
Flue temp full load
0
C 320
Air volume full load M3/s 6
Temperature rise full load
0
C 50
Static pressure full load pa 750
Discharge velocity full load M/s 19.5
Noise level full load Dba @1 m < 90
Heat Input part load kW 225
Heat output part load kW 180
Nett efficiency part load % 90.5
Gross efficiency part load % 84.9
Fuel consumption part load L/hr 26.1
Oil pressure part load Psi 150
Running current part load Amps / ph 18
Flue temp part load
Air volume part load M3/s 2.65
Temperature rise part load
Static pressure part load pa 480
Discharge velocity part load M/s 8.5
0
C 220
0
C 56.6
MH300 TECHNICAL DATA
Duct diameter mm 630
Maximum duct length m 100
Burner type RL28
Burner control HI/Lo
Nozzle specification 3.5/3.0
Oil connection size Bsp 1/4”
Fuel specification 35 sec
Head setting 5
Air shutter Hi / Lo 70 / 28
Electrical supply V/Hz/Ph 415/50/3
Fuse Size Amps 6
Maximum running current Amps 16
Flue diameter mm 225
Overheat thermostat setting
0
C 100
IP Rating 44
Weight kg 1200
Height mm 2350
Width mm 1180
Length mm 3600
9.0 Reference Information
Doc/Ref Title/Subject
BS 5410 Part 1 ; 1977 and Part 2 ; 1978 Code of Practice for oil firing
BS EN 292 Parts 1 and 2; 1992 Safety of Machinery
BS EN 60204 Part 1; 1993 Safety of Machinery - Electrical
BS EN 60335 Part 1; 1988 Safety of Electrical Appliances
BS EN 55014 1993 Electromagnetic Compatibility
BS EN 50165 1995 Safety of Electrical Equipment
BS 5854 1980 Code of Practice - Flues/Flue Structures
BS 799 Part 5 ; 1987 Oil Burning Equipment - oil tanks
OFTEC OFS T-100 Polyethylene oil storage tanks
BS 715 1993 Metal Flue Pipes and Fittings
BS 5440 Part 1 ; 1990 Specification/Installation of Flues
BS 5440 Part 2 ; 1989 Ventilation Requirements Gas Appliances
BS 779 Part 2 ; 1991 Oil burning equipment - burners
ISO 228/1 See also BS 2779 and BS 5380) Pipe Threads Seals and Couplings
Benson Heating.
Ludlow Road
Knighton
Powys
LD7 1LP
Telephone 44 (0)1547 528534
Facsimile 44 (0)1547 520399
Email information@bensonheating.co.uk
www.bensonheating.com
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