Potterton NXR3 User manual

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NXR3
Installation, Operation and Maintenance Manual
To be kept by the user October 2010
heating specialists

INDEX
Section 1 Page
Fig. 1 - General Data & Dimensions 1
Table 1 - Boiler Dimensions 1
Table 2 - Combustion Chamber Data 1
Table 3 - Technical Data 2
- Explanatory Notes 3
- Clearances 4
Fig. 2 - Boiler Clearances 4
Fig. 3 - Boiler Footprint/Base Details 4
Section 2
- General Information 5
- Standard Supply 5
- Controls 5
- Optional Extras 5
- Shipping / Packaging 5
- Installation Standards 6
- Boiler Siting & Base 6
Section 3
- Ventilation 7
- Flues (General) 7
- Water Circulation Systems 7
- Boiler Protection 8
- System Water Quality 8
Section 4
- Boiler Erection 9
- Risk Assessment 9
- Manual Handling 9
- Personal Protective Equipment 9
- Confined Spaces 9
- Electrical Safety 9
- Packaging Details 9
- Preparation 9
- C.O.S.H.H 10
- Erection Checklist 10
- Boiler Erection 11
Fig. 4 - Section Assembly 11
Fig. 5 - Section Orientation 12
- Pulling Up Bars 12
Fig. 6 - Boiler Fittings Assembly 13
- Fittings Assembly 14
Fig. 7 - Baffles Assembly 14
Fig. 8 - Door Hinge Guide Assembly 14
- Insulation & Casing Assembly 15
Fig. 9 - Insulation Position 15
Fig. 10 - Casing Support Frame 15
- Casing Assembly 16
Fig. 11 - Casing Side Panel Assembly 16
Fig. 12 - Front Casing Assembly 16
Fig. 13 - Casing Assembly 17
Fig. 14 - Control Panel Configuration 18
Fig. 15 - Control Panel Operation 18
Fig. 16 - Cable/Capillary Tube Routing 20
Page
Fig. 17 - Fitting Thermometer into Flue 20
- Fitting the Burner 20
- Connections 21
- Single Phase Installation 21
Fig. 18 - Boiler & Burner Power Supply 21
Fig. 18A - Boiler & Burner Single Phase
Supply 21
- Three Phase Installation 21
- Volt Free Contacts 21
- Connecting the Gas Supply 21
- Connecting the Oil Supply 22
- Connecting the Water System 22
Section 5
- Commissioning Check List 23
- Contravention of Regulations 23
- Boiler Commissioning 23
- Safety Requirements 24
- Emergency Instructions 24
- Pre-Commissioning Dry Run 24
- Soundness Testing 24
- Commissioning Live Run 24
- Additional Checks 25
- Fault Finding 25
- Overheat Operation 25
- Burner Lockout 25
- Boiler Maintenance 26
- Cleaning Flue Surfaces 26
- Natural Gas/LPG Fired Boilers 26
- Class ‘D’ & ‘C2’ Fired Boilers 26
- Sludge Gas 26
- Boiler Ancillaries 26
- Boiler Controls 26
- Safety Interlocks 26
Section 6
Fig. 19 - Boiler Wiring Diagram 27
- Wiring Diagram – Legend 28
Fig. 20 - Pump Overrun Pipe Thermostat 28
Section 7
- NXR3 Boiler Parts List 29
Fig. 21 - Boiler Components 30
Fig. 22 - Casing Components 32
Fig. 23 - Instrument Panel Components 34

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 1
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3 PAGE 1
Fig. 1 – General Data and Dimensions
Table 1 – Boiler Dimensions
NXR3 Model 34 35 36 37 38 39
A mm 995 1165 1335 1505 1675 1845
B mm 900 1070 1240 1410 1580 1750
∅D mm 180 200
Water Connections F&R 2½” BSP Screwed Flanges (PN6)
Table 2 – Combustion Chamber Data
Model 34 35 36 37 38 39
Mean Diameter mm 474
Cross Sectional Area m
2
0.176
Length (X) mm 625 795 965 1135 1305 1475
Volume m
3
0.11 0.14 0.17 0.2 0.23 0.26
Surface Area m
2
1.11 1.36 1.61 1.87 2.12 2.37
Resistance mbar 0.25 0.54 0.95 1.32 2 2.52
Flue Gas Temperature (Gross) °C 170 160
Percentage CO
2
OIL % 13
GAS % 9.5
Flow
1010
Drain 1 1/2" BSP Return
110
815
450 402
X
DØ
B
A
145
75
520
606
1180
1396
800
Clean
out Hole
2" BSP (FRONT VIEW) (SIDE VIEW) (REAR VIEW)
Flow
1010
Drain 1 1/2" BSP Return
110
815
450 402
X
DØ
B
A
145
75
520
606
1180
1396
800
Clean
out Hole
2" BSP (FRONT VIEW) (SIDE VIEW) (REAR VIEW)

SECTION 1 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 2 NXR3
Table 3 – Technical Data
Model NXR 34 35 36 37 38 39
Number of Sections 4 5 6 7 8 9
CE Number 0085AQ0751
Output kW 90 130 170 210 250 290
1 Fuel Consumption GAS m
3
/hr 10.04 14.5 18.95 23.51 28.06 32.62
OIL Lit/hr 9.97 14.39 18.8 23.33 27.84 32.37
Input (Gross) GAS
OIL kW 107.7 155.5 203.2 252.1 300.9 349.8
Input (Net) GAS
OIL kW 97 140 183 227 271 315
Maximum Design Pressure Bar 6 BAR – ALL MODELS
2 Minimum Operating Pressure Bar 1 BAR – ALL MODELS
3 Nominal Flue Connection Size mm 180 mm Ø 200mm Ø
4 Flue Gas Volume GAS m
3
/hr
OIL m
3
/hr 126 182 237 294 351 409
Flue Draught Requirements 0-4 mm.w.g. – ALL MODELS
5 High Level Natural Ventilation to BS 6644 cm
2
194 280 366 454 542 630
5 Low Level Natural Ventilation to BS 6644 cm
2
388 560 732 908 1084 1260
6 Mechanical Inlet to BS 6644 m
3
/sec 0.075 0.108 0.142 0.176 0.210 0.245
7 Water Connection Size (Flow & Return) 2 ½” BSP Screwed Flanges – ALL MODELS
8 Water Flow at 11°C ∆t lit/sec 1.95 2.81 3.68 4.55 5.41 6.28
Min water flow at 20°C ∆t lit/sec 1.07 1.55 2.02 2.5 2.98 3.45
8 Hydraulic resistance at 11°C ∆t kPa 0.9 1.7 2.8 3.9 5.8 9.3
9 Cold feed size to BS 6644 Minimum Bore mm 25 32
9 Open Vent size to BS 6644 Minimum Bore mm 32 40
9 Safety Valve Size to BS 6644 Nominal Bore mm 19 25
Maximum Flow Temperature °C 90°C – ALL MODELS
10 Minimum Return Temperature (Direct
Compensation) °C 55°C – ALL MODELS
Limit Thermostat Setting °C 110°C – ALL MODELS
11 Dry Weight Kg 612 730 848 966 1068 1184
Water Content kg 112 136 160 184 208 232
Power Requirements (Boiler Control Circuit) 230V 1Ph 50Hz, Fused 6.3A – ALL MODELS
12 Natural Gas Supply Pressure Max
Min 25 mbar 17.0 mbar
35 Second Oil Supply Pressure Max
Min 0.69 mbar 0 bar
See page 3 for explanatory notes Conversion table on inside back cover.

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 1
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3 PAGE 3
1. FUEL CONSUMPTION
Gas fuel consumption is based on natural gas with a gross calorific value of 38.6 MJ/m
3
. The gas rate
should be corrected for the meter supply pressure particularly on high pressure supplies to prevent
overfiring.
Fuel oil consumption is based on Class D (35 second) gas oil with a calorific value of 58.24 MJ/lit and a
density of 0.855 kg/lit, Kerosene (Class C2) has a calorific value of 53.22 MJ/lit and a density of 0.795
kg/lit.
2. MINIMUM OPERATING PRESSURE
This is the minimum operating pressure of the boilers with pumps operating (NOT static pressure). The
requirements of the Health & Safety Executive guidance note PM5 regarding maximum operating
temperatures should be observed.
3. BOILER FLUE CONNECTION
This is the nominal flue size of the flue connection spigot, for dimensional details of the flue connection
spigot see Fig. 1. Actual flue size required to achieve correct draught and operation under all running
conditions may need to be increased.
4. FLUE GAS VOLUME
Flue gas volumes are given at STP (standard temperature and pressure [15°C and 1013.25 mbar]).
Typical flue gas temperatures are given in Table 2.
5. NATURAL VENTILATION
The sizes indicated are free grille areas and are based on a single boiler installation.
6. MECHANICAL VENTILATION
The volume given is for a single boiler installation.
7. CONNECTION SIZES
The boiler water connections are 2 ½” BSP screwed flange PN6. Also supplied 2 ½” welded flanges.
8. WATER FLOW RATES
Water flow rates are given for boiler flow and return water temperature differences of 11°C.
9. COLD FEED/ OPEN VENT/ SAFETY VALVE SIZES
Sizes indicated are minimum sizes for single boiler installations.
10. MINIMUM RETURN TEMPERATURE
If system return temperatures below 55°C are required the contact the Potterton Commercial Technical
Department.
11. WEIGHT
The dry weight is exclusive of the burner and gas train. Each section measures approximately 1100mm
(high) ×606mm (wide) ×180mm (deep) and weighs 106kg (inter), 110kg (front), 125kg (rear).
ANY PERSON OR PERSONS MOVING OR LIFTING SHOULD BE TRAINED IN MANUAL HANDLING
TECHNIQUES AND IF NECESSARY USE SUITABLE LIFTING EQUIPMENT TO REDUCE THE RISK OF
INJURY TO THEMSELVES OR OTHER PEOPLE.
12. Some burners may require higher than 17.0 mbar inlet pressure, please see relevant burner card for details,
or contact the Commercial Technical Office.

SECTION 1 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 4 NXR3
CLEARANCES
The minimum boiler room clearances for access, erection and maintenance are given in Fig. 2 and Fig. 3, the
dimensions are minimum values. There is no minimum clearance above the boiler, however, it is recommended
that clearance is left above the top of the instrument panel to facilitate its removal. At the front of the boiler allow as
a minimum the A dimension, this is to allow access to the combustion chamber for maintenance and servicing. For
P dimension please refer to relevant burner card.
Fig. 2 – Boiler Clearances
Minimum Clearance(Front)
Nu-Way Oil Nu-Way Gas Riello Oil Riello gas EOGB Oil EOGB Gas
Model A (mm) A (mm) A (mm) A (mm) A (mm) A (mm)
34 900 900 900 900 900 972
35 1070 1070 1070 1070 1070 1070
36 1240 1240 1240 1240 1240 1240
37 1410 1410 1410 1410 1410 1410
38 1580 1580 1580 1580 1580 1580
39 1750 1750 1750 1750 1750 1750
Fig. 3 – Boiler Footprint/Base Details
Flat Plate – 6 mm thick
(Not supplied by Potterton)
Boiler Size
C
L
34
750
900
35
920
1070
36
1090
1240
37
1260
1410
38
1430
1580
39
1600
1750
No special plinth is required for
this boiler, a simple dry base is
sufficient. Boiler footprint and
base clearance details are given
in Fig. 3.
Provision must be made to allow
free movement of the boiler on
its base.
600
500 min
P + 200
P
A
200
75
150
C
L
520
800
FRONT

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 2
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR 3 PAGE 5
GENERAL
This boiler is NOT SUITABLE for installation in a
normally occupied area (i.e. kitchen).
A LIFETIME GUARANTEE is available on this boiler
please refer to our standard terms and conditions for
details.
The Potterton NXR3 is a cast iron sectional boiler
available in outputs from 90kW (4-section model) to
290kW (9-section model). The heat transfer surfaces
of the NXR3 have been specially designed to
maximise the boiler efficiency and the large
combustion chamber capacity ensures
environmentally sound combustion reducing CO and
NOx emissions. Specially designed and prewired
control panels allow full boiler control and flow and
return manifolds have facilities to fit sensor pockets for
boiler management systems.
The NXR3 is suitable for running at variable low
temperatures under direct compensated control.
The boiler has match tested package burners,
available for Natural Gas, LPG, 35 Second & 28
Second Oil. Dual Fuel options are also available.
The NXR3 is suitable for use on fully pumped open
vented systems or a sealed system with a maximum
design pressure of 6-bar (87 p.s.i.) and a minimum of
1-bar (14.5 p.s.i.).
The NXR3 boiler is of the overpressure type with 5-
pass reverse flame design. The first two passes are in
the combustion chamber with the other three in the
convection tubes where the turbulence to achieve
high heat transfer is generated by the extended
surface area achieving efficiencies of 93% (net), 84%
(gross).
The NXR3 is constructed with BS1452 Grade 220
cast iron heat exchanger, constructed in accordance
with EN303.1. The boiler package meets gas and oil
requirements of M&E36 and the burners EN676.
The waterway sections are joined by cast taper
nipples and secured with tie rods. The combustion
chamber joints are sealed by heat resistant cord.
The powder coated mild steel casings have a 50mm
fibre insulation in the casing plus a 50mm fibre wrap
around the castings, thus reducing fuel consumption
and emissions.
The NXR3 is supplied unassembled, assembly tools
are provided and a list of the tools is given in Section
4.
STANDARD SUPPLY
•Unassembled cast iron sections (number
dependent on boiler output).
•Smoke box, optimising baffles, flueway door,
combustion chamber door, burner adaptor plate,
flanged flow and return connections.
•Boiler wrap round insulation
•Insulated casing
•Cleaning brush
•Flow manifold complete with sensor pocket, ¾”
screw socket and plug
•Eco control panel
CONTROLS
The NXR3 range is supplied as standard with an
integral control panel which is fitted with hours run
meters, flue thermometer, on/off, control and high/low
thermostats, limit thermostat, water thermostat, reset
button, high temperature warning light, mains on/off
light and fuse. Two volt free remote status contacts
and two hours run meters are included.
OPTIONAL EXTRAS
•3 phase burners
•Additional volt free contacts
•Fully closing air dampers on burner
•Sequence Control Options
SHIPPING - PACKAGING
The boiler package is delivered unassembled on two
pallets with the burner separately either in a carton or
on a pallet.
Pallet 1
Unassembled sections and door.
Pallet 2
Casing pack, boiler accessories, boiler fittings, tie
rods, baffles, flow and return turrets, control panel.
See Section 7 for breakdown of contents.
It is recommended that Potterton Commercial
Division’s trained engineers should carry out erection
and commissioning, as this will make valid the
LIFETIME GUARANTEE. See back page of this
manual for service office addresses
.

SECTION 2 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 6 NXR3
INSTALLATION
Before starting work a risk assessment should be
carried out in the boiler house and its access to
determine and ensure a safe installation and working
environment.
Any person installing or working on the boiler must be
qualified and competent, and in the case of gas fired
boilers attention is drawn to the mandatory
requirement of C.O.R.G.I registration and relevant
ACS qualifications, they must also be electrically
competent and adhere to the IEE regulations.
Manual Handling – Any person or persons moving or
lifting the boiler or any part of it, should be trained in
manual handling techniques and if necessary use
suitable lifting equipment to reduce the risk of injury to
themselves or other people.
The installation should comply with relevant British
Standard specifications, codes of practice and current
building regulations, together with any special regional
requirements of the local authorities, gas undertaking
and insurance company. All electrical wiring must
comply with the IEE regulations for the Electrical
Equipment of Buildings.
The installation of the boiler must be in accordance
with the relevant requirements of: -
•Health & Safety at Work Act 1974
•Building Regulations 2006
•Electricity at Work Regulations 1989
•Management of H&S at Work Regulations 1992
•Manual Handling Regulations 1992
•Model Water Bye-Laws 1986
•BS 7671: 1992 – Requirements for Electrical
Installations, IEE Wiring Regulations 16
th
Edition
•BS 6644: 2005 – Installation of Gas Fired Hot
Water Boilers for Inputs between 60kW and 2MW
•BS 7074: 1989 – Part 2 – Application, Selection &
Installation of Expansion Vessels & Ancillary
Equipment for Sealed Water Systems
•BS 6880: 1988 – Code of Practice for Low
Temperature Hot water Systems
•BS 779: 1989 – Cast Iron Boilers for Central
Heating & Indirect Hot Water Supply (Rated
Output 44kW and Above)
•CP342.2 – Centralised Hot Water Supply
•Gas Safety (Installation & Use) Regulations 2002
•IM/11 Flues for Commercial & Industrial Gas Fired
Boilers & Air Heaters
•IGE/UP/1 – Soundness Testing & Purging
Procedure for Non-domestic Installations
•IGE/UP/2 – Gas Installation Pipework, Boosters &
Compressors for Industrial & Commercial
Premises
•BS EN 303.1 & 303
Manufacturers notes must not be taken in any way as
overriding statutory obligations.
BOILER SITING & BASE
The boiler should be sited in accordance with BS
6644: 2005. This includes considerations for
protecting the boiler from damage, air for combustion,
clearances for service and access, temperatures,
noise levels, the disposal of boiler water and the
effects of flooding of the boiler house or seepage from
a roof top boilerhouse. See Fig. 3 for required boiler
clearances for service and access.
A level non-combustible floor capable of supporting
the weight of the boiler filled with water, see Table 3,
together with any additional weight bearing down on
the base from connections, burner, etc, must be
provided. This should be of an adequate height above
the floor so as to be raised in case of flooding, but
also low enough to allow ease of erection. Typically a
50mm concrete plinth with an area equal to that of the
plan of the boiler is adequate in most cases.
For certain special installations a sound proof plinth
may be necessary and a metal plinth resting on anti-
vibration pads is recommended in these instances.
Consideration should also be given to fitting steel
strips beneath the boiler feet for boiler base
protection, see Fig. 3 for base details.
The boiler has a water-cooled base and no special
insulation is required. When preparing a site,
reference should be made to Local Authorities and
Building regulations 2006.
L.P.G boilers should not be installed in
basements/below ground or in a well.

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 3
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3 PAGE 7
VENTILATION
Safe, efficient and trouble free operation of
conventionally flued boilers is vitally dependent on the
provision of an adequate supply of fresh air to the
room in which the appliance is installed. Account
must also be taken of any other fuel burning appliance
existing or to be fitted when designing the ventilation
and combustion air systems.
IMPORTANT: The use of an extractor fan in the
same room as the boiler (or in an adjacent room in
communication) can, in certain conditions,
adversely affect the safe operation of the boiler
and therefore must be avoided.
Further guidance on ventilation for gas appliances is
provided by BS 6644: 2005. For oil see relevant
Standard.
FLUE
To ensure safe and satisfactory operation the chimney
system, which may be individual or common in the
case of modular boiler installations, shall be capable
of the complete evacuation of combustion products at
all times. The effective height of the chimney
terminal(s) above the boiler(s) flue outlet(s) shall
ensure sufficient buoyancy to overcome the
resistance of the bends, tees and runs of the flue pipe
involved and shall terminate in a down draught free
zone. The number of bends used should be kept to a
minimum and runs of flue pipe less than 45° to the
horizontal should be avoided in order to comply with
the recommendations made in BS 6644: 2005 and
British Gas publication IM/11 "Flues for Commercial
and Industrial Gas Fired Boilers and Air Heaters".
The third edition of the 1956 Clean Air Act
Memorandum and the Building Regulations should be
strictly observed and approval obtained where
applicable, combustion chamber details are given in
section 1.
The flue system must be designed to work specifically
to remove the products of combustion.
IMPORTANT: 90° square bends must not be used
on the flue system, including the boiler flue
spigot, a straight length followed by an "easy
sweep" or lobster back bend should be used.
FLUE SIZE CONSIDERATIONS
Nominal flue connection sizes are given in Table 3,
these sizes refer to the boiler flue connection spigot.
The actual size of the flue system will depend on
individual site applications. Below are general
considerations on sizing flue systems.
Horizontal Flue Runs
Horizontal flue runs are not recommended particularly
over 3m in length, where these are unavoidable
advice should be sought from a flue system specialist.
Common Flue Systems
Where multiple boilers are installed on a common flue
system then the flue system should be designed to
ensure the correct operation of the flue on varying
load conditions. In particular that the appliance flue
draught is within the operating parameter under full
load and partial load conditions. For safe and reliable
operation of the boiler plant it is recommended that
the variance in flue draught available at each
appliance under full and part load operation is
designed to a minimum.
(It is essential that the services of a specialist flue
system manufacturer are sought for the design of
common flue systems).
For further information regarding ventilation and
flueing see relevant British Standard publication
BS6644: 2005.
THE ABOVE RECOMMENDATIONS ARE FOR
GENERAL GUIDANCE ONLY. POTTERTON
COMMERCIAL DIVISION CANNOT ACCEPT
RESPONSIBILITY FOR FLUE SYSTEM DESIGNS
BASED ON THE ABOVE RECOMMENDATIONS.
WATER CIRCULATION SYSTEMS
The water circulation system should be indirect and
installed in accordance with the relevant parts of
British Standards Codes of Practice CP342.2 and BS
6644: 2005.
The maximum and minimum design temperature
differential across the boiler should be 20°C and 10°C
and the boiler should be prevented from operating
with flow rates giving a temperature difference across
the boiler greater than 25°C based on the full boiler
output.

SECTION 3 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 8 NXR3
Boilers operating under constant flow conditions can
be more accurately controlled and are not subject to
excessive temperature stresses.
The boilers MUST NOT be fired under any
circumstances with less than the minimum water flow.
On systems with variable flow rates due to flow
reducing devices, ie. TRVs, zone valves, etc, or where
the minimum heat demand, ie. summer domestic hot
water load, does not achieve the minimum boiler flow
rate then consideration shall be given to incorporating
a primary loop system.
It is recommended that the system is designed to give
a constant boiler flow rate.
BOILER PROTECTION
The provision of pump overrun by a time delay relay
or a thermostat situated in the flow pipe close to the
boiler is essential to remove residual heat from the
boiler, see Fig. 21, section 6.
Unions and isolating valves should be fitted to the flow
and return manifolds so that the boiler can be isolated
from the system if the need arises. Your legal
obligations must be adhered to. (i.e. appropriate
safety valves must be fitted).
SYSTEM WATER QUALITY
High efficiency boiler systems require the water
quality of the system water to be controlled by the use
of inhibitors to maintain a neutral Ph and inhibit
corrosion. Additionally the water system should be
free of leaks to prevent raw water make up which will
dilute any inhibitors, promote corrosion and form lime
scale.
Existing Systems
On existing systems where boilers are being replaced
due to failure then the cause should be investigated
before installing new boilers. This can normally be
achieved by cutting open a failed boiler section and
examination for system debris or contamination.
Lime scale is a positive indicator of continuous system
water make up due to water loss. Evidence of
magnetite (black sludge) in the system and the
formation of gas in radiators causing air locking is a
positive indicator of corrosion.
Where an old system shows evidence of
contamination then system cleaning should be carried
out before installation of new boilers. The heating
system should be chemically flushed to remove any
lime scale or corrosion and a corrosion and lime scale
inhibitor added. Lime scale descalers if incorrectly
used could cause any remaining system debris to
continue to breakdown and contaminate the new
boiler causing boiler failure.
Advice on system cleaning and suitable products
should be sought from specialist suppliers of system
cleaners such as Fernox or Sentinel.
It is important to note that corrosion inhibitor can only
be used in an attempt to prevent corrosion from
occurring, where a system has an existing corrosion
problem, inhibitors will be ineffective and the system
requires cleaning.
On existing systems where comprehensive descaling
and desludging cannot be carried out then
consideration should be given to separating the new
boiler system from the existing system pipe work by
the use of plate heat exchangers.
New Systems
New pipe work systems should be thoroughly flushed
with a suitable cleaning agent to remove debris and
flux residues before filling. The system water should
be dosed with a suitable corrosion and lime scale
inhibitor.
System Water Monitoring
The system water should be monitored as part of a
maintenance programme to ensure the following:-
Raw water make up is not occurring.
Corrosion and lime scale Inhibitors are still active
Water Ph is below Ph 8.5 other wise on systems with
aluminium content, component failures may occur.
SEALED SYSTEMS
General
Potterton Commercial boilers are suitable for use on
sealed systems designed in accordance with BS
6644: 2005 and BS 6880 Part 2. In addition,
reference should be made to the Health & Safety
Executive guidance note PM5 "Automatically
Controlled Steam & Hot Water Boilers".

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 4
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3 PAGE 9
BOILER ERECTION
A lifetime guarantee is available on this boiler when
erection and commissioning is carried out by the
Potterton Commercial service department and the
system meets with our recommendations. Please
refer to our standard terms and conditions for further
details.
Risk Assessment
Before starting work a risk assessment should be
carried out on the boiler house and its access to
determine and ensure a safe installation and working
environment.
Regardless of the type of activity being assessed, the
principles of risk assessments are the same. The
basic steps are: -
•Classify Activity
•Identify Hazards
•Identify Existing Control Measures
•Determine Risk
•Assess Acceptability of Risk
•Prepare a Control Plan
•Implement Plan
•Review Plan
•Record Results
Manual Handling
Any person or persons moving or lifting the boiler or
any part of the boiler, should be trained in manual
handling techniques and if necessary use suitable
lifting equipment to reduce the risk of injury to
themselves and other people.
Personal Protective Equipment
When undertaking any work you must comply with the
Personal Protective Equipment Regulations 1992.
Confined Spaces
A “confined space” as defined in the Health & Safety
Confined Spaces Regulations 1997 ‘ means any
place, including any chamber, tank, vat, silo, pit,
trench, pipe, sewer, flue, well or other similar space in
which, by virtue of its enclosed nature, there arises a
reasonably foreseeable specified risk.
Precautions should be taken in all areas where by
virtue of its even partially enclosed nature, pose a
reasonably foreseeable specified risk.
Electrical Safety
Working on appliances can be broken down into two
main systems of work.
1) Safe systems of work are adapted for all boiler
maintenance and repair work undertaken on site.
2) The work undertaken does not affect the electrical
safety of the appliance. In particular the earth
connected to the buildings fixed electrical
installation.
In the case of (1) above electrical work should only be
undertaken once the boiler has been isolated from the
electricity supply and confirmed electrically dead. If
this is impractical then suitable precautions must be
undertaken to prevent injury.
In the case of (2) above checks are specified to
identify any abnormality in the electricity supply to the
boiler as well as to confirm that the boiler electrical
connections are reinstated correctly where it is
necessary to disconnect or reconnect any internal
wiring within the boiler.
If it is necessary to disconnect and reconnect the
appliance from the site electrical installation other than
means of a plug and socket then additional checks
shall be undertaken by an approved engineer to check
the earth loop impedance in accordance with IEE
regulations.
Always carry out preliminary electrical safety checks.
All appliances and central heating systems must be
provided with their own means of isolation for safety
purposes especially during installation and
maintenance.
Packaging Details
A detailed breakdown of the contents of the packages
is given in section 7.
Preparation
Preparatory to installation of the boiler a check must
be made to ensure that suitable facilities are available
for off-loading of the individual waterway sections and
conveying them to the boiler room. Each waterway
section weighs approximately 110 kg and measures
1100mm x 606mm x 180mm. Ensure all manual
handling techniques are followed.
Particular attention must be paid to ensuring
cleanliness of the boiler room and waterway sections,
dust or moisture may result in
imperfect adhesion of
the sealants which are applied during the erection of
the waterways. All tapped holes should be degreased
before making connections.

SECTION 4 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 10 NXR3
C.O.S.H.H
During the erection procedure there are a number of
items which are subject to the Control Of Substances
Hazardous to Health (C.O.S.H.H) Regulations, and
may require specialist personal protective equipment
(P.P.E) beyond what is normally required. Listed
below are the items subject to the C.O.S.H.H
regulations and the recommended precautions that
should be taken. For a full breakdown of any
substances listed below, please contact the
Commercial Technical Department.
1. Refractory Ceramic Fibre Insulation Block –
Wear gloves, overalls and safety glasses. In the
case of an irritation rinse the affected area with
water and wash gently. In the case of eye contact,
flush abundantly with water. If irritation persists
seek medical advice.
2. Refractory Ceramic Fibre Insulation Blanket –
Wear gloves, overalls and safety glasses. In the
case of an irritation rinse the affected area with
water and wash gently. In the case of eye contact,
flush abundantly with water. If irritation persists
seek medical advice.
3. Nipple Sealing Paste – Wear gloves and
overalls. In the case of an irritation rinse the
affected area with water and wash gently. In the
case of eye contact, flush abundantly with water.
If irritation persists seek medical advice.
4. Sealing Rope - Wear gloves and overalls. In the
case of an irritation rinse the affected area with
water and wash gently. In the case of eye contact,
flush abundantly with water. If irritation persists
seek medical advice.
Potterton Commercial Customer
Erection/Assembly Check List
The items listed below have been put together as a
guide to what actions should be completed before the
erection/assembly of a boiler takes place.
I. Site access available for persons carrying out
the proposed work.
II. Site managers/personnel aware that work will
be taking place.
III. Risk assessments carried out on possible
risks that may effect the persons carrying out
the proposed work.
IV. Sections and fittings boxes should be
positioned adjacent to the plinth(s) within the
boiler house prior to persons carrying out the
proposed work attending site. If this is unable
to be done notice prior to attending site
should be given.
V. When boilers are to be stripped and rebuilt,
labour and transport should be provided for
moving the sections from the delivery point to
the final erection point. If this is unable to be
provided notice prior to attending site should
be given.
VI. Sections/casing, etc, should be kept in a
clean and dry area prior to erection/assembly.
VII. Water should be available.
VIII. A drain off area should be available.
IX. Power should be available.
X. A site representative should be available at all
times.
XI. Clear instructions supplied to the persons
carrying out the proposed work regarding
positioning the boiler.
XII. Fire evacuation procedures, facilities
availability, specific health and safety
information, etc, should be provided.
Items VII to X are essential if boilers require pressure
testing.

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 4
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3 PAGE 11
BOILER ERECTION
SECTION ASSEMBLY
The boiler sections are not self-supporting until the
boiler block is fully assembled. The sections are
connected using a nipple system. To ensure a sound
water tight fit the nipple sealing paste provided must
be used. Assembly tools are provided for assembling
the sections.
IMPORTANT: Ensure the boiler is adequately
supported especially when pulling up sections.
The Manual Handling Regulations should be
followed.
Erect the Boilers as follows:-
1. Open the boiler fittings box.
2. Clean the nipples using a solvent cleaner
removing all traces of protective coating (not
supplied), ensuring all guidelines are followed.
3. Clean both the top and bottom nipple ports of all
sections with a solvent cleaner and ensure that
they are rust free, dirt-free and burr free, if
necessary clean with emery cloth.
4. Stand the rear section up and ensure that it is
supported securely. Ensure correct manual
handling techniques are used.
5. Position the wooden block provided under the
centre of the bottom nipple port of the rear section
(see Fig. 4).
6. Clean the sealing cord groove on the upright
section with a solvent cleaner and a wire brush,
ensuring any rust or burrs are removed.
7. Starting from the centre of the top nipple port,
position the sealing cord without stretching it in
the groove around the rear section. Cut to length
using due care and attention.
8. Coat a nipple with the sealing paste provided and
position in the top nipple port. Repeat for the
bottom nipple port. Tap both nipples slightly into
the nipple ports using a mallet to ensure nipples
are not damaged.
Ensure that the nipples are correctly aligned
as an out of line nipple can cause the section
to crack when it is pulled up.
Fig. 4 – Section Assembly Showing Installation of Sealing Cord, Nipples & Final Sealing Cord Tightness
Sealing Cord
Meeting Point
Place the Cord in the
Sealing Cord Groove
Tightening of the
Sealing Cord
Section Orientation
Marking
Wooden Block (provided)
Section Orientation
Marking
Outside
Separation Lug

SECTION 4 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 12 NXR3
9. Ensure that the intermediate section is correctly
aligned (see Fig. 4). Offer up the first intermediate
section and mount onto the rear section nipples
using the wooden block for support. Using a
mallet alternately on the top and bottom nipple
ports knock the section into place. Ensure all
manual handling techniques are adhered too.
Ensure that the intermediate section is aligned
parallel to the rear section.
10. Assemble the top and bottom pulling up bars (see
Fig. 5 and Fig. 6) provided through the top and
bottom nipple ports and pull up the sections until
metal to metal contact is made in the combustion
chamber and flueways.
The sections should be pulled up evenly half a
turn at a time applying equal pressure to top
and bottom pulling up bars. Section alignment
should be checked throughout the process.
The sealing cord will be pulled up into place and
protrude slightly from the joint (see Fig. 4).
11. Loosen and remove the pulling up bars.
12. Assemble the other sections (one by one) in the
same way, while moving the wooden blocks
alternately as you go towards the front. Ensure all
manual handling techniques are adhered too.
Note: If it was necessary to dismantle one of
the boiler sections, and to avoid damaging the
sealing groove. It is imperative, when
dismantling the sections to place a chisel on
the separating lugs as shown in Fig. 4.
Note: Orientation arrow top right hand side of
section (looking from front). The arrow must point
towards the front of the boiler and all arrows must
face the same way.
Boiler Assembly Pulling Up Bars
Assemble the pulling up bars as shown in Fig. 5 and
position through the top and bottom nipple ports.
Ensure that the plate and bar are positioned centrally
through the boiler. Ensure that the threads and
bearing surfaces are greased before and during use.
Pull up ONLY one section at a time.
A set of pulling up bars is provided as follows:-
•2 bars: 1260 mm long (4-6 section)
1625 mm long (7-8 section)
1800 mm long (9 section).
•4 plates
•4 small washers
•4 large washers
•2 short nuts
•2 long nuts
Orientation
Arrow
Pulling Up
Bar
Rear Section
Inter Section
Spanner
Plate
2 Washers
Short
Nut
Threaded Bar
Fig.5 – Section Orientation
Long Nut

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 4
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3 PAGE 13
Fig. 6 – Boiler Fittings Assembly
1 Front Section 14 Distributor (6&7 section) 25 Sight Glass Flange
2 Intermediate Section 14a Distributor (8&9 section) 26 Sight Glass & Seal
3 Rear Section 15 Flow and Return Manifold 27 Door Seal (Ø16)
4 Nipple (Ø89) 16 Drain Valve 28 Burner Plate
5 Sealing Cord (Ø7) 17 Sensor Pocket (100mm length) 29 Burner Plate Gasket
6 Tie Rod 18 Upper Baffle 30 Cleaning Door
7 Reducer 19 Flue Hood (180mm outlet) 31 Internal Insulation
8 Sensor Pocket (200mm length) 19a Flue Hood (200mm outlet) 32 External Insulation
9 Door Hinge 20 Flueway Hatch (left) 33 Section Insulation Blanket
9a Door Hinge 20a Flueway Hatch (right) 39 Cleaning Brush
10 Door Guide 21 Sealing Rope 40 Bag of Screws
11 Door Pin 22 Chamber Door 42 2” Blanking Plug
12 Welding Flange 23 Internal Insulation
13 Flange Gasket 24 External Insulation

SECTION 4 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 14 NXR3
Fittings Assembly
1. Position Boiler – Position the boiler block in its
final resting position on the boiler plinth (if
applicable). Ensure all manual handling
techniques are adhered too, also ensure that a
risk assessment has been carried out.
2. Flow & Return Studs – Fit the 8 off 12 x 65 studs
to the flow and return ports in the rear section of
the boiler.
3. Distributor – (Fig. 6 – items 13, 14 and 14a). Fit
the rubber gasket to the distributor and insert the
distributor into the rear port. (4 and 5 section
models do not require a distributor).
4. Sensor Pocket – (Fig. 6 – items 7 and 8). Fit the
2” - ½” reducer and phial pocket into the 2”
tapping in the top of the door.
5. Front Drain Plug – (Fig. 6 – item 42). Fit the 2”
plug to the tapping in the bottom of the front
section.
6. Rear Drain Plug – Fit the 1 ½” plug to the tapping
in the bottom of the rear section.
7. Flow Turret – (Fig. 6 – item 17). Fit sensor pocket
and ¾” plug into turret tapings. (Fig. 6 – items 12
– 17). Fit turret to flow connection using rubber
gasket to make seal.
8. Return Turret – Repeat the above operations for
the return turret.
9. Connections – (Fig. 6 – item 12). Two off 2 ½”
BSP screwed flanges PN6, with two off rubber
gaskets are provided to make flow and return
connections.
10. Hydraulic Testing – Blank off all connections
then fill the boiler slowly ensuring that all the air is
vented and the boiler is completely full of water.
Proceed to 9 bar to prove soundness. This facility
is available through our Service Offices.
11. Flue Box – (Fig. 6 – items 19 to 19a). Screw the
short thread of the four off M8 x 40mm studs into
tappings in the upper part of the rear section.
Check the sealing braid is in place on the flue
hood (Fig. 6 – items 19 to 21). Fit the flue hood to
the studs on the rear section and secure. (The
flueway cleaning door [Fig. 6 – items 20 and 20a]
are pre-fitted to the flue hood).
12. Flue – Connect the flue to the boiler, ensuring that
the requirements of BS 6644: 1991 – Installation
of Gas Fired Hot Water Boilers for Inputs Between
60 kW – 2MW are adhered to.
13. Baffles - Insert the baffles into the upper flueways
(Fig. 7).
Fig. 7 - Baffles
14. Front Section Hinges – (Fig. 8) – Screw the
short thread of the eight off M8 x 40mm studs into
the front section. Mount the hinges (1 screw
HM10 x 30mm + 1 nut HM10 + 2 washers L10 for
each guide). The door guide is located opposite
the hinges, in the upper part.
Fig. 8 – Door Hinge & Guide Assembly
15. Door Hinges – (Fig. 6 – items 9 and 9a) Fit the
hinges to the combustion chamber door and
flueway door using two off M12 washers for each
hinge.
Upper
Baffles
Stud M10x90
Guide
Stud M10x90
Screw T
H M10x30
Stud M10x90
Guide
Screw TH M10x30
Stud M10x90
Stud M10x90
Hinge
Screw TH M10x30
Screw TH M10x30
Hinge
Stud M10x90
Stud M10x90
Hinge
Screw TH M10x30
Screw TH M10x30
Hinge
Stud M10x90

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 4
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3 PAGE 15
16. Combustion Chamber Door – (Fig. 6 – items 27,
30, 31 and 32). Fit the door sealing braid in place
then mount the combustion chamber door. (Fig. 6
– item 11). Secure using the door hinge pins and
fix in place over the door guides securing with
HM10 nuts and HM10 x 30 bolts. Ensure all
manual handling techniques are adhered to.
17. Flueway Door – (Fig. 6 – items 23 to 29). Fit the
door sealing braid in place then mount the flueway
door (Fig. 6 – item 11). Secure using the door
hinge pins and fix in place over the door guides
securing with HM10 nuts and HM10 x 30 bolts.
Ensure all manual handling techniques are
adhered to.
18. Burner Adaptor Plate – (Fig. 6 – items 28 and
29). Fit the burner adaptor plate using the four off
HM12 x 35 nuts and M12 washers to the
combustion chamber door.
19. Burner – After fitting the burner adaptor plate to
the burner door, it is essential to cut out the
burner door insulation to the diameter of the
burner draft tube, to allow the burner to pass
through without damaging the door insulation.
INSULATION & CASING FRAME ASSEMBLY
1. Lower Rear Insulation – Screw the hexagonal
spacers onto the rear section’s three spacer pads
and partly screw in a TH M5 x 10 screw to each
spacer. Fit the 100mm thick insulation onto the
rear section. (There are three holes in the
insulation to allow it to fit over the spacers).
2. Lower Rear Casing – (Fig. 13 – item 51). Fit the
lower rear casing over the three spacers and
tighten the three screws.
3. Bottom Insulation – (Fig. 9). Place the bottom
insulation blanket underneath the boiler and fold
around the bottom tie rods to secure. Ensure that
all personal protective equipment is worn.
Fig. 9 - Insulation Position
4. Body Insulation Blanket – (Fig. 9). Wrap the
body insulation blanket around the boiler. Push
the ends of the tie rods through the slots in the
insulation blanket. Tuck the bottom of the blanket
under the bottom of the boiler. NB: For 38 & 39
models the body insulation blanket is supplied
in two parts, to be positioned side by side, the
large part towards the front.
5. Casing Frame Cross Members – (Fig. 13 – item
53). Fit the casing frame cross members to the
front and rear. They locate on the ends of the tie
rods, secure with nuts and washers. Note that the
front cross member has a black coloured
protection clip (to protect burner wiring which
passes close by) which should be at the front right
hand side of the boiler – irrespective of the
handing of the combustion chamber door.
6. Casing Frame Support Rail – (Fig. 13 – items
54 and 55). Fit the left and right casing frame
support rails to each side of the boiler (Fig. 10).
Ensure that they are correctly orientated. Secure
the casing frame support rails to the casing frame
cross members with nuts washers and 4 off HM8
x 16 bolts.
Fig. 10 – Casing Support Frame
Top Insulation
Blanket
Rear Insulation
Blanket
Side Insulation
Blanket
Bottom Insulation
Blanket
Eight off
screws
Front of boiler
Secure with
bolt & washer
Casing frame
cross member
Casing frame
support rail
Rear of
boiler
Black
protection clip
Tie rods

SECTION 4 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 16 NXR3
7. Top Front Casing Support Bracket – (Fig. 13 –
item 64). Fit the top front casing support bracket
(with the fold looking forward and upward) to the
front of the casing frame cross member and
secure with two screws.
8. Top Insulation Blanket – Place the top insulation
blanket on the casing support frame. The slits in
the insulation should be at the front.
9. Casing Brackets – (Fig. 13 – item 52). Fit the two
off casing brackets to the lower front of the boiler.
CASING ASSEMBLY
Note: The boiler casing is not load bearing.
1. Front Side Panels (Black) – (Fig. 13 – 57 and
58). Hook the front side panels over the casing
frame support rails and lower front casing
brackets with the clip brackets towards the rear.
Clip the brackets onto the bottom tie rods to
secure. Screw into place to the casing support
frame rails and to the lower front casing brackets.
2. Middle Side Panels (Models 37, 38 & 39 only) –
(Fig. 13 – item 63). Hook the middle side panels
over the casing frame support rails with the clip
brackets towards the rear, locating the panel onto
the pin on the front side panel. Clip the brackets
onto the bottom tie rods to secure.
3. Rear Side Panels – Hook the rear side panels
over the casing frame support rails and the lower
rear panel, locating the panel onto the pin on the
front/middle side panel. Screw into place the
casing support frame rails and lower rear panel.
4. Upper Rear Panel – (Fig. 13 – item 63). Slide
upper rear panel into position and locate lugs in
holes in rear of side panels. Push down to secure.
5. Front Top & Instrument Panel – (SEE
CONTROL PANEL FOR CONTROL PANEL
ASSEMBLY). Secure instrument panel to front
top panel via four off screws. Feed stat phials,
burner cables and earth wire through the slit in the
top insulation then position front top/control panel
inside casing support frame. Push forward to
secure.
6. Middle Top (Models 37, 38 & 39 only) – Place in
between casing support frame rails. Push forward
towards front top to secure.
7. Rear Top Panel – Position on casing frame
support rails and push forward. Fix in position to
upper rear panel with two off screws.
8. Lower Mask – (Fig. 13 – item 56). Hook the lower
mask over the casing brackets.
9. Lower Front Panels (black) – (Fig. 13 – items 69
and 70). Locate lower left and right front panels on
lugs on side panels and bracket onto lower mask.
Push down to secure.
10. Upper Front Panel – (Fig. 13 – item 68). Position
in locating holes on lower front panels. The upper
front panel is secured by two magnets onto the
side panels.
Fig. 11 – Casing Side Panel Assembly
No. of Sections 4 5 6 7 8 9
Front A
300
Middle B
N/A 510
Rear C
514 684 854 514 684 854
Fig. 12 – Front Casing Assembly
Front Middle
Rear Front Rear
C
B
A B
A

POTTERTON COMMERCIAL PRODUCTS DIVISION SECTION 4
INSTALLATION, OPERATION & MAINTENANCE MANUAL
NXR3 PAGE 17
Fig. 13 – Casing Assembly
50 Rear Spacer 62 Side Casing – Middle (37/38/39 only)
51 Lower Rear Panel 63 Rear casing – Top panel
52 Casing Support Brackets 64 Top Panel Front Support Strip
53 Cross Member 65 Top Casing – Front Panel
54 Right Hand Side Support Rail 66 Top Casing – Rear Panel
55 Left Hand Side Support Rail 67 Top casing – Middle Panel (37/38/39 only)
56 Lower Mask 68 Front Casing – Top Panel
57 Side Casing – Right Hand Front 69 Front Casing – Lower Right
58 Side Casing – Left Hand Front 70 Front casing – Lower Left
59 Side Restraint 71 Bag of Casing Screws/Fixings
60 Side Casing – Right Hand Rear 80 Control Panel
61 Side Casing – Left Hand Rear
71 - Bag of Screws

SECTION 4 POTTERTON COMMERCIAL PRODUCTS DIVISION
INSTALLATION, OPERATION & MAINTENANCE MANUAL
PAGE 18 NXR3
INSTRUMENT PANEL
Fig. 14 - Control Panel Configuration
Fig. 15 - Control Panel Operation
The CE 100 module provides the following functions
-Operation at 1
st
Stage
-Detection of boiler overheat, ionisation probe fault
-Ability to restrict max boiler temperature using jumper at back of module
-Indication of the operation mode of the boiler
-Operation of 2
nd
Stage operation
Pump Switch (Not Used)
Pump Indicator
Light
Boiler Temperature
Control Thermostat
Green Indicator Light
Showing 1st Stage Run
(If l
ight flashes indication of
overheat fault)
2
nd
Stage Thermostat
2
nd
Stage
Indicator Light
CE 100
1
2
3
4
6
5
7
8
9
10
11
12
13
14
15
16
1 Control thermostat 9 2
nd
stage time delay
2 1
st
Stage indication light 10 1
st
stage hours run meter
3 Boiler thermometer 11 2
nd
stage indication
4 Overheat thermostat 12 On/off switch
5 Reset button 13 6.3 amp fuse
6 Overheat indicator 14 Over-ride button for safety checks
7 Lockout indicator 15 Over-ride thermostat
8 Flue gas thermometer 16 Mains supply indicator
NXR3/4 Control Panel