Nu-Way PG Series User manual

Page A.1
P Series Contents
HANDBOOK
PG Series Automatic Gas Burner
Fully Modulating
®
Microprocessor MM Mk5 Control

P Series ContentsPage A.2
CONTENTS
IMPORTANT INFORMATION .............................................................................. A.4
SAFETY ................................................................................................................... A.4
EMERGENCY INSTRUCTIONS ........................................................................................ A.4
EUROPEAN BOILER EFFICIENCY DIRECTIVE (B.E.D.) ........................................................ A.4
GENERAL INFORMATION ................................................................................. B.1
INTRODUCTION ....................................................................................................... B.2
FEATURES ............................................................................................................... B.2
Burner Designation ..............................................................................................................B.2
Burner Capacity ................................................................................................................... B.2
Fuel .....................................................................................................................................B.2
Controls...............................................................................................................................B.2
Operating Mode ..................................................................................................................B.2
SITE CONDITIONS AND SERVICES ................................................................................ B.3
Flue and Chimney Requirements .........................................................................................B.3
Plant Room Ventilation ........................................................................................................B.3
xisting Appliances ..............................................................................................................B.3
Gas Supply .......................................................................................................................... B.4
Gas Boosters........................................................................................................................B.4
Oil Supply ...........................................................................................................................B.4
lectrical Power Supply ........................................................................................................B.5
BURNER PACKAGING, ASSEMBLY AND INSTALLATION ........................................................ B.5
Packaging For Transit ............................................................................................................B.5
Assembly And Installation ....................................................................................................B.5
Fitting To The Appliance.......................................................................................................B.5
Air Supply ............................................................................................................................B.6
Combustion Chamber Conditions ........................................................................................B.6
lectrical Power Supply ........................................................................................................B.6
TECHNICAL SPECIFICATION .............................................................................. C.1
BURNER SPECIFICATION SHEET .................................................................................... C.2
BURNER AND COMPONENT IDENTIFICATION .................................................................. C.3
BURNER CONTROL AND OPERATION ........................................................................... C.3
Air Controls .........................................................................................................................C.3
Gas Controls ........................................................................................................................C.3
Control Panel .......................................................................................................................C.4
Burner Sequence Controller .................................................................................................C.4
Flame Monitor .....................................................................................................................C.4
Modulating Control And Operation .....................................................................................C.4
BURNER OPERATING SEQUENCE .................................................................................. C.5
COMBUSTION HEAD DETAILS ..................................................................................... C.5
COMMISSIONING ......................................................................................... D.1
INDIVIDUAL SETTING RECORD .................................................................................... D.2
SAFETY ................................................................................................................... D.2
EMERGENCY INSTRUCTIONS ........................................................................................ D.2
INSPECTION ............................................................................................................ D.2

Page A.3
P Series Contents
COMMISSIONING THE BURNER ................................................................................... D.3
ntering the Pass Code ........................................................................................................ D.3
Options and Parameters...................................................................................................... D.3
INITIAL SETTINGS ..................................................................................................... D.4
DRY RUN .............................................................................................................. D.4
LIVE RUN ............................................................................................................... D.5
General .............................................................................................................................. D.5
Gas Supply Pressure ............................................................................................................ D.5
Initial Checks ...................................................................................................................... D.5
stablishing The Gas Flame ................................................................................................. D.6
Setting The Low Gas Pressure Switch .................................................................................. D.8
FINAL COMMISSIONING STAGES .................................................................................. D.8
Checking The Flame Signal ................................................................................................. D.8
Setting The Air Pressure Switch ........................................................................................... D.8
Set-Point Adjustment .......................................................................................................... D.9
Final Checks........................................................................................................................ D.9
On Completing Commissioning........................................................................................... D.9
COMMISSIONING SHEET : GAS ................................................................................. D.11
OPERATION AND MAINTENANCE ....................................................................... E.1
NORMAL OPERATION .................................................................................................E.2
ROUTINE SAFETY CHECKS ...........................................................................................E.2
Combustion Air.................................................................................................................... .2
Flame Detector .................................................................................................................... .2
Valve Proving System............................................................................................................ .2
Low Gas Pressure Switch ..................................................................................................... .2
Combustion Air Pressure Switch........................................................................................... .2
ROUTINE MAINTENANCE ............................................................................................ E.3
Combustion Air Fan ............................................................................................................. .3
Burner Inner Assembly ......................................................................................................... .3
FAULT FINDING ......................................................................................................... E.3
rror Checking, Fault Analysis & Identification Codes............................................................ .3
Incorrect Rotation of the Fan Motor ..................................................................................... .4
Fan Motor Fails To Start ........................................................................................................ .4
Fan Motor Starts And Burner Goes To Lockout ..................................................................... .4
Start Flame Failure ............................................................................................................... .4
Main Gas Flame Is Not stablished ...................................................................................... .4
Fan Motor Only Runs Continuously ..................................................................................... .5
SPARE PARTS ............................................................................................................E.5
BURNER SERVICE RECORD .......................................................................................... E.6

P Series ContentsPage A.4
IMPORTANT INFORMATION
SAFETY
It is essential that the following instructions and adjustments are carried out by qualified engineers
that are experienced in forced draught gas and pressure jet oil burner commissioning. In the UK,
it is a legal requirement that these engineers working on a gas installation, as defined in the ‘Gas
Safety (Installation & Use) Regulations 1994’, must also be CORGI registered. Nu-way cannot be
held responsible 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
P Series Burners are designed and constructed to meet all applicable uropean Directives.
When used in accordance with the instructions provided, P Series Burners are unlikely to produce
a hazardous condition. If, however, such a condition should arise in connection with the burner,
the appliance or any instrument, machine or service in the vicinity of the burner, the FUEL AND
ELECTRICITY SUPPLIES SHALL BE ISOLATED IMMEDIATELY and they shall remain isolated
until the fault has been identified and rectified.
EUROPEAN BOILER EFFICIENCY DIRECTIVE (B.E.D.)
All burners and boiler bodies marketed separately within the uropean Union must comply with
N676 - Gas Burners, and N303 - 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.

Page B.1
PG Series General Information
GENERAL INFORMATION

PG Series General InformationPage B.2
INTRODUCTION
This handbook has been produced to enable users
to install, commission and use P Series burners
safely and efficiently. At each stage the conditions
that should be met and the adjustments and other
actions which should be carried out are detailed
and the locations of the various components and
adjustment mechanisms are identified. Where
appropriate, this information is supported by tables
and graphs.
iterature on the proprietary components used in
P Series burner systems is available on request.
FEATURES
The P Series of fully automatic burner equipment
is offered for industrial and air heater applications.
This is a versatile range of fully modulating burners
with a turndown of 3:1.
P Series burners meet current test authority
requirements both in the UK and overseas.
P Series burners are designed for flange mounting
to the appliance. All components are pre-wired,
input and output circuits being grouped for ease
of connection to the power supply and to electrical
equipment on the burner head and air damper.
arger sizes of PO and PDF burners can be supplied
with air/steam oil atomisation in place of the usual
pressure jet.
Burner Designation
Each burner is described by a comprehensive code
that defines all the important parameters of each
individual burner and is an important point of
reference for burners in service. In addition to the
burner casing size and maximum power output,
the code is composed as shown in the Table on
Page B.7.
Burner Capacity
The burner output (based on the gross calorific
value) is shown on the Burner Specification Sheet
on Page C.2 Technical Details.
Fuel
The PG burner is available for natural gas but, on
request, will be supplied for liquefied petroleum
gases ( PGs), towns gases or biogas.
Controls
The control panel, housed in a free-standing or
wall-mounted cabinet, is a purpose designed and
robustly constructed unit that complies with
relevant Standards and Codes of Practice and can
be tailored to individual customer requirements.
Depending on the burner specification, the control
panel incorporates such components as a burner
management sequence controller, a fuel selector
switch, modulating control gear, a starter for the
combustion air fan, starters for boiler feed water
pump, and safety devices e.g. low and high water
cut-out relays.
Air for combustion can be adjusted to give
maximum efficiency. An air pressure switch
provides safe shutdown if the combustion air
supply becomes insufficient for complete
combustion and the burner’s additional safety
systems include high and low pressure gas switches.
An ultraviolet (UV) cell and automatic programming
control unit provide continuous flame supervision.
Operating Mode
P Series burners are all fully modulating offering a
standard turndown of 3 to 1.
To ensure efficient operation of any boiler, two
requirements are of paramount importance. The
air to fuel ratio must be kept to a minimum whilst
being sufficient for complete combustion and the
settings for this condition, once arrived at, are
accurately repeated. The temperature or pressure
of the boiler must be monitored by the control
system and the correct amounts of fuel and air fired
to achieve the set value, variations from this set
point must be minimised even when the load
changes.
Modulation By Electro-Mechanical Systems
P Series burners can be supplied with a andis and
Staefa RWF40 modulating controller. This unit is
designed specifically for the control of boiler
temperature or steam pressure in oil- and gas-fired
heating plant.
The system comprises a reversible motor that is
coupled directly to the cam shaft of the modulating
unit. Two adjustable cams are mounted on this
shaft, one of which operates the air linkage and
the other, the modulating oil cam.
The air/fuel ratio is controlled by an SKP70
controller that matches the fuel gas flow to the air
flow. The SKP70 is linked to the combustion air
system by a pressure impulse pipe.

Page B.3
PG Series General Information
Modulation By Electronic Cam System
There is some inherent hysteresis in all mechanical
systems that traditionally involve cams and linkages
to characterise the air/fuel ratio.
To improve accuracy, P Series burners are now
normally supplied with a system that overcomes
all of these problems by utilising independently
operated servo-motor driven valves for the fuel and
air and the latest microprocessor technology.
This Micro Modulation system (MM) provides a
programmable and flexible means of optimising
combustion quality throughout the load range of
the boiler/burner unit whilst ensuring the
temperature is accurate to within 1°C and pressure
to within 1.5 psi by utilising P.I.D. control.
A control module contains a micro computer and
power supply. The display panel features touch-
sensitive key pad data entry, readouts and status
indicators; all protected beneath a tamper-proof
transparent plastic cover.
During commissioning, the paired values for fuel
and air are entered into the memory of the module.
Upto 15 positions in the load index of the burner’s
fuel delivery range are entered from maximum
down to the minimum start position. This
guarantees operation at the air/fuel ratios set during
commissioning.
By removing the inherent hysteresis of traditional
mechanical systems, combustion quality and fuel
efficiency are greatly improved.
The M.M. system may be expanded, by adding a
sampling unit and exhaust gas sampling probe, to
measure and display CO2, O2, CO and exhaust
temperature, together with boiler efficiency. This
is the M.M. Exhaust Gas Analysis Trim System
(M.M.E.G.A.).
This makes very small corrections to the air damper
position to ensure that the originally entered
commissioning data is adhered to, irrespective of
variations in stack pressure or barometric
conditions.
SITE CONDITIONS AND SERVICES
Flue and Chimney Requirements
It is important that:
- the flue pipe from the appliance and the joint
between this flue and the chimney are sealed
to prevent leakage of combustion products
- the flue pipe from the appliance does not
protrude into the chimney beyond the inside
wall
- the top of the flue or chimney shall be higher
than any roof within a radius of 10 metres
- checks are made to ensure that the chimney
is suitable for gas and oil-fired appliances and
that the proposed installation complies with
all ocal Authority and other regulations
covering such installations
- 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
- it is recommended that each appliance
should be exhausted into a separate flue.
Plant Room Ventilation
An adequate dust-free supply of fresh air is required
for the burner at both high and low levels in
accordance with the appropriate standards.
Existing Appliances
The appliance should be prepared for installation
of a P Series burner by thorough cleaning, including
the removal of all adhering tar, scale and dirt. An
inspection should also be carried out to ensure that
the appliance is in good condition. Any doubt
about the suitability of the appliance should be
referred to the manufacturer.
as Supply
The pipework supplying the gas 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 that is
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 to gas flow.
Natural gas is the usual fuel and has to be supplied
at an appropriate pressure, these pressures are
presented on the Burner Specification Sheet on
Page C.2 Technical Specifications

PG Series General InformationPage B.4
If the gaseous fuel is towns gas, liquefied petroleum
gas or biogas, then appropriate information,
supplemental to this handbook, will be supplied
with the burner.
as Boosters
When a gas booster is used, the gas pressure at
the booster inlet must not fall below 1 kPa (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.
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, that reduce both pipework
stresses and transmitted noise, is essential. 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.
Electrical Power Supply
A three phase 50 Hz electrical supply is required.
Power requirements are listed on the Burner
Specification Sheet on Page C.2 Technical
Specification. The power supply provided must
comply with all relevant Codes and Standards.
BURNER PACKAGING, ASSEMBLY
AND INSTALLATION
Packaging For Transit
All P Series modulating burners are supplied in
partly assembled form consisting of the following:
- burner head and air plenum chamber
- damper section with modulating air system
- gas train complete with proving system
- combustion air fan
- floor mounted burner control panel
Assembly And Installation
P Series burners are supplied in partly assembled
form comprising some or all of the units indicated
above, depending upon the type(s) of fuel to be
fired.
Make sure that the appliance is suitable for the
heat input of the burner. If there is any doubt in
this area, reference should be made to the
appliance manufacturer.
Fitting To The Appliance
If the burner is to be fitted to a new appliance
refer to the manufacturer’s recommendations.
If the burner is to be fitted to an existing appliance,
the burner front plate and appliance must be
prepared; the details of the drilling arrangements
are shown on Page B.7.
The chimney, flues, passageways and heat transfer
surfaces on the existing appliances must be
cleaned. An inspection should be carried out to
ensure that the appliance is in good condition. Any
doubt about the suitability of the appliance should
be referred to the manufacturer.
To assemble the burner:
1 Fit the burner head to the prepared appliance
front plate.
2 Ensure that the joint between the burner and
the mounting flange is sealed effectively using
the gasket provided. The flame tube should
not generally extend beyond the inner face
of the furnace brickwork or the front plate
protection, except where extensions have
been expressly specified by the appliance
manufacturer.
3 Fit the damper section to the burner head
using the fasteners and gasket provided.

Page B.5
PG Series General Information
4 Position the combustion air fan and connect
the damper section using the fasteners and
gasket provided. Depending on the appliance
layout it may be necessary for the customer
to provide a connecting duct section
between the damper and the fan scroll (not
supplied by Nu-way).
5 For PG burners, fit the gas valve train to the
burner head using the gasket provided,
ensuring that the gasket is fitted correctly with
all holes corresponding to those on the
burner flange. Note: In some circumstances
it may be advisable to fit the burner casing
to the appliance before attaching the gas
control train. It is recommended that lifting
gear should be employed if necessary.
6 ocate the control panel in the desired
position and make the necessary
connections between the burner head, and
other auxiliary appliance controls.
Reference must be made to the wiring diagrams
that are supplied with the burner (electrical
connection diagrams do not form part of this
handbook); all electrical wiring must comply with
all applicable Codes and Standards.
Air Supply
A floor-mounted fan provides the air supply for the
system, although the fan can be suspended for the
smaller sizes of burner. The flange on the
rectangular outlet is drilled for bolting onto the air
damper section of the burner unit. For safety, a wire
mesh guards the circular inlet of the fan. The motor
unit is enclosed, air-cooled and mounted on a rigid
base. The fan orientation/burner mounting
positions would have been specified by the
customer when the order was placed.
Combustion Chamber 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 0.05 kPa (0.2 inches water column, 0.5
mbar or 5 mm w.c.).
Should the over-fire draught exceed this value,
then steps should be taken to reduce it to or below
this level.
Electrical Power Supply
Connect the power supply to the burner observing
all applicable Codes and Standards. Reference
should be made to the wiring diagrams provided
in the instruction pack that is supplied with all P
Series burners and to those wiring diagrams in the
appliance manufacturer’s instructions.
All external auxiliary control circuits should be
connected with reference to the appropriate wiring
diagram. All systems and circuits should be checked
to ensure that correctly rated fuses are used.

SS
SS
SUPPLEMENTUPPLEMENT
UPPLEMENTUPPLEMENT
UPPLEMENT
TOTO
TOTO
TO HH
HH
HANDBOOKSANDBOOKS
ANDBOOKSANDBOOKS
ANDBOOKS
SS
SS
SPECIFICPECIFIC
PECIFICPECIFIC
PECIFICAA
AA
ATIONTION
TIONTION
TION CC
CC
CHANGESHANGES
HANGESHANGES
HANGES
SKP ASKP A
SKP ASKP A
SKP ACTUCTU
CTUCTU
CTUAA
AA
ATORTOR
TORTOR
TOR
UPGRADEUPGRADE
UPGRADEUPGRADE
UPGRADE
ANDAND
ANDAND
AND NN
NN
NEWEW
EWEW
EW
WW
WW
WIRINGIRING
IRINGIRING
IRING CC
CC
COLOL
OLOL
OLOURSOURS
OURSOURS
OURS
Supplement SKP & Wiring.PMD
Revision 310506A
SKP ASKP A
SKP ASKP A
SKP ACTUCTU
CTUCTU
CTUAA
AA
ATORSTORS
TORSTORS
TORS
A new range of valve actuators has been introduced by Siemens as an upgrade to the SKP range. The
new actuators SKP15, 25, 55 and 75, are replacements for the SKP10, 20, 50 & 70 which will
become obsolete. The new range of actuators will be introduced into the Nu-way range of Gas and
Duel Fuel Burners as from the 1st of June 2006.
The new range of SKP actuators have plug in connections so Nu-way can no longer use the actuators
as junction boxes and therefore a separate junction box will be introduced to gas trains (Similar to
valve proving configuration).
Spares supply for the SKP10, 20, 50 & 70 will continue until around January 2007 depending on
stock usage, in future the spares replacement for SKP valve actuators will be an upgrade kit
comprising of the new actuator plus the junction box and wiring harness to enable the fitting of the
SKP15, 25, 55 and 75 to burners originally fitted with the SKP10, 20, 50 & 70.
The new actuators are physically different however the function and adjustment remain the same,
they will fit all existing gas valves (VGD etc.) which are unaffected.
NN
NN
NEWEW
EWEW
EW WW
WW
WIRINGIRING
IRINGIRING
IRING CC
CC
COLOL
OLOL
OLOURSOURS
OURSOURS
OURS
In accordance with the Requirements for Electrical Installations BS 7671:2001 Amendment No 2 (the
IEE wiring regulations), wiring colour coding has been amended to Brown (L) and Blue (N) for single
phase power circuits and Brown (L1) Black (L2) and Grey (L3) and Blue (N) in three phase power
circuits from 1 June 2006.
Full details of the changes can be found in Amendment No 2 (AMD 14905) to BS 7671:2001 - which
is a free download from the IEE website (www.iee.org/cablecolours). They are also within the new
version of BS7671:2001 (Incorporating Amds 1& 2) published on 31st March; this new version of the
Wiring Regulations can be identified by its brown cover.

PG Series General InformationPage B.6
BURNER DESIGNATION CODE

Page B.7
PG Series General Information
BURNER MOUNTING DETAIL
\B_Gen\PG\B_Gen.pmd Re ision 031203A

PG Series General InformationPage B.8

Page C.1
PG Series MM Mk5 Technical Specification
TECHNICAL SPECIFICATION

PG Series MM Mk5 Technical SpecificationPage C.2
BURNER SPECIFICATION SHEET
MW
Components :
kW h
p
Am
p
s
Am
p
s
Am
p
s
kW h
p
kW
psi °C
psi °C
Other Services
Flow : psi
Flow : psi
Flow : psi
Comments :
Atomising Air :
Pressure :Steam Pre-heater :
Pressure :
Steam Atomiser:
Fuel 1 :
Fuel 2 :
Pressure :
Fuel Pressure And Temperature Requirements (At Burner Inlet) :
Pressure : Temp.
Pressure : Temp.
Oil Pump Manufacturer :
Fuel Modulating Motor :
Air Modulating Motor :
Air/Gas Ratio Controller :
Fuel Gas Valve Proving System :
Fuel 1 : Fuel 2 :
Oil Pre-heater Type :
Electrical Power Requirements :
Pre-heater :
Fan Motor Current Start :
Fan Motor Current Run :
HRC Fuse :
Oil Pump :
Fan Motor Power :
Model :
Serial No. :Specification No. :
The information contained on this sheet describes the burner as supplied by Nu-way. If the
burner is modified after delivery then this sheet should be updated as necessary.
Oil Atomising Method :
Modulation Controller :
Burner Sequence Controller :
Designation : Capacity :

Page C.3
PG Series MM Mk5 Technical Specification
BURNER AND COMPONENT
IDENTIFICATION
The general arrangement of a PG burner employing
Microprocessor Mini MM Mk. 5 modulation is
shown in the diagram Burner and Component
Identification on Page C. .
These diagrams are for illustrative purposes only
and actual components supplied may vary from
those shown.
BURNER CONTROL AND OPERATION
All personnel concerned with commissioning and/
or operation of PG Series burners should familiarise
themselves particularly with the information
presented in this section.
Air Controls
Air Damper
To control the air for combustion PDF burners have
an adjustable multi-blade damper located in a
rectangular section attached directly to the burner
casing (diagram on Pages C. ). This damper is
driven directly by a servo-motor and must be set
during commissioning.
Air Diffuser
An air diffuser (shown in the diagram Burner Head
& Inner Assembly on Page C.12) is fitted to the front
end of the inner assembly and is located within
the flame tube. It directs the combustion air flow
and creates a pressure drop across the burner head,
promoting good air/fuel mixing and flame stability.
Air Pressure Switch
The air pressure switch is located on the rear of
the burner casing. Its function is to ensure that the
combustion air flow is adequate under all operating
conditions.
An air flow failure at any stage beyond the first few
seconds of the pre-purge period will result in a
safe burner shutdown.
Gas Controls
PG burners with the Microprocessor Mini MM Mk.
5 modulating system, are supplied with a gas train
(see Gas Control Train Schematic on Page C.7). The
train is normally a separate unit that needs to be
connected to the burner body.
The supplied gas train comprises :
–a low gas pressure switch
–a safety shut-off valve
–a valve proving system
–a combined safety shut-off valve and pressure
governor
–a flow control valve actuated by the
modulating control system
Upstream Manual Gas Valve
The manual valve in the fuel gas supply
immediately upstream of the burner gas train, this
valve is not supplied by Nu-way. It MUST be
supplied and installed by the customer and is
shown on the diagram on Page C.7 as ‘Manual Gas
Isolation Valve (Not Supplied By Nu-way)’.
Low Gas Pressure Switch
The provision of a low gas pressure switch is
required by European Standard EN 7 ‘Automatic
Forced Draught Burners for Gaseous Fuels’ and is
fitted to all burners where necessary. The low gas
pressure switch monitors inlet gas pressure and
ensures that any decrease in pressure below the
value needed to maintain satisfactory combustion
results in a safe burner shutdown. The switch must
be set during commissioning.
Safety Shut-off Valve
This valve shuts off the fuel gas flow to the burner.
Valve Proving System
When the burner operating sequence is initiated,
the burner control box energises the valve proving
system, and in the event of a gas leak, prevents
burner start-up.
The Landis & Staefa LDU11 control unit is designed
to provide automatic gas valve proving (leakage
test) based on the pressure proving principle (see
diagram on Page C.7). The system comprises the
control unit, which is fixed to a bracket/terminal
box assembly close to the main valve block, and a
dual pressure switch, which is connected to the
test space between the main valves. The unit comes
pre-wired as part of the gas train harness.
When the appliance ‘calls for heat’, a signal, via
the burner sequence control box, energises the
valve proving system; this carries out a series of
tests before the burner can start. The two actuated
valves (V1 and V2) in the main fuel line are closed
when this signal is received. The sequence of
operation is as follows:
- The first step of the proving sequence is to
open the downstream gas valve (V2), this
vents any gas that is in the system via the gas
flow control valve. After five seconds valve
(V2) closes.

PG Series MM Mk5 Technical SpecificationPage C.4
- Both valves remain closed for 22.5 seconds
whilst the LDU11 unit checks that there is
no build up in pressure in the line between
the valves. If there is no rise in pressure this
proves that the first valve (V1) is gas tight and
that no gas is passing; the valve proving
system will now continue its sequence. If the
valve on the pressure side is leaking, pressure
will build up and the low gas switch will signal
the LDU11 unit to go to lock-out (the
program indicator then stops and indicates
‘Test 1’).
- This first main safety valve (V1) opens for five
seconds, which pressurises the line between
the valves, and then closes. Both valves
remain closed for 27.5 seconds whilst the
LDU11 unit and high gas pressure switch
check for a fall in pressure between the
valves.
If there is a fall in pressure, the proving system
will lock-out and the downstream main gas
valve (V2) should be checked as it may be
leaking. (The program indicator then stops
and indicates ‘Test 2’).
- If there is no fall in pressure then the system
is gas tight. The pressure proving system will
now allow the burner to continue its normal
operation.
The LDU11 unit carries out the low and high
pressure checks between the two gas valves prior
to commencement of each firing cycle.
If the pressure increases excessively during the first
test phase or decreases excessively during the
second test phase, the control unit inhibits burner
start-up and goes to lock-out. The lock-out re-set
button lights up and signals a fault. A program
indicator, which stops whenever a fault is signalled,
indicates which valve is leaking.
The control unit has to be re-set manually, either
on the unit itself or by a remote re-setting if this
has been fitted (do not press the re-set button for
more than 10 seconds).
Combined Safety Shut-off Valve and Governor
A combined safety shut-off valve and governor is
the first valve in the gas train that is supplied by
Nu-way. This valve is used to shut off the gas flow
and to control the gas pressure. It must be set
during commissioning (see Commissioning Section
D).
Manual Gas Valve
This is a manual shut-off valve to isolate the main
fuel flow.
Flow Control Valve
The valve is controlled by the modulation control
system (the valve positions over the burner input
range must be set during Commissioning), checking
the position of the control valve is carried out
continuously to ensure that the desired gas flow is
maintained.
Gas Nozzle
The gas and fuel oil nozzles that are fitted to the
front of the burner assembly, within the flame tube,
are shown on the diagram Burner Head & Inner
Assembly on Page C.12. The ports in these nozzles
are sized in accordance with the thermal rating and
the fuels to be fired.
Control Panel
The control panel is a separate unit, free-standing
or wall-mounted, that is positioned adjacent to the
burner unit. The panel design depends upon
whether the boiler is for water heating or steam
raising. The sequence controller, relays, indicating
lamps, panel isolating switch etc. are contained
within this unit.
The burner is also fitted with an ignitor/terminal
box on the side of the burner casing. This is a
junction for all electrical components that are held
in the free standing control panel.
Connections must be made between the control
panel and the terminal box.
Burner Sequence Controller
The burner sequence controller, together with the
flame monitoring system, provide a safe light-up
sequence for the burner.
A Landis & Staefa burner controller of the type
LFL1.3-- (see the diagram Burner Sequence
Controller : Landis & Staefa LFL1.3 on Page C.8) is
fitted as standard.
Flame Monitor
All PG Series burners are fitted with continuous
flame supervision systems employing an ultraviolet
(UV) cell to detect the presence of a flame.
Modulating Control And Operation
The burner employs a microprocessor modulating
controller. Detailed information of this system will
have been provided separately with the burner.

Page C.5
PG Series MM Mk5 Technical Specification
The control module contains a micro-computer
and power supply. The display panel has touch
sensitive key pad entry, readout and status
indicators, all protected beneath a tamper-proof
protective cover (see diagram Burner Modulation
Controller : Mini MM Mk. 5 on Page C.10).
The fuel gas and air flows are each controlled by
separate servo-motors (see diagram Positioning
Motor on Page C.10) driven by the modulation
controller.
One motor positions the air damper and the other
operates the fuel control butterfly valve by which
it is possible to control the input of gas. During
commissioning it is necessary to adjust the
potentiometers in these positioning motor
assemblies.
The position of each servo-motor is monitored by
a voltage dividing system enabling digitised
information to be encoded into the control
module’s memory. The relative positions of the air
and fuel motors are checked constantly by the
system at the rate of 50 times per second.
The modulation controller displays angular
positions of the air damper motor and fuel valve
motor. ‘Required’ and ‘Actual’ boiler temperatures
or pressures are also displayed.
During commissioning the Mini MM Mk. 5 must
be set at high flame, low flame and a number of
intermediate positions.
The commissioning procedure is provided in the
Section D, Commissioning. The Mini MM Mk. 5
manual, issued separately with the burner, should
be consulted for further information if required.
Temperature Detector
The temperature detector (shown in the diagram
on Page C.11) is specific to the modulation control
system and is available in various ranges.
Pressure Detector
The pressure detector (shown in the diagram on
Page C.11) is specific to the modulation control
system and is available in various ranges.
BURNER OPERATING SEQUENCE
The operating sequence of PG Series Burners (refer
to the diagram Burner Sequence Timing Chart on
Page C.9) begins with checks on external interlocks
and a check for no flame, a pre-purge period on
full air is then initiated.
Gas is supplied to the burner at start rate and
ignition initiated. Start gas flame proving is followed
by establishment of the main flame, after which
the burner modulates to high fire.
The burner sequence controller will then continue
to its normal operating position (i.e. it continues
to supervise the control functions and is therefore
able to shutdown the burner safely should this be
necessary), after driving to high fire, the burner will
be controlled by the modulation controller, an
electronic cam system, in response to the pressure
and/or temperature requirements of the appliance.
COMBUSTION HEAD DETAILS
The combustion head and inner assembly are
shown in the diagram Burner Head on Page C.12.

PG Series MM Mk5 Technical SpecificationPage C.6
BURNER AND COMPONENT IDENTIFICATION

Page C.7
PG Series MM Mk5 Technical Specification
GAS CONTROL TRAIN SCHEMATIC