Nu-Way MGN 3300 Instruction Manual

Installation & Maintenance Manual
MGN 3300 - 4000
Gas Burner
Tel:[phone] Fax: [phone] Email: in[email protected] Web: www.nu-way.co.uk

CONTENTS
BURNER & COMPONENT INDENTIFICATION ………………………………………………
3
INTRODUCTION ……………………………………………………………………………….
5
FEATURES ………………………………………………………………………………………..
5
Burner Capacity ………………………………………………………………………
5
Controls & Safety Systems ………………………………………………………………………
5
Operating Mode ………………………………………………………………………
5
Fuel ………………………………………………………………………
5
Weight ………………………………………………………………………
5
SITE CONDITIONS AND SERVICES ……………………………………………………………
5
Flue and Chimney Requirements ………………………………………………………………………
5
Plant Room Ventilation ………………………………………………………………………
5
Existing Appliances ………………………………………………………………………
6
Combustion Chamber Conditions ………………………………………………………………………
6
Gas Supply ………………………………………………………………………
6
Gas Boosters ………………………………………………………………………
6
Electrical Power Supply ………………………………………………………………………
6
UNPACKING AND ASSEMBLY…………………………………………………………………..
6
INSTALLATION …………………………………………………………………………………..
7
General ………………………………………………………………………
7
Fitting to the Appliance ………………………………………………………………………
7
Electrical Power Connection ………………………………………………………………………
7
ELECTRICAL DATA ………………………………………………………………………………
7
BOOSTER WIRING DETAILS …………………………………………………………………...
9
BURNER CONTROL AND OPERATION ……………………………………………………….
9
Air Controls ………………………………………………………………………
9
Gas Controls ………………………………………………………………………
9
Control Panel ………………………………………………………………………
10
Flame Monitor ………………………………………………………………………
10
BURNER OPERATING SEQUENCE …………………………………………………………….
11
COMMISSIONING ………………………………………………………………………………
12
Safety ………………………………………………………………………
12
In An Emergency ………………………………………………………………………
12
Inspection ………………………………………………………………………
12
Initial Settings ………………………………………………………………………
13
Burner Dry Run ………………………………………………………………………
15
Burner Live Run ………………………………………………………………………
15
Final Checks ………………………………………………………………………
19
On Completing Commissioning ………………………………………………………………………
19
MGN 3300 & MGN 4000 Page 1

ROUTINE SAFETY CHECKS ……………………………………………………………………..
19
Combustion Air ………………………………………………………………………
19
Flame Detector ………………………………………………………………………
19
Valve Proving System ………………………………………………………………………
19
ROUTINE MAINTENANCE ……………………………………………………………………...
20
Combustion Air Fan ………………………………………………………………….
20
Burner Inner Assembly ………………………………………………………………….
20
Replacing the Air/Gas Ratio Controller ………………………………………………………………….
20
FAULT FINDING …………………………………………………………………………………
21
Burner Motor Fails to Start ………………………………………………………………….
21
Fans Starts and Burner goes to Lockout ………………………………………………………………….
22
Start Gas Flame Failure ………………………………………………………………….
22
Incorrect Rotation of Burner Motor ………………………………………………………………….
22
Main Flame Is Not Established ………………………………………………………………….
23
Burner Motor only runs Continuously ………………………………………………………………….
23
Spare Parts ………………………………………………………………….
23
APPENDIX ………………………………………………………………………………………..
24
Combustion Head Details – MGN 3300 and MGN 4000 ………………………………………….....
24
Burner Performance Envelopes and Supply Pressures ……………………………………………..
25
COMMISSIONING SHEET ……………………………………………………………………...
28
BURNER MODIFICATION RECORD …………………………………………………………..
29
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 UK it is a legal requirement tha
t
these engineers should also be CORGI registered. The manufacturer 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. Your attention is drawn to the Emergency Instructions
on Page 11.
EUROPEAN BOILER EFFICENCY DIRECTIVE (B.E.D.)
A
ll burners and boiler bodies marketed separately should comply with EN 267 (oil burners) or
EN676 (gas burners) and EN303-1 (boiler bodies).
Burner adjustments must be made in accordance with boiler manufacturers’ instructions, and
these must include flue gas temperatures, average water temperature, and CO2or O2
concentration.
MGN 3300 & MGN 4000 Page 2

BURNER & COMPONENT IDENTIFICATION for MGN 3300 & MGN 4000 BURNERS
Standard Burner Arrangement shown
All dimensions are in mm.
Item Description
1 Burner Casing
2 Flame Tube
3 Fan Motor
4 Air Inlet
5 Control Panel
6 Gas Train
7 Air Pressure Switch
MGN 3300 & MGN 4000 Page 3

BURNER & COMPONENT IDENTIFICATION for MGN 3300 & MGN 4000 BURNERS
Standard Burner Arrangement shown
All dimensions are in mm.
MGN 3300 & MGN 4000 Page 4

INTRODUCTION
This manual has been produced to enable users to install, commission and use MGN burners safely and
efficiently. At each stage the conditions that should be met and the adjustment and other actions that
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.
Literature on the proprietary components used in the MGN burner systems is available on request.
FEATURES
Developed through extensive field experience in the UK and overseas markets, the MGN series meets the
current and future test authority requirements in these markets and sets new standards in efficient and
reliable operation. MGN burners are designed for flange mounting to the appliance frontplate and they
are delivered ready to install with a pre-wired packaged control system and plug-in gas train.
Burner Capacity
MGN 3300 (2 Models): 2617 to 3294 kW MGN 4000 (3 Models): 3294 to 3926 kW
Controls and Safety Systems
MGN burners are fitted with a combustion air flow control system and an air/gas ratio controller which,
together, ensure smooth starting and optimum operating 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 gas pressure switches and a valve proving system.
Continuous flame supervision is provided by an ultraviolet (UV) cell and automatic programming control
unit.
Operating Mode
In standard form MGN burners are fitted with control systems which provide two-stage (high/low)
operation over a turndown range of 2:1. fully modulating systems with a turndown range of 2.5:1 can be
supplied on request – please refer to the modulating gas burner supplement.
Fuel
MGN burners are normally configured for natural gas. Systems suitable for other fuels – for example,
Towns Gas or Liquefied petroleum gas (LPG) – can be supplied on request.
Weight
319 kg approx.
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 fired appliances and that the proposed
installation complies with all Local 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.
Plant Room Ventilation
The burner must be supplied with dust-free air at sufficient rates for all firing conditions, in accordance
with the appropriate Standards.
MGN 3300 & MGN 4000 Page 5

Existing Appliances
The appliance should be prepared for installation of the MGN 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 for gas firing shall be
referred to the appliance manufacturer.
Combustion Chamber Conditions
When the burner is fitted to an appliance designed to work under balanced or negative combustion
chamber pressure conditions the over-fire draught must not exceed 0.25 mbar.
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 should be used to monitor the
pressure downstream of the booster and prevent the burner going to high fire 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.
Electrical Power Supply
A three-phase 50Hz supply is required. Power requirements are listed in the Table on Page 7. The power
supply provided must comply with all relevant Codes and Standards.
UNPACKING AND ASSEMBLY
To safeguard against damage in transit, MGN burners are supplied in partly assembled form, comprising
two units:
- The burner body, complete with control package and flame tube assembly.
- The gas control train.
To assemble the burner:
- Fit the gas control train to the burner body using the gasket supplied, ensuring that the gasket is fitted
correctly with all the holes corresponding with those on the burner flange.
- Connect the air inlet/impulse pipe from the SKP75 air/gas ratio controller to the left-hand side of the
burner body.
- Connect the multi-pin plug on the gas valve train to the socket on the rear of the control package.
Note: In some circumstances it may be advisable to fit the burner casing to the appliance before attaching
the gas control train.
MGN 3300 & MGN 4000 Page 6

INSTALLATION
General
Ensure that the appliance is suitable for the heat input of the burner. If there is any doubt in this area
reference shall be made to the appliance manufacturer. Detailed burner performance data are presented
in the Appendix of this handbook.
Fitting to the Appliance
If the burner is to be fitted to a new appliance refer to the appliance manufacturer’s recommendations. If
the burner is to be fitted to an existing appliance a mounting flange must be provided as detailed in the
Section on Burner& Components Identification. Ensure that the joint between the burner and the
mounting flange is sealed effectively using the gasket provided.
The flame tube should not extend beyond the inner face of the appliance combustion chamber unless
extensions are specified by the appliance manufacturer, for example in the case of reverse flame boilers.
Electrical Power Connection
Connect a three-phase, 50Hz electrical supply to the burner, observing all applicable Codes and Standards.
The electrical connections required are shown below and in the wiring diagram contained in the
instruction pack attached to the burner. These diagrams also show the external auxiliary control
connections which must be made.
If the burner is supplied as part of a packaged appliance/burner unit refer to the appliance manufacturer’s
instructions.
ELECTRICAL DATA
Electrical Connections
Electrical Power Requirements
MGN 3300 MGN 4000
Units -36 -41 -36 -41 -44
Mains Supply V±10% 400 400 400 400 400
Frequency Hz 50 50 50 50 50
Burner Motor kW 7.5 11 7.5 11 15
Start Current A 65 72 65 72 92
Full load Current A 15.0 22.8 15.0 22.8 29.7
MGN 3300 & MGN 4000 Page 7

EXTERNAL WIRING CONNECTIONS FOR MGN SERIES BURNERS
MGN 3300 & MGN 4000 Page 8
MODULATING
Note:
Control Loop is via Alarm 1 in TLK Control
For Modulating remove plug-in loose
connector on control pack
BLACK BROWN/BLACK
GREEN
BROWN
3PH SUPPLY MPA HIGH/LOW
GAS TRAIN
MPA TLK MOD
BROWN/BLACK
PTC
WATER TEMP. SENSOR
KTY 81 - 121 B8
PRESSURE TRANSMITTER
0-20 mA OUTPUT
MIDAS JP 401001
BLACK
BLACK

BOOSTER WIRING DETAILS
This applies to a Nu-way single booster wired to drawing numbers WA4-6278 or WA4-6770 only. For
further details please refer to Nu-way.
BURNER CONTROL AND OPERATION
All personnel concerned with commissioning and/or operation of MGN burners shall familiarise themselves
with the information presented in this Section.
Air Controls
Air Regulator
The flow of combustion air into the burner is controlled by an adjustable air damper located inside the air
inlet cover on the right-hand side (in all cases, such descriptions refer to the system as viewed from the
rear) of the burner. The damper is controlled by a three-position servo motor. The high and low fire
positions are adjustable. A fully closed position is provided to prevent air flowing through the appliance
when the burner is not in operation.
Air Diffuser
The air diffuser is fitted to the front of the burner assembly, within the flame tube (refer to the Appendix).
This diffuser controls the combustion air flow and creates a pressure drop across the burner head,
promoting good fuel/air mixing and flame stability.
Air Pressure Switch
The air pressure switch is located on the left side of the burner casing. Its function is to ensure that
combustion air flow is adequate at any stage beyond the first few seconds of the pre-purge sequence will
result in burner lockout.
Gas Controls
The gas train fitted is shown below.
Gas Nozzle
The gas nozzle is fitted to the front of the burner assembly, within the flame tube (refer to the Appendix).
The gas ports in this nozzle are sized in accordance with the rating of the burner and the gas to be used.
MGN 3300 & MGN 4000 Page 9
GAS TRAIN (View as installed from rear of the burner)
Item Description
1 Main Safety Valve
2 Low Gas Pressure Switch
3 Pressure Proving System
4 Combined Valve & Regulator
5 Min/Max Pressure Switch
6 Start Gas Solenoid Valve
7 Start Gas Governor
8 High Gas Pressure Switch
9 Burner Connection Flange
Link terminals 4 to
7
Live wire from burner to terminal 13 on the burner terminal block
1 2 3 4 5 6 7 8 9 10
Booster terminals

High Gas Pressure Switch
A high gas pressure switch is fitted to ensure that any increase in gas supply pressure above the level
needed to maintain the set conditions results in a safe burner shutdown. In this event a fault will be
indicated on the air/gas ratio controller. The pressure switch is factory set to the maximum value. Final
adjustment of the setting of this switch is described in the Section on Commissioning.
Low Gas Pressure Switch
Provision of a low gas pressure switch is required by European Standard EN676 – Automatic forced draught
burners for gaseous fuels. This pressure switch is fitted to all burners which carry the CE marking but it may
not be fitted to non-CE marked burners.
The low gas pressure switch monitors inlet gas pressure and ensures that any decrease in gas pressure
below the value needed to maintain satisfactory combustion results in a safe burner shutdown. Final
adjustment of the setting of this switch is described in the Section on Commissioning.
Gas Valve Train
In addition to the pressure switches noted above, the gas control train includes an air/gas ratio controller,
automatic safety shut-off valves and a governor in the start gas line. The upstream safety shut-off valve is of
the slow acting type and the speed of its initial opening can be varied.
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 System
A valve proving system, as shown schematically, is
standard on all MGN 3300 and MGN 4000 burners.
When the burner operating sequence is initiated, the burner control box energises the proving system,
which then carries out the following checks:
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.
V1, V2 and V3 remain closed for 23 seconds while the minimum side of the gas pressure switch checks
for an increase in pressure. If no increase occurs there is no leakage past V1 and the sequence
continues.
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.
Control Panel
The programming burner controller, ignition transformer, contactors and other items are located in an
enclosure mounted on the left side of the burner On/Off switch and two neon indicator 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
In standard configuration, MGN burners are fitted with continuous flame supervision systems which use
ultraviolet (UV) cells to detect the presence of the flame.
MGN 3300 & MGN 4000 Page 10

BURNER OPERATING SEQUENCE
After the proving cycle described above, the MGN burner operating sequence (refer to the controller
sequence diagram below) continues with a pre-purge period on full air. Gas is then supplied to the burner
at start rate and ignition initiated. Start gas flame proving is followed by establishment of the main flame,
at which point the burner controller will continue to its normal operating position and the operation of the
burner will be controlled by the pressure and/or temperature requirements of the appliance.
SEQUENCE DIAGRAM AND TIMING CHART
Time Controller Type
(s) TMG 740-3
MOD43-35 LFL 1.333 Description
T1 40 40 Pre-purge
T2 4 6 Pre-ignition
T3 3 3 Safety Lockout Time
T4 Not applicable to High/Low
Operation Delay start Rate to Main Flame – Single Stage
T5 9 12 Delay Start Rate to Main Flame – Multi Stage
T6 6 12 Delay between Main Flame Low &
Main Flame High (Two Stage Burners)
T7 10 18 Post-purge
T8 8 12 Air Pressure Switch Interlock
T9 80 91 Total Start Time
T total 90 106 Total Cycle Time of Controller
NOTE: The pre-purge times shown refer to the control box only. The air damper control will extend the
total burner purge time up to a maximum of 127 seconds depending on the firing rate and air
requirements of the appliance.
MGN 3300 & MGN 4000 Page 11

COMMISSIONING
Safety
It is essential that commissioning shall be undertaken only by suitably qualified and experienced personnel.
In the case of MGN burners, commissioning engineers should be experienced in commissioning forced
draught gas burners.
In the UK it is a legal requirement that commissioning engineers must be CORGI registered. Nu-way can
accept no responsibility for consequential loss, damage or injury which results from a failure to follow the
commissioning instructions provided or from commissioning procedures being undertaken by unqualified
personnel.
In an Emergency
MGN burners are designed and constructed to meet all essential requirements of the Gas Appliance
Directive 90/396/EEC. When used in accordance with the instructions provided, MGN 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 GAS AND
ELECTRICITY SUPPLIES SHALL BE ISOLATED IMMEDIATELY and they shall remain isolated until the fault
has been identified and rectified.
Inspection
Before commissioning is begun it is important to:
- Check that the electrical wiring is complete and complies with all applicable Codes and Standards.
- Ensure that the fuses are fitted and are of the correct ratings.
- Check electrical earthing.
- Verify that the gas supply pipework is correctly sized and that it has been checked for leakage.
- Ensure that the manual gas isolation valve at the inlet to the gas train is operable, fully closed and leak
tight.
- Make all personnel involved in the commissioning aware of the location of the emergency gas and
electricity isolation points.
- Check that fittings such as purge and test points are available.
- Establish that the appliance is in an appropriate and safe condition to be fired, for example, that there
is water in the boiler.
- Set the appliance controls to call for heat.
- Check the appliance’s ventilation and flueing arrangements.
- Ensure that any warning notices appropriate to the commissioning procedure are in position.
- Ensure that all necessary tools and test equipment are available and ready for use. Essential items
include a manometer or other approved pressure measuring instrument and a means of analysing the
flue products for carbon dioxide (CO2), oxygen (O2) and carbon monoxide (CO).
- Check that all relevant documentation is available, including, where appropriate:
- The agreed plant performance specification
- Plant drawings and pipework layouts.
- Electrical logic and wiring diagrams.
- Certificates confirming satisfactory completion of procedures such as soundness
testing, purging and electrical safety tests.
-Commissioning, operating and maintenance instructions for the plant.
- Establish that the operation of plant other than that being commissioned will not have an adverse effect
on the operation of the plant to be commissioned and similarly, that the operation of the plant to be
commissioned will not have an adverse effect on other plant.
- Confirm that the operation of adjacent plant and machinery will not constitute a hazard to the
personnel involved in commissioning.
MGN 3300 & MGN 4000 Page 12

Initial Settings
To prepare the burner for commissioning:-
1. Remove the cover from the air damper motor which is located in the top section of the air inlet cover.
Access is gained by removing the six screws retaining the top plate and the four screws retaining the
cover plate in the top right face of the air inlet cover. Check the cam positions and adjust as necessary,
referring to the settings shown below.
AIR DAMPER SETTING
2. Remove the small plate on top of the governor section of the air/gas ratio controller. Referring to the
diagram on Page 14, set the air/gas ratio on scale (1) to 0.8 by adjusting screw (1), anti-clockwise to
increase, clockwise to decrease. Set the ratio on the remaining scale to half a division on the positive
side of ‘0’ by adjusting screw (2) in the same way; anti-clockwise to increase, clockwise to decrease.
3. Remove the cap from the start gas governor and set the adjusting screw approximately half-way
between the maximum and minimum settings, turning the screw clockwise to increase the setting and
anti-clockwise to decrease it. Replace the cap. Never adjust the governor to its maximum setting.
4. Set the ignition electrode gap to 2.5 to 3 mm.
MGN 3300 & MGN 4000 Page 13
Cam Function Initial
Setting
1 Full Air Shut-Off
(Factory Set) 0 Deg
2 Low Fire Air 15 Deg
3 High Fire Air 60 Deg
NOTES:
1. The full air shut-off cam (1) is factory set and under normal circumstances should not require further
adjustment.
2. Setting of low and high fire air flow is by manual adjustment of cams 2 & 3. A scale is provided at
the end of the cam stack for guidance and adjustments are made using the screw adjusters situated
within the cam disk body.
3. The internal electrical connections are detailed on the inside of the motor lid for reference and fault
finding. The motor will traverse 90° within a maximum of 30 seconds.

AIR/GAS RATIO CONTROLLER
MGN 3300 & MGN 4000 Page 14
Item Function
1 Adjustment and indication of the gas/air ratio (High Fire Setting)
2 Adjustment and indication of the parallel displacement of the characteristic
(Low Fire Setting)
3 Vented to atmosphere
4 Connection to the gas line
5 Connection to the combustion air supply at the burner head
6 Indication of the valve stroke

Burner Dry Run
The following procedure should be followed. it is important that a complete and flawless dry run be
completed before gas is supplied to the system.
1. Check that the gas and electrical power supplies to the burner are turned off.
2. Check that the manual gas isolation valve is closed.
3. Check that the gas pipework between the plant isolation valve and the safety shut-off valves has been
tested for soundness and purged in accordance with an appropriate Procedure, for example, IGE/UP/1
Soundness testing and purging on industrial and commercial premises.
4. Ensure that the flame detection system detects a the presence of a simulated flame, or where
permissible, an independent flame source.
5. Remove the control panel cover and remove the low fire hold link. On the terminal strip, remove the
wire link between terminals 52 and 53 (if a gas booster is fitted, remove the wire from terminal 52) and
fit a temporary link between terminals 52 and 62. replace the cover.
6. Remove the cover from the low gas pressure switch and fit a temporary link between terminals 2 and 3.
Replace the cover.
7. Set the air pressure switch to minimum.
8. Establish the electrical supply to the burner and momentarily switch on the burner. Observe the
rotation of the combustion air fan motor, which should be anti-clockwise viewed from the motor end.
if the direction of rotation is incorrect refer to the Section of this handbook on Fault Finding.
9. If the fan rotation is correct switch on the burner. the gas pressure proving system will lock out.
10. The burner motor will begin to run:
a. Immediately if the system was switched off during normal operation.
b. On pressing the reset button on the control box.
If at this stage the burner goes to lockout refer to the Section on Fault Finding.
11. The burner will proceed through its ignition sequence. check that an ignition spark is present. If there
is no spark and the burner goes to lockout the air pressure switch may require adjustment – refer to the
Section on Fault Finding.
12. The ignition spark will cease and the system will go to lockout. Switch off the burner and the electrical
supply to the burner.
13. Remove the control panel cover and replace the low fire hold link. Remove the temporary link
between terminals 52 and 62 and replace the booster wire (terminal 52) or the link between 52 and
53 as appropriate. Replace the cover. Remove the temporary link fitted to the low gas pressure switch
and replace the cover.
14. The burner’s safety systems have now been proven and commissioning can proceed to the next stage.
Burner Live Run
The instructions in this section are presented as a continuous sequence. No separate set of actions (for
example, checking the flame signal) should be followed in isolation without paying particular attention to
any safety precautions such as isolating the electrical supply to the burner which should precede such
actions. At all stages the operation of the burner should be checked against the programming controller
sequence diagram on Page 11.
Before proceeding, check again that:
- The electrical wiring is complete and complies with all relevant Codes and Standards.
- All fuses are fitted and are of the correct ratings.
- The gas supply pipework is correctly installed and has been leak tested. If at any time during
commissioning there is a SMELL OF GAS the gas and electricity supplies must be isolated and the leak
sealed before proceeding.
- The appliance is in an appropriate and safe condition to be fired.
- The appliance controls are set to call for heat.
MGN 3300 & MGN 4000 Page 15

Gas Supply Pressure
The main gas safety valve is capable of withstanding gas inlet pressures up to 200 mbar. For MGN 3300
and MGN 4000 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:
1. Fit a manometer or other approved pressure measuring instrument to the pressure test point on the
upsteam side of the first safety shut-off valve.
2. Open the manual gas isolation valve at the inlet to the gas train.
3. Check that the gas pressure is adequate.
Establishing the Start Gas Flame
1. Remove the control panel cover and remove the pilot check link. Replace the cover.
2. Establish the electrical supply to the burner and switch on the burner.
3. Check the operation of the valve proving system by following the procedures described in the
Section on Routine Safety Checks.
4. The burner controller will run through its sequence, initiating the ignition spark and opening the start
gas safety shut-off valve.
5. The start gas flame will be established and the UV cell will begin monitoring. The burner will operate
continuously at start gas rate.
6. Confirm the leak tightness of the pipework downstream of the start gas safety shut-off valve.
7. Switch off the burner. Switch on the burner and allow the ignition sequence to be repeated,
confirming that the start gas flame is reliable.
8. Switch off the burner and the electrical power supply to the burner. remove the control panel cover
and replace the pilot check link. Replace the cover.
Setting Main Flame Rates and Air/Gas Ratios
From this point the commissioning process is concerned with setting the main and start gas flow rates to
appropriate values and ensuring that the combustion quality of the system is within acceptable limits.
During this process:
AFTER EACH ADJUSTMENT check the flue gas analysis and gas flow rate.
ALWAYS use approved and calibrated test equipment.
NEVER rely on visual observation of the flame as a guide to combustion quality.
1. Fit a manometer or other approved pressure measuring instrument to the gas pressure test point
nearest to the burner head. The relationship between the pressure at this point and burner heat
input is shown in the graphs in the Appendix. this information is provided only as a guide and it
should not be used in conjunction with pressure measurements as a substitute for accurate
measurement of gas flow rate using, for example, a gas meter.
2. Ensure that the flue gas analysis equipment is functioning.
3. Close the manual gas isolation valve at the inlet to the gas train to an opening of approximately 20%.
4. Set the gas inlet pressure switch to its minimum value.
5. Remove the control panel cover and remove the low fire hold link. Replace the cover.
6. Establish the electrical supply to the burner and switch on the burner.
7. The burner controller will run through its sequence, initiating the ignition spark and opening the start
gas safety shut-off valve. The start gas flame will be established and the UV cell will begin monitoring.
8. The main gas control valve will open and low fire will be established. Open the upstream manual
valve slowly until it is fully open, observing the CO level.
9. If the CO level is too high (see below) reset the low fire adjusting screw (2) on the air/gas ratio
controller (refer to the diagram on Page 14) until an acceptable figure is achieved. In extreme cases
the adjustment on screw (2) may be exhausted without achieving an acceptable CO level. In this
event, reset the high fire adjusting screw (1) until an acceptable CO level is achieved.
MGN 3300 & MGN 4000 Page 16

10 Confirm the leak tightness of the pipework downstream of the main gas safety shut-off valve using a
proprietary detection fluid.
11 Switch off the burner and the electrical power supply to the burner.
12 Remove the control panel cover and refit the low fire hold link. Replace the cover.
13 Establish the electrical supply to the burner and switch on the burner. The burner controller will run
through its sequence. Low fire will be established, expanding to main flame. Monitor the flame
visually during the transition from low to high fire. If the flame becomes more intense and compact
this indicates an excess of combustion air. If the flame becomes large and shapeless this indicates an
excess of fuel. Either condition is acceptable at this stage provided that the flame is stable and the
commissioning process continues immediately. If in doubt, switch off the burner and adjust screw (1)
on the air/gas ratio controller appropriately before restarting the burner.
14 With the burner running on high fire measure the flue CO2level and adjust screw (1) to bring the
level to between 9.5 and 10%. Note that at this stage the burner may be overfiring the appliance and
producing excessively high levels of CO.
15 Switch off the burner and the electrical power supply to the burner. Remove the control panel and
remove the low fire hold link. Replace the cover. Establish the electrical supply to the burner and
switch on the burner. Allow the burner controller to run through its cycle until the burner is running
on low fire.
16 Adjust the low fire adjusting screw (2) to bring the CO2level to between 9.0 and 9.5%.
17 Changing the low fire setting on the air/gas ratio controller will have a slight effect on the high fire
setting. It may therefore be necessary to repeat steps 14 to 16 several times in order to achieve
acceptable levels of CO2at both firing rates.
18 With the burner running on high fire check the gas flow rate with an appropriate instrument,
ensuring that the instrument has been calibrated before use. If the flow rate is to be measured using
the main site gas meter or a supplementary meter ensure that all other gas appliances served by that
meter are isolated. If it is necessary to adjust the gas flow rate this can be done by varying the air
damper opening.
19 Check the gas flow rate with the burner running on low fire. The low fire rate should not be less than
50% of the high fire rate (2:1 turndown). The gas rate can be adjusted by varying the low fire
position of the air damper. Care should be taken not to exceed the limits of the burner performance
envelope shown in the Appendix.
20 Analyse the flue products on both high and low fire. In both cases appropriate figures are:
Carbon dioxide (CO2) : 9 to 10%
Oxygen (O2) : 3 to 5%
Carbon monoxide (CO) : Less than 93 parts per million (ppm), dry air-free.
Setting The Start Gas Rate
1 Switch off the burner and the electrical power supply to the burner.
2 Remove the control panel cover and remove the pilot check link. Replace the cover.
3 Establish the electrical supply to the burner and switch on the burner. Allow the burner to light and
establish the start gas flame.
4 Check the gas flow rate. The appropriate rate is 25% of the low rate for the main flame. The start gas
rate should never be set at a level higher than 33% of the main flame.
5 If it is necessary to adjust the start gas rate, turn the adjusting screw in the start gas pressure governor
clockwise to increase the gas rate and anti-clockwise to reduce it. Make small adjustments and check
the gas rate after each change.
6 Switch off the burner and the electrical power supply to the burner. Remove the control panel cover
and replace the pilot check link.
MGN 3300 & MGN 4000 Page 17

Checking The Flame Signal
1 Disconnect the flame signal check link.
2 Connect a DC ammeter across the terminals.
3 Establish the electrical supply to the burner and switch on the burner. Allow the burner to light and
operate normally.
4 Observe the reading on the ammeter at all firing levels including start gas. A steady reading in excess
of 7 microamps is satisfactory. Lower readings may cause intermittent burner lockout and indicate a
need for adjustment of the burner settings - refer to the Section on Fault Finding.
5 Switch off the burner and the electrical power supply to the burner. Disconnect the ammeter and
replace the flame signal check link. Replace the control panel cover.
Setting The Air Pressure Switch
1 Remove the air pressure switch cover.
2 Fit a manometer or other approved pressure measuring instrument to the pressure switch to enable a
comparison to be made between the pressure switch indicator and the measured pressure.
3 Remove the control panel cover and remove the low fire hold link. Replace the cover.
4 Establish the electrical supply to the burner and switch on the burner. Allow the burner to proceed
through its sequence until it is operating on low fire.
5 Turn the adjusting dial on the pressure switch clockwise slowly until the flame is extinguished and
the burner goes to lockout.
6 Turn the dial one division anti-clockwise and reset the burner. If lockout occurs again, turn the dial a
further division anti-clockwise and reset the burner. Repeat this process until the burner lights and
runs satisfactorily.
7 Turn the adjusting dial a further two divisions anti-clockwise.
8 Switch off the burner and the electrical power supply to the burner. Remove the manometer.
Replace the pressure switch cover.
9 Remove the control panel cover and replace the low fire hold link. Replace the cover.
Setting The High Gas Pressure Switch
1 Remove the cover from the high gas pressure switch.
2 Establish the electrical supply to the burner and switch on the burner. Allow the burner to proceed
through its operating sequence until it is operating on high fire.
3 Turn the adjusting dial on the pressure switch anti-clockwise slowly until the switch trips, causing the
pressure switch indicating light to be illuminated and the burner to shut down.
4 Turn the adjusting dial one division clockwise.
5 Refit the cover and reset the pressure switch by pressing the button on the cover. The burner will
restart.
Setting The Low Gas Pressure Switch
1 Switch off the burner and the electrical power supply to the burner.
2 Remove the cover from the low gas pressure switch.
3 Establish the electrical supply to the burner and switch on the burner. Allow the burner to proceed
through its operating sequence until it is operating on high fire.
4 Turn the adjusting dial on the pressure switch clockwise slowly until the switch trips, causing the
burner to shut down. Turn the adjusting dial anti-clockwise slowly until the burner restarts and main
flame is established.
5 Repeat step (4) above.
6 Turn the dial a further two divisions anti-clockwise.
7 Switch off the burner and the electrical power supply to the burner. Replace the pressure switch
cover.
MGN 3300 & MGN 4000 Page 18

Final Checks
1 Check that all covers have been replaced and that all locking devices are secure.
2 Check the operation of the appliance control instruments and safety interlocks.
3 Ensure that the appliance controls are set to safe limits.
4 COMMISSIONING IS NOW COMPLETE.
5 Establish the electrical supply to the burner and switch on the burner. Allow the burner to proceed
through its operating sequence until it is operating on high fire. The burner will now operate
normally until:
(a) It is switched off by the appliance controls.
(b) It is switched off manually.
(c) There is an electrical power failure. In this event the burner will restart and run normally when
power is restored. No manual intervention is required.
On Completing Commissioning
When commissioning has been completed satisfactorily the commissioning engineer shall prepare a report,
which shall contain the following:
- Details of any modifications made to the system, together with revised drawings if necessary.
- Customer and plant details, including any serial numbers.
- Operating levels and settings, including flue gas analysis information.
This report shall be passed to the person responsible for the plant. This responsible person shall ensure
that:
1 All personnel concerned with operating, supervising and maintaining the plant receive instruction
covering:
- The way in which the plant operates and the locations and functions of the plant’s safety systems.
- The correct light-up and shutdown procedures.
- Adjustment of operating variables.
- Checking of plant interlocks.
- The plant’s maintenance requirements.
- The actions to be taken in the event of a fault condition.
2 Clear light-up and shutdown procedures are displayed on the plant and that the pipes, valves and
switches involved are clearly marked.
3 CLEAR AND CONCISE EMERGENCY SHUTDOWN PROCEDURES ARE DISPLAYED.
ROUTINE SAFETY CHECKS
THESE CHECKS SHOULD BE CARRIED OUT ONLY BY APPROPRIATELY QUALIFIED AND
EXPERIENCED PERSONNEL.
Combustion Air
Check that the plant room is well ventilated at all times and inspect the burner air inlet frequently to
ensure that there is no obstruction to the air flow.
Flame Detector
- Remove the UV cell from the burner casing and cover the quartz glass envelope to exclude light. Care
should be taken not to touch the glass.
- Establish the electrical supply to the burner and switch on the burner. The burner should go to lockout
at the end of the ignition cycle.
- Switch off the burner and the electrical supply to the burner. Replace the UV cell. Establish the
electrical supply to the burner and switch on the burner. Reset the lockout.
Valve Proving System
- Introduce a gas leak by slackening the screw in the pressure test point between the main valves.
- Establish the electrical supply to the burner and switch on the burner. The valve proving system
should lock out through falling gas pressure as the burner runs through its start cycle.
- Re-tighten the screw in the pressure test point and reset the lockout button on the valve proving
system.
MGN 3300 & MGN 4000 Page 19