Enertech Nu-Way NG Series Instruction Manual

Installation & Maintenance Manual
Series NG fully automatic gas burner
Models NGN40 to NGN100
Gas Burner
11/12
Tel:[phone] Fax: [phone] Email: [email protected] Web: www.nu-way.co.uk

Model NGN40-100Page 2
Contents
BURNER & COMPONENT I DENTIFICATION ............................................................................................................ 4
FEATURES ........................................................................................................................................................... 6
Burner Capacity .............................................................................................................................................................................. 6
Air Regulation ................................................................................................................................................................................. 6
Controls .......................................................................................................................................................................................... 6
Operation ........................................................................................................................................................................................ 6
Fuel ................................................................................................................................................................................................. 6
GENERAL ........................................................................................................................................................... 6
Flue And Chimney Requirements.................................................................................................................................................... 6
Plant Room Ventilation .................................................................................................................................................................... 6
Existing Appliances......................................................................................................................................................................... 6
Com ustion Cham er Conditions ................................................................................................................................................... 7
PACKAGING FOR TRANSIT ................................................................................................................................. 7
Mode One: Comprising Two Units ................................................................................................................................................. 7
Mode Two: Comprising Three Units ............................................................................................................................................... 7
Assem ly ........................................................................................................................................................................................ 7
SERVICES & SITE CONDITIONS ........................................................................................................................... 7
Gas Supply ...................................................................................................................................................................................... 7
Gas Boosters ................................................................................................................................................................................... 7
INSTALLATION .................................................................................................................................................... 8
General ............................................................................................................................................................................................ 8
Fitting To The Appliance ................................................................................................................................................................ 8
Electrical Power Supply................................................................................................................................................................... 8
BURNER AIR CONTROLS .................................................................................................................................... 8
Air Diffuser ..................................................................................................................................................................................... 8
Air Pressure Switch......................................................................................................................................................................... 8
BURNER GAS CONTROLS ................................................................................................................................... 8
Gas Nozzle ....................................................................................................................................................................................... 8
High Gas Pressure Switch ............................................................................................................................................................... 8
Low Gas Pressure Switch ................................................................................................................................................................ 8
Gas Valve Train ............................................................................................................................................................................... 8
ELECTRICAL DATA TABLE ................................................................................................................................... 9
TERMINAL CONNECTIONS - HIGH/LOW BURNER ................................................................................................ 9
TERMINAL CONNECTIONS - MODULATING BURNER ........................................................................................... 10
WIELAND PLUG & SOCKET CONNECTIONS ....................................................................................................... 11
Air/Gas Ratio Controller .................................................................................................................................................................12
Valve Proving Systems ..................................................................................................................................................................12
Landis & Staefa LDU11 .................................................................................................................................................................. 12
Dungs VPS 504 ..............................................................................................................................................................................12
CONTROLS ...................................................................................................................................................... 12
FLAME MONITOR ............................................................................................................................................ 12
GAS VALVE TRAIN - LANDIS & STAEFA SKP70 / SKP10 ................................................................................. 13
LANDIS & STAEFA SKP70 VALVE A CTUATOR ................................................................................................... 14
AIR DAMPER MOTORS - H/L ..........................................................................................................................14
CONTROL BOX SEQUENCE AND TIMING CHART ................................................................................................ 1
AIR DAMPER MOTOR - MODULATING ............................................................................................................. 1
MODULATING OPERATION ................................................................................................................................16
Burner Control Panel. ..................................................................................................................................................................... 16
Manual Operation ..........................................................................................................................................................................16
Temperature detector......................................................................................................................................................................16
Pressure detector. ...........................................................................................................................................................................16
Gas controls. ..................................................................................................................................................................................16
SKP70 com ustion cham er impulse connection. .........................................................................................................................16
Installation of the com ustion cham er impulse pipe. ...................................................................................................................17
IMPORTANT - SAFETY ............................................................................................................................ 17
EMERGENCY INSTRUCTIONS .............................................................................................................. 17
BURNER OPERATING SEQUENCE ........................................................................................................................ 17
Initial Burner Setting ...................................................................................................................................................................... 17
Air/Gas Ratio Controller .................................................................................................................................................................17
Start Rate Gas Governor ................................................................................................................................................................. 17

Page 3
Model NGN40-100
IMPORTANT - SAFETY
It is essential that the following instructions and adjustments are carried out by qualified engineers that
are experienced in blown gas burner commissioning. In the U.K. it is a legal requirement that anyone
working on gas installation, as defined in the  as Safety (Installation & Use) Regulations 1994 is
COR I registered. The manufacturer cannot be held responsible for any consequential damage, loss or
personal injury as a result of failure to follow these instructions, or as a result of misuse. Your attention
is drawn to the Emergency Instructions on Page 17.
EUROPEAN BOILER EFFICIENCY DIRECTIVE (B.E.D.)
All burners and boiler bodies marketed seperately should comply with EN676 (gas burners) and EN303
(Heating Boilers). Burner adjustments must be made in accordance with boiler manufacturers
instructions, and these must include flue gas temperatures, average water temperature, and CO2 or O2
concentration.
BURNER PRE-COMMISSIONING ......................................................................................................................... 17
BURNER COMMISSIONING ................................................................................................................................18
Check For Valve Closure (Burners Without Valve Proving System) ..............................................................................................18
Gas Supply Pressure ......................................................................................................................................................................18
ESTABLISHING MAIN FLAME ............................................................................................................................ 18
General Notes.................................................................................................................................................................................18
Landis & Staefa SKP70 ..................................................................................................................................................................19
BURNER START G AS RATE ................................................................................................................................19
Check Flame Signal ........................................................................................................................................................................19
Air Pressure Switch Setting ...........................................................................................................................................................20
High Gas Pressure Switch Setting ..................................................................................................................................................20
Low Gas Pressure Switch Setting ...................................................................................................................................................20
FINAL CHECK .................................................................................................................................................. 20
RWF40 MODULATING CONTROL .................................................................................................................... 20
Basic display ..................................................................................................................................................................................20
To change the working set point....................................................................................................................................................20
To enter a new parameter ...............................................................................................................................................................21
ROUTINE SAFETY CHECKS ................................................................................................................................22
Com ustion Air ..............................................................................................................................................................................22
Flame Detector ...............................................................................................................................................................................22
Valve Proving System ....................................................................................................................................................................22
ROUTINE MAINTENANCE .................................................................................................................................. 22
Com ustion Air Fan .......................................................................................................................................................................22
Inner Assem ly ..............................................................................................................................................................................22
Air Diffuser And Gas Nozzle ..........................................................................................................................................................22
Ignition Electrode...........................................................................................................................................................................22
FAULT F INDING ................................................................................................................................................ 22
Burner Motor Fails To Start ...........................................................................................................................................................22
Starting Flame Failure Without Ignition .........................................................................................................................................23
Starting Flame Failure Without Flame ............................................................................................................................................23
Burner Fails To Esta lish Main Flame ............................................................................................................................................23
Burner Motor Only Runs Continuously ........................................................................................................................................23
Replacement Of Air/Gas Ratio Controller .......................................................................................................................................23
Incorrect Rotation Of Burner Motor ..............................................................................................................................................23
Motor & Fan - Removal .................................................................................................................................................................23
SERVICE & REPLACEMENT ............................................................................................................................... 23
BURNER HEAD DETAILS .................................................................................................................................... 24
BURNER PERFORMANCE CURVES ...................................................................................................................... 2
BURNER SERVICE RECORD .............................................................................................................................. 31

Model NGN40-100Page 4
BURNER & COMPONENT IDENTIFICATION
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Page 5
Model NGN40-100
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Model NGN40-100Page 6
GENERAL
The N 40-N 100 burner is supplied for two stage
(High/Low) or fully modulating operation and for
use with a three phase electrical supply.
This manual is structured to enable the user to
proceed from the delivery of the burner to its
commissioning and use.
The conditions to be fulfilled and the controls and
adjustments to be used are dealt with in the
sequence that should be followed for the correct
assembly installation and use. Pre-commissioning
and commissioning are described and the location
of necessary controls and adjustments to
undertake these runs are illustrated and supported
by appropriate tabular matter and graphs.
Routine Maintenance, Fault Finding and Spare Parts
Identification complete the manual; literature on
proprietary components is available on request.
Flue And Chimney Requirements
It is important that:
a) the flue pipe from the appliance and the joint
between this flue and the chimney are sealed
to prevent leakage of combustion products.
b) the flue pipe from the appliance does not
protrude into the chimney beyond the inside
wall.
c) the top of the flue or chimney shall be higher
than any roof within a radius of 10 metres.
d) checks are made to ensure that the chimney
is suitable for gas fired appliances and that
the proposed installation complies with all
Local Authority and other regulations
covering such installations.
e) if more than one appliance is connected to
a common flue or chimney the cross-section
of this flue or chimney should be adequate
for the total volume of combustion products
from the appliances.
Plant Room Ventilation
An adequate dust free supply of fresh air is required
for the burner at both high and low level in
accordance with the appropriate standards.
Existing Appliances
In preparing the appliance to receive the N gas
burner a careful inspection should be made of its
condition. If in doubt as to its suitability for gas
firing refer to the appliance manufacturer.
FEATURES
Burner Capacity
Developed from field experiences in the UK and
overseas markets, the N series sets new standards
in efficient and reliable operation, having been
developed to current test authority requirements
in UK and overseas markets. It is delivered ready
to install with pre-wired packaged control system
and simple plug in gas train arrangements.
Air Regulation
Air for combustion can be adjusted to give
maximum efficiency. A air control device produces
smooth start conditions. A fully closing air control
is fitted as standard.
Controls
Flame supervision is by UV cell, and automatic
sequence control.
Operation
Two stage (high/low) and fully modulating
operation.
Fuel
Natural as. Special requirements on request - i.e.
Liquid Petroleum as / Town as.
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58NGN 0980142941
001NGN 05320503891

Page 7
Model NGN40-100
In preparing the appliance for gas firing it should
be cleaned thoroughly removing all adhering tars,
scale and dirt.
Com ustion Cham er Conditions
When the burner is fitted to an appliance designed
to work under balanced or negative combustion
chamber conditions, the over-fire draught must not
exceed 0.25 mBar.
Should the over-fire draught exceed this figure, then
steps should be taken to reduce it to this level.
PACKAGING FOR TRANSIT
To safeguard against transit damage and for Export
shipment, the burner may be despatched in partly
assembled form in one of two modes.
Mode One: Comprising Two Units
a) Burner Body, complete with Control Package,
Hinged Extension and Flame Tube Assembly.
b) as train complete.
Mode Two: Comprising Three Units
a) Burner Body complete with Control Package.
b) as Train Complete.
c) Hinged Extension and Flame Tube Assembly.
Assem ly
Mode One
Fit the gas valve train to the burner body using the
gasket provided. Ensure that the gasket is fitted
correctly with all holes corresponding with those
on the burner flange. Connect the combustion air
impulse pipe from SKP70 gas valve to left hand
side of the hinged extension.
Mode Two
Fit the hinged extension and flame tube assembly
to the burner body with the eight studs provided.
Ensure the gas inlet flange is at the bottom. Fit the
gas valve train to the burner body, with the four
studs and using the gasket provided. Ensure that
the gasket is fitted correctly with all holes
corresponding with those on the burner flange.
Connect the combustion air impulse pipe from
SKP70 gas valve to left hand side of the hinged
extension.
Modes One & Two
Open the hinged extension and connect the
Ignition cable to the electrode. Close hinged
extension.
Connect the multi-pin plug from the gas valve train
to the socket located on the rear of the control
package on the left of the burner body.
SERVICES & SITE CONDITIONS
Gas Supply
The gas supply pipework to the burner must be
appropriate to local conditions and must be
constructed and installed in compliance with
appropriate Codes and Standards. It shall be of
sufficient size to satisfy the pressure and volume
flow requirements of the burner under all firing
conditions. Checks should be made to ensure that
all meters and other components are appropriately
rated for the maximum gas flow rate anticipated.
It is essential that a 90° manual isolation valve is
fitted upstream of the gas control train to allow
the burner to be isolated for maintenance The size
of this valve should not be less than that of the
burner control train in order to avoid any restriction
in gas flow
Gas Boosters
When a gas booster is used the gas pressure at the
booster inlet must not fall below 10 mbar under
any conditions. A low gas pressure switch must be
fitted on the upstream side of the booster to
prevent it starting if the supply pressure is
insufficient. An additional pressure switch can be
used to monitor the pressure downstream of the
booster to prevent the burner operating if the
pressure is insufficient.
The booster should be installed as near to the
burner as possible. It should be positioned on a
firm, flat, horizontal surface using anti-vibration
mountings. All connecting pipework should be well
supported and accurately positioned in order to
avoid stressing the booster casing. The use of
flexible connectors, which reduce both pipework
stresses and transmitted noise, is strongly
recommended. The gas supplier should be asked
to recommend the size of pipework between the
meter and the booster to ensure that the required
pressure and flow are available.

Model NGN40-100Page 8
INSTALLATION
General
Check that the burner is appropriate for appliance
rating. Detailed burner performance data is given
at the back of this handbook.
Fitting To The Appliance
If the burner is to be fitted to a new packaged unit,
refer to the manufacturers recommendations.
If the burner is to be used with an existing
appliance prepare the mounting flange as detailed
in the Burner And Components Identification
section. Ensure the joint between appliance and
burner is effectively sealed with the gasket
provided. The flame tube should be flush with the
inner face of the appliance combustion chamber
except where extensions are specified by the
appliance manufacturer (i.e. reverse flame boilers).
Electrical Power Supply
Connect a three phase 50 Hz electrical supply to
the burner observing all applicable IEE Regulations.
Refer to the connection diagrams on pages 9-11
or the wiring diagram contained in the instruction
pack attached to the burners. If supplied as a
packaged appliance/burner unit refer to the
manufacturers instructions.
Connect the external auxiliary controls by
reference to the appropriate connection/wiring
diagram.
BURNER AIR CONTROLS
The air for combustion is controlled by an
adjustable air flap located inside the air inlet on
the right hand side of the burner viewed from the
rear. Its purpose is to regulate and control the
volume of combustion air flowing through the
burner. Combustion air is controlled by a three
position servo motor. Positions for high and low
flame air are adjustable. A fully closed position is
incorporated for when the appliance temperature/
pressure is satisfied.
Air Diffuser
The air diffuser is fitted to the front end of the inner
assembly and located within the flame tube.
Its function is to control the volume of combustion
air and create a pressure drop over the burner head
to ensure good fuel/air mixing and flame stability.
Air Pressure Switch
The air pressure switch is located on the right side
of the burner casing viewed from the rear. It is
required to prove adequate air flow throughout
the burner operating cycle. Air flow failure at any
stage will result in burner lockout.
BURNER GAS CONTROLS
Gas Nozzle
The gas nozzle is fitted to the front end of the inner
assembly and located in the flame tube. The holes
in the gas nozzle are designed to suit the output of
the particular burner model and gas type being
used.
High Gas Pressure Switch
A high gas pressure switch is fitted and pre-wired
to the gas train to ensure that if the gas pressure at
the burner head increases above the gas pressure
at maximum continuous running, then the burner
will shut down to a safe condition, thus indicating
a fault on the governing valve (air/gas ratio valve).
The switch is factory set to the maximum position.
Final adjustment of this switch is described in the
Commissioning section on page 20.
Low Gas Pressure Switch
The low gas pressure switch is located on the inlet
side of the gas valve block on the left of the burner,
viewed from the rear. It is required to monitor inlet
gas pressure during the burner operating cycle. as
pressure failure will result in safe shutdown of the
burner. Final adjustment of this switch is described
in the Commissioning section on page 20.
Gas Valve Train
The gas valve train system includes an air/gas ratio
controller, safety shut-off valve, and gas regulator
in the start rate line. Three impulse pipes are
connected to the air/gas ratio controller. All are
factory supplied. One pipe is connected to the
burner hinged extension and supplies combustion
air pressure to the ratio controller. A second pipe
is connected downstream of the valve set and
supplies gas pressure to the ratio controller. The
third pipe is vented to atmosphere. Valve
adjustments are detailed in Valve Adjustment
Diagram on page 14.

Page 9
Model NGN40-100
TERMINAL CONNECTIONS - HIGH/LOW BURNER
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ELECTRICAL DATA TABLE
L*=(If fitted) for connection of independent
control circuit supply If not required fit 0 75mm
(24/ 20) link between L1 & L
BR=Burner run
LO=Lockout
NB: For details of booster connections, refer to
the instruction pack provided with the booster
Wiring diagram for connection of burner to power supply for
NG40-100 with DOL fan motor starter

Model NGN40-100Page 10
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TERMINAL CONNECTIONS - MODULATING BURNER

Page 11
Model NGN40-100
WIELAND PLUG & SOCKET CONNECTIONS
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harness and wire to terminals as shown on pages 9 & 10.
High/Low burners = 7 & 4 pin sockets.
Modulating burners = 7 & 6 pin sockets.

Model NGN40-100Page 12
Air/Gas Ratio Controller
The air/gas ratio controller varies the gas pressure
in response to changes in combustion air pressure
to ensure that the air/gas ratio remains constant
over the operating range of the burner. A separate
gas pressure governor is not necessary. Three
impulse pipes (all factory supplied) are connected
to the air/gas ratio controller. The first is connected
to the burner body and supplies air pressure to
the ratio controller. Note that in installations with
negative air pressure in the combustion chamber,
this pipe must always be under positive pressure.
A second pipe connected to the gas line
downstream of the valve set provides gas pressure
to the ratio controller whilst the third pipe is vented
to atmosphere.
Valve Proving Systems
A valve proving system, as shown schematically
below, is standard on all burners with outputs
greater than 1200kW (net) or 1325 kW (gross).
Landis & Staefa LDU11
When the burner operating sequence is initiated,
the burner control box energises the proving
system, which then carries out the following checks.
a) Valves V1, V2 and V3 are initially closed. The
proving system then opens V3 (in the start
gas line) and then closes it after 2 seconds.
b) V1, V2 and V3 remain closed for 23 seconds
while the minimum side of the gas pressure
switch (PS) checks for an increase in pressure.
If no increase occurs there is no leakage past
V1 and the sequence continues.
c) V1 is opened for 2 seconds and then closed.
V1, V2 and V3 again remain closed for 23
seconds while the maximum side of the gas
pressure switch checks for a decrease in
pressure. If no decrease occurs there is no
leakage past V2 or V3 and the burner
operating sequence will continue.
Dungs VPS 504
The VPS 504 is a self contained unit that operates
on the pressure build up principle.
The programmer starts functioning when the burner
control circuit is made. With valves V1, V2, & V3
in the closed position, the internal pump increases
the gas pressure within the test section
approximately 20 mbar above the pressure at the
inlet to V1. During this time an integral differential
pressure switch monitors the test section for leaks.
When the test pressure is reached, the pump is
switched off. If the proving check has been successful
(max 30 secs), the control circuit is released
accompanied by illumination of the yellow
indicator light on the unit.
If the proving check has been unsuccessful or if a
pressure rise of +20 mbar has not been reached
during the test time (max 26 secs), the unit will
switch to the fault condition accompanied by
illumination of the red indicator light. This
condition will remain until the unit is manually
reset or the control circuit is broken.
If there is a short power failure during test or burner
operation, reset is automatic.
CONTROLS
The control package is fitted on the left hand side
of the burner viewed from the rear. It includes a
sequence control box of the cyclic type, ignition
transformer and all necessary contactors, terminal
strip, motor starter, On/Off switch and two neon
lights. The amber light indicates BURNER ON
and the red light is illuminated when the burner
stops as a result of EXCESS TEMPERATURE in
the appliance.
FLAME MONITOR
An ultraviolet cell is fitted as standard on all
burners.

Page 13
Model NGN40-100
Typical Gas Valve A angement with Landis & Gy Cont ol Valves
GAS VALVE TRAIN - LANDIS & STAEFA SKP70 / SKP 0
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Model NGN40-100Page 14
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ci cumstances should not equi e fu the adjustment.
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by manually adjustable cams. A setting scale is p ovided
at the end of the cam stack fo guidance, while adjustments
a e made using the sc ew adjuste s situated within the
cam disk body (STM30 Q5), o with leve s and fine setting
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Page 15
Model NGN40-100
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The fully closed cam (2) is facto y set and unde no mal
ci cumstances should not equi e fu the adjustment.
Ope ation of the low and high flame ai switches (cams
3&1) is made by manually adjustable cams. Setting scales
p ovided between the cams simplify the adjustment. An
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position indicato .
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Model NGN40-100Page 16
MODULATING OPERATION
Nu-way N modulating burners are similar in
construction and operation to the 2 stage High/
Low versions, utilising identical fan blower,
combustion head and gas train components.
The standard method of operation is based on the
Landis & Staefa RWF40 Universal Controller, which
provides temperature or pressure control of
modulating burners with continuously adjustable
fuel throughput.
The control output of the RWF40 is a potential
free, 3-position switch, which is used to control
the air damper motor.
When the boiler control calls for heat, the modulating
servomotor will travel to the high flame position and
interlock the control circuit. An air pre-purge will take
place at this position for a pre-determined period, at
the end of which the burner sequence controller will
stop until the modulating servo has travelled to the
low flame position and interlocked the control circuit
again. The sequence control will now recommence
its operational cycle and the burner will light and
remain at low flame until the high flame release signal
is given by the sequence control. The modulating
servo will now move to high flame and remain at this
position until the desired boiler temperature/pressure
is attained. From this stage the modulating unit will
commence to move towards the low flame position,
but, depending on the temperature/pressure, will stop
in any intermediate position between low and high
flame.
Burner Control Panel.
The control panel is fitted to the rear left hand side
of the burner fan casing. The panel is of the fully
enclosed type containing the fan motor starter,
relays, burner sequence control, RWF40
modulating controller. Access to the panel is
gained by loosening the two crosshead screws on
the right hand edge of the panel door. The door
may then be swung open to the left and removed
from its hinge pins if required.
Manual Operation
Check that the RWF40 controller is configured
correctly (refer to page 21). Press and hold the EXIT
key until the manual operation indicator
illuminates. The modulating motor can now be
inched using the increase & reduce buttons on
the controller face. Press and hold the EXIT key
until the manual operation indicator extinguishes
to return to automatic mode.
Temperature detector.
The immersion temperature detector type QAE22
is used in all Hot Water boiler applications. The
detector has a plastic casing to IP42 with a snap
on cover and an immersion stem. The connection
terminals can be accessed by removing the cover.
Cable entry is made via a cable entry gland Pg11.
In all applications an immersion pocket with a flat
seal is supplied.
The detector should be installed in an elbow such
that the pocket points against the direction of flow.
With all detector versions, the immersion length
must be a minimum of 60mm.
Pressure detector.
The Pressure sensor type QBE620 is used in all
Steam boiler applications. The sensor has an
aluminium casing to IP65 and a 2 metre long, 3
core connecting cable. The mounting instructions
supplied with the sensor are to be strictly adhered
to.
Gas controls.
The gas train is of the same type and design as fitted
to 2 stage high/low models.
SKP70 com ustion cham er impulse
connection.
The impulse connection to the combustion
chamber is not required in the majority of
applications and is therefore not supplied as part
of the burner package. This is because the
resistance of the combustion chamber / flue
assembly is assumed to remain constant and that
the pressure within this chamber will change in
proportion to the burner gas and combustion air
pressure. (As the burner output changes).
If, however, the pressure in the combustion
chamber does not change in proportion to the
burner gas or air pressure, i.e. the plant is fitted
with a flue gas fan, continuously operating flue gas
damper, or the chamber pressure changes from
negative to positive whilst moving from Low to High
flame, then a compensating circuit is required. This
means that the pressure in the combustion
chamber must be connected to the SKP70 so that
the controller can automatically offset the pressure
changes.
This compensating circuit should also be used if
pressure shocks and vibrations, which adversely
affect burner start up, develop in the combustion
chamber during the start up phase.

Page 17
Model NGN40-100
Naturally, it must always be taken into
consideration that the burner output decreases as
the pressure in the combustion chamber increases,
and visa versa.
Installation of the com ustion cham er
impulse pipe.
A minimum inside pipe diameter of 8mm is
recommended.
The impulse pipe should be as short as possible
so as to allow the controller to respond quickly to
sudden burner output changes. It must be installed
such that the gases will cool down in the area of
the impulse pipe and condensing gases will not
enter the controller but run back into the
combustion chamber. If necessary, a water
separator must be provided.
IMPORTANT - SAFETY
It is essential that the following instructions
and adjustments are carried out y qualified
engineers that are experienced in lown
gas urner commissioning. In the U.K. it is
a legal requirement that these engineers
should also e CORGI registered. The
manufacturer cannot e held responsi le
for any consequential damage, loss or
personal injury as a result of customers
failing to follow these instructions, or as a
result of misuse.
EMERGENCY INSTRUCTIONS
This product has een designed and
constructed to meet all of the essential
requirements of the GAS APPLIANCE
DIRECTIVE 90/396/EEC and under normal
circumstances should not give occasion to
any hazardous conditions. If such a
condition should occur during
commissioning or su sequent use of this
product, e it a fault of the urner, the
appliance or of any instrument, machine
or service in the proximity of the urner,
then the GAS and ELECTRICITY supply to
the urner should e IMMEDIATELY
ISOLATED until such time that the fault has
een investigated and rectified.
BURNER OPERATING SEQUENCE
The operating sequence begins with an air pre-
purge on full air, followed by start rate gas flame
which when proved allows the burner to operate
on the High/Low/Off or Modulating principal. The
sequence is determined by the demand of the
appliance control instruments.
Initial Burner Setting
Remove the cover from the air damper motor on
the end of the air inlet casing. Check the cam
positions and adjust if necessary (refer to settings
on pages 14 & 15).
Air/Gas Ratio Controller
Remove the small plate on top of the regulator and
keep it in a safe place. Set the air/gas ratio at 0.8
on the visual scale by adjusting the screw (1)
anticlockwise to increase, or clockwise to decrease.
Set the air/gas ratio on the visual scale, adjusting
screw (2) to half a division on the + side of 0.
Turn the adjusting screw clockwise to decrease, or
anticlockwise to increase.
Start Rate Gas Governor
Remove the metal cap from the top and turn the
adjusting screw until it is approximately halfway
between maximum and minimum setting,
clockwise to increase, and anticlockwise to
decrease. Never adjust to its maximum limit.
BURNER PRE-COMMISSIONING
Check both gas and electricity supplies to the burner
are turned off. Remove the cover and fit a link
between terminals 2 & 3 of the low gas pressure
switch. Remove the control panel cover and remove
the low flame hold link (two stage burners). Set the
air pressure switch to minimum. Replace the control
panel cover. Momentarily switch on the burner and
check the motor rotation, which should be
anticlockwise, viewed from the motor end.
If the direction of rotation is incorrect, please refer
to Fault Finding to correct it. Switch on the burner.
Depending on the type of the control box, the
burner will go through its operating sequence
a) Immediately if it has previously been working
but switched off during a normal operating cycle.
b) On pressing the reset button on the control box.
The burner motor will run. If at this stage the burner
goes to lockout, please refer the Fault Finding
section (page 22)

Model NGN40-100Page 18
Check that the ignition spark is present. For actual
timings refer to the Sequence Diagram and Timing
Chart on page 15.
If at this stage there is no ignition spark and the
burner goes to lockout, the air pressure switch may
require adjustment. Following the safety lockout
time (T3) the ignition spark should cease and the
burner go to lockout.
Switch off the electrical supply to the Burner.
Remove the Control Panel cover and refit the Low
Flame Hold link. Replace the Control Panel cover.
Remove the temporary link between terminals 2
& 3 of the Low as pressure switch and refit and
secure the cover.
Safety system proved. Burner commissioning can
proceed. Switch off power to the burner.
BURNER COMMISSIONING
Check that the appliance is in a proper and safe
state to be fired (for instance, is there water in the
boiler?)
Set the appliance controls to call for heat.
Check For Valve Closure (Burners Without
Valve Proving System)
All gas train assemblies are fully tested for function
and valve security before despatch.
A soundness test of the gas valves is difficult
without specialised pressure testing equipment.
However, the following check can be performed
to measure the security of the valve system.
Ensure that the gas supply pipework to the burner
gas line inlet is sound and that gas is available at
the required inlet pressure for the burner. Fit a
manometer to the test point at the inlet to the
upstream main safety valve. Open the main
upstream manual valve for a few seconds and then
close and secure the gas supply.
The space between the upstream manual valve
and the gas train inlet should now be filled with
gas at inlet pressure. If the pressure remains stable
over one minute then this indicates that the valve
train is secure, but not necessarily in the main valve.
If the pressure decreases then this indicates that
the main and one other valve is leaking or that
there is a leak between the upstream manual valve
and the main gas valve.
Secure the upstream test point and fit the
manometer to the test point situated between the
main and control valves.
Check the reading on the manometer, this should
now show near atmospheric pressure. Open the
upstream manual valve and look for an increase
in pressure over one minute. If no rise is detected,
this indicates that the main valve is closing correctly.
The next stage of the procedure requires the burner
to be momentarily started. Open the upstream
manual valve and switch the burner on. The burner
will attempt to start and will either establish a
flame (in which case switch the burner off
immediately) or 'lockout'. Isolate the electricity
supply.
The space between the main and control valves
should now be filled with gas at near inlet pressure.
If the pressure remains stable over a period of one
minute, this indicates that the valve system is
secure.
If the pressure decreases, this indicates that there
is a leak in the valve system and the valve train
assembly should be returned to the factory for a
full examination. Remove the manometer and
close the test point.
Gas Supply Pressure
The main gas safety valve is capable of withstanding
gas inlet pressures up to 200 mbar. For N 40 and
N 100 burners it is essential that the inlet gas
pressure shall not be less than 45 mbar and not
be more than 100 mbar in order to maintain good
control characteristics of the air/gas ratio controller.
Before proceeding with commissioning:
a) Fit a manometer or other approved pressure
measuring instrument to the pressure test
point on the upstream side of the first safety
shut-off valve.
b) Open the manual gas isolation valve at the
inlet to the gas train.
c) Check that the gas pressure is adequate.
ESTABLISHING MAIN FLAME
General Notes
In the following sections, reference is made to
checking gas flow rates at the gas meter. This is the
most accurate method of determining throughputs
and should always be used whenever possible.
Information regarding the burner head gas pressures
is included in the appendix at the back of this
manual. These may be used as a guide to initial
burner settings, but should not be relied upon to
offer proof of actual throughputs.

Page 19
Model NGN40-100
IMPO TANT After each adjustment, gas flow rate
and flue gas analysis should be checked.
ALWAYS use approved test equipment.
NEVE rely on a visual inspection of the flame as a
guide to combustion quality.
Landis & Staefa SKP70
Refer to the Valve Adjustment Diagram on page
14. Set up the air damper for initial firing as follows.
Low flame air 15 °: High flame air 60°. Close the
upstream manual valve until it reaches an opening
of approximately 20%.
Set the gas inlet pressure switch to minimum.
Remove the low flame check link. Switch the
burner on and allow it to establish low flame.
radually open the upstream manual valve to the
fully open position keeping a watchful eye on the
CO level.
If the CO content is excessive, adjust the low fire
adjustment screw (2) on the SKP70 valve to achieve
acceptable figures. In extreme cases it is possible
to run out of adjustment on the low fire screw
without achieving the desired results. If this
happens adjust the High Fire setting screw (1) to
bring the CO content down to an acceptable level.
Switch the burner off and refit the low flame link.
Restart the burner. Low flame will be established,
expanding to main flame after the expiry of period
T6 on the control box timing chart.
It is important to monitor the flame visually during
the change from low to high. If the flame becomes
more compact, this indicates an excess of
combustion air. If the flame becomes large and
shapeless, this indicates an excess of fuel. Both
conditions are acceptable at this stage providing
that the burner remains stable and immediate
actions are taken to correct the situation. If in
doubt SWITCH OFF the burner and adjust the
High Flame screw (1) on the SKP70 in the
appropriate direction.
With the burner stable on high flame, adjust the
High Flame screw (1) to bring the CO2 to an
acceptable level. It is possible at this stage that the
burner may be overfiring the appliance with a
resultant excess of CO.
With the burner firing at low flame, adjust the Low
Flame screw (2) on the SKP70 valve to bring the
CO2 content within an acceptable range.
Adjustment of the Low Flame setting will have
marginal effect on High Flame. To achieve optimal
results repeat the above procedures on High and
Low flame several times until acceptable figures
are obtained without any further adjustment.
It should not be necessary to make any further
adjustments to the gas valve.
With the burner now running on high flame, the
gas throughput should be checked at the gas meter.
Ensure that any other appliances served by the
meter are isolated during the checks. The gas rate
can be altered by adjusting the air damper opening
in the appropriate direction. Similarly the low flame
throughput can be adjusted by altering the low
flame position of the air damper. Care should be
taken so as not to exceed the limits of the burner
performance envelope as shown on pages 25-29.
With the gas flow rate set for both Low & High flame
a final check should be made on the flue gases. For
reasons of safety, the CO (carbon monoxide) level
should be checked and should not exceed a
maximum of 93 ppm (dry air free).
BURNER START GAS RATE
Switch off the electrical supply to the burner, close
the main manual gas valve, remove the control
panel cover, disconnect the pilot check link, and
replace control panel cover.
Switch on the electrical supply to the burner and
allow the burner to establish start rate flame.
The start gas rate can now be adjusted by turning
the adjusting screw in the start gas pressure
governor clockwise to increase and anticlockwise
to decrease. A start rate of approximately 30% and
not more than a maximum of 33% of main flame
is required.
Too small a start gas rate results in burner lockout
on changeover during the initial and final running.
Never exceed the stated percentage start gas rate.
Switch off the electrical supply, remove the control
panel cover, reconnect the pilot check link, replace
the control panel cover. Open the main manual
gas valve.
Switch on the electrical supply to the burner.
Check Flame Signal
Switch off the burner. Remove the control panel
cover and disconnect the flame signal check link.
Connect a DC. microammeter, range as shown in
the wiring diagram section in this manual.

Model NGN40-100Page 20
Refer only to the wiring diagram appropriate to the
control fitted on the burner.
Switch on the burner and observe on the micro-
ammeter the flame response signal. A steady
reading in excess of 7µA indicates the burner is in
a reliable run situation.
If the current recorded is too low, it may be due to
some maladjustment of the flame and intermittent
lockout may occur. Check and reset if necessary.
Refer to the Fault Finding section. Switch off the
burner and disconnect the microammeter. Refit the
link and control panel cover.
Air Pressure Switch Setting
Switch off the electrical supply to the burner.
Remove the air pressure switch cover. Fit a
manometer to the pressure switch to check the
actual air pressure against the pressure switch dial
setting.
Remove the control panel cover and disconnect
the low flame hold link to hold the burner in the
low flame position.
Switch on the electrical supply and allow the
burners to establish main flame.
Slowly turn the adjusting dial clockwise until the
flame is extinguished. The burner will go to lockout.
Turn the dial one division anticlockwise and reset
burner lockout. The burner will then continue
through its cycle until either the start rate flame is
established or the burner goes to its lockout
position. If the burner goes to lockout repeat the
procedure once per burner cycle until the start rate
flame is established. Allow the burner to cycle to
low flame and then turn the adjusting dial a further
two divisions anticlockwise.
Switch off the electrical supply to the burner,
reconnect the low flame hold link, replace the
control panel cover and also the air pressure switch
cover, and remove the manometer.
High Gas Pressure Switch Setting
When the burner is finally commissioned, the gas
switch must be adjusted with the burner running.
Remove the cover, and move the dial in an
anticlockwise direction until the switch trips and
the pressure switch indicating light is illuminated
(the burner will shut down). Move the pressure
switch dial in a clockwise direction one division,
fit the cover, and reset the pressure switch via the
button situated on the pressure switch cover. The
burner will now restart.
Low Gas Pressure Switch Setting
The low gas pressure switch is wired in series with
the appliance controlling instruments and will
cause the burner to effect a safety shut down if a
loss of inlet gas pressure is detected.
Isolate the burner and remove the gas pressure
switch cover. Switch on the electrical supply and
allow the burner to establish main flame. Slowly
turn the adjustment dial on the gas pressure switch
clockwise until the flame is extinguished and the
burner shuts down. Turn the dial slowly
anticlockwise one division at a time until the
burner restarts and establishes main flame.
Recheck the performance and then turn the dial a
further two divisions anticlockwise. Switch off the
burner and replace the gas pressure switch cover.
FINAL CHECK
Check that all the covers to components have been
replaced and that locking devices are properly
secured. Check that the appliance control
instruments are set to safe limits.
Commissioning Is Now Complete
Switch on the electrical supply.
The burner will now operate until switched off.
a) by controlling instruments of the appliance
b) manually
c) by power failure. Upon restoration of power,
the burner will restart automatically and follow
sequence.
RWF40 MODULATING CONTROL
Basic display
The diagram opposite shows the RWF40 after
switching on the supply voltage. This condition is
called the basic display. The actual operating value
and the currently active set-point will be shown.
Manual operation, self-optimization, the operating
parameter and the configuration levels can be
activated from this display.
To change the working set point.
The basic display shows the actual pressure/
temperature of the boiler in red and the required
set point pressure/temperature beneath in smaller
green digits.