Hamworthy FERNDOWN Manual

IMPORTANT NOTE
THESE INSTRUCTIONS MUST BE READ
AND UNDERSTOOD BEFORE INSTALLING,
COMMISSIONING, OPERATING OR
SERVICING EQUIPMENT
Ferndown
Room Sealed Water Heater
Installation, Commissioning
and Servicing Instructions

Technical Enquiries 01202 662527/662528
To supplement the detailed technical brochures, technical advice on the application and use of products in the
Hamworthy Heating range is available from our technical team in Poole and our accredited agents.
Site Assembly 01202 662555
Hamworthy offer a service of site assembly for many of our products in instances where plant room area is restricted.
Using our trained staff we offer a higher quality of build and assurance of a boiler built and tested by the manufacturer.
Commissioning 01202 662555
Commissioning of equipment by our own engineers, accredited agents or specialist sub – contractors will ensure the
equipment is operating safely and efficiently.
Maintenance Agreements 01202 662555
Regular routine servicing of equipment by Hamworthy service engineers inspects the safety and integrity of the plant,
reducing the risk of failure and improving performance and efficiency. Maintenance agreements enable our customers to
plan and budget more efficiently.
Breakdown service, repair, replacement 01202 662555
Hamworthy provide a rapid response breakdown, repair or replacement service through head office at Poole and accred-
ited agents throughout the UK.
Spare Parts 01202 662525
A comprehensive spare parts service is operated from our factory in Poole, providing replacement parts for both current
and discontinued products. Delivery of parts and components is normally from stock within seven days. However, a next
day delivery service is available for breakdowns and emergencies.
Customer Services

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Ferndown
Room Sealed Water Heater
Installation, Commissioning
and Servicing Instructions
NOTE: THESE INSTRUCTIONS SHOULD BE READ AND UNDERSTOOD BEFORE
ATTEMPTING TO INSTALL, COMMISSION OR OPERATE THIS UNIT
THE FERNDOWN WATER HEATER IS INTENDED FOR USE AS A COMMERCIAL
APPLIANCE & CAN BE OPERATED AS EITHER ROOM SEALED OR OPEN FLUE.
THIS APPLIANCE IS FOR USE ON GROUP H NATURAL GAS (2ND FAMILY)I2H OR LPG-
PROPANE (3RD FAMILY)I3P. PLEASE ENSURE RELEVANT INFORMATION REQUIRED
WITHIN DOCUMENT IS FOUND RELATING TO SPECIFIC GAS TO BE FIRED BEFORE
FIRING APPLIANCE.
THIS APPLIANCE COMPLIES WITH ALL RELEVANT EUROPEAN DIRECTIVES.
EC TYPE CERTIFICATE No. (GAD) EC 87/02/27, (BED) BE-87/01/02
PRODUCT IDENTIFICATION No 87BN27
PUBLICATION NO. 500001111
ISSUE ‘C’
May 2003
i

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
CONTENTS
PAGE
INDEX ................................................................................ iii
1.0 INTRODUCTION ..............................................................................…... 1
2.0 TECHNICAL DATA ..........................................................................…… 1
3.0 GENERAL REQUIREMENTS ..........................................................…… 5
3.1 Related Documents
3.2 Feed Water Quality
3.3 Adequate Water Flow
3.4 Time Clock Control
3.5 Minimum System Water Pressure
4.0 LOCATION .......................................................................................…… 6
5.0 GAS SUPPLY...................................................................................……. 6
5.1 Service Pipes
5.2 Meters
5.3 Gas Supply Pipes
5.4 Boosted Supplies
5.5 Boiler House Control Valve
5.6 Boiler Gas System Leak Check
6.0 FLUE SYSTEM ................................................................................…… 6
6.1 General Requirements
6.2 Condense Drain
6.3 Design Waste Gas Volume and Temperature
6.4 Maximum Length of Flue Duct
6.5 Disconnection
6.6 Flue Discharge
6.7 Surface Temperatures
6.8 Flue System Location
7.0 AIR SUPPLY ....................................................................................…… 13
7.1 Air Supply by Natural Ventilation (Open Flue)
7.2 Air Supply by Natural Ventilation (Room Sealed)
7.3 Air Supply by Mechanical Ventilation (Open Flue)
8.0 WATER CIRCULATION SYSTEM ...................................................…… 13
8.1 General
8.2 Pressure Relief Valve (Safety Valve)
8.3 Open Vent Pipe and Cold Feed Pipe
8.4 Altitude Gauge (Water Pressure Gauge)
8.5 Thermometer
8.6 Drain Valves
8.7 Circulating Pump
8.8 Controls
8.9 Unvented Pressurised Systems
8.10 Boiler Control Scheme
ii

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
PAGE
9.0 ELECTRICAL SUPPLY ...................................................................... 15
9.1 Electrical Supply Connections
9.2 Indication Signals & Volt Free Contacts
9.3 Cable Installation
10.0 BOILER ASSEMBLY AND INSTALLATION..................................... 15
10.1 General
10.2 Assembling the Appliance
10.3 Connection of the Boiler Module to the Flue System
10.4 Water Connections
10.5 Condense Trap Connection
10.6 Gas Connection
10.7 Fitting the Front Cover and Panels
11.0 COMMISSIONING AND TESTING ...............................................….. 21
11.1 Electrical Installation
11.2 Gas Installation
11.3 Water Circulation System
11.4 Commissioning the Boiler
11.5 Appliance Checks Prior to Lighting
11.6 External Controls
11.7 User’s Instructions
12.0 FAULT FINDING............................................................................…. 25
12.1 1 Safety Features Summary
12.1.2 Fault Finding Procedures
12.1.3 Possible Causes of Boiler Lockout
13.0 SERVICING.....................................................................................…….. 30
14.0 REPLACEMENT OF FAILED COMPONENTS...............................……… 31
15.0 RECOMMENDED SPARES............................................................………. 33
APPENDIX ‘A’ - INFORMATION RELATING TO PROPANE FIRING.....…….. 34
FIGURES PAGE
Figure 1.1 Appliance Installation.................………………………………....... 2
Figure 2.1 Appliance Dimensions & Clearances ................................... 3
Figure 2.2 Performance & General Data Information………….................... 4
Figure 6.1.1 Horizontal Balanced Flue (C13)................................................... 8
Figure 6.1.2 Vertical Balanced Flue (C33)....................................................... 9
Figure 6.1.3 Separate Intake & Discharge Ducts (C53)................................... 10
Figure 6.1.4 Intake from Ventilated Plant Room & Discharge via
Horizontal / Vertical Flue (C53)................................... 11
Figure 6.1.5 Flue Terminal Positions 12
Figure 6.4 Flue Resistance ........................................................................... 7
Figure 7.2 Minimum Air Vent Requirements – Compartment Installation.…. 13
Figure 7.3 Mechanical Ventilation Flow Rates.............................................. 13
Figure 8.10 Site Wiring Diagram....................................................... 16
Figure 9.1.1 Wiring Schematic (Auxiliary Control Panel).......................... 16
Figure 9.1.2 Wiring Schematic (Main Control Panel)..…………………...... ....................................17
Figure 10.3.1.1 Connection of Flue System (Concentric Ducts Horizontal).......... 18
Figure 10.3.1.2 Flue Support Cradle…………………………………. 18
Figure 10.3.2 Connection of Flue System (Concentric Ducts Vertical)............ 19
Figure 10.3.3 Connection of Flue System (Separate Ducts).............................. 19
iii

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
PAGE
Figure 11.1 Appliance Layout.......................................................................... 22
Figure 11.2 Gas Valve / Venturi Layout................................................ ……….. 23
Figure 11.3.1 Thermostatic Mixing Valve Settings...........................................… 21
Figure 11.5 Instrumentation Set Up for Initial Lighting and Offset Adjustment. 23
Figure 11.5.4 Fan Speed Vs Boiler Input ...................................…. 25
Figure 12.1 General Fault Finding………..................................................…… 26
Figure 12.2 General Fault Finding………..................................................…… 27
Figure 12.3 General Fault Finding………..................................................…… 28
Figure 12.4 General Fault Finding………..................................................…… 29
Figure 13.2 Position of Probes on Burner Assembly...................................…. 30
Figure 2.2 Performance & General Data Information – LPG Propane..… 34
iv

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
1.0 INTRODUCTION
1.1 This appliance must be installed by a competent
person holding 'CORGI' registration or equivalent. All
installations MUST conform to the relevant Gas Safety
and Building Regulations. Health & Safety requirements
must also be taken into account when installing any
equipment. Failure to comply with the above may lead
to prosecution.
1.2 The appliance is intended for use on Group H
Natural Gas (2nd Family) and LPG-Propane (3rd
Family). The information relating to propane firing is to
be found in Appendix ‘A’. The appliance MUST NOT
use gas other than that for which it was designed and
adjusted.
1.3 The Ferndown is a high efficiency, gas fired, fully
modulating, room sealed instantaneous water heater
with the included option of connecting to and supplying
central heating systems. For performance data refer to
Figure 2.2.
1.3.1 The burner fitted to the Ferndown is of the fan
assisted pre-mix type. Operation is initiated by a full
sequence ignition control that incorporates a Hot
Surface Ignition system and rectification supervision of
the flame across the range of outputs.
1.3.2 The appliance is designed for direct connection to
a room sealed or conventional flue system - HHL
supply. The Technical Data for the various flue
arrangements is given in Section 6. No draught diverter
is fitted to the boiler nor is a fixed diverter required in the
flue system. However a draught stabiliser is
recommended for some installations.
1.3.3 The Ferndown is intended as a single stand alone
unit not suitable for modular application supplying
domestic hot water and central heating within
Commercial / Industrial premises only.
1.3.4 The Ferndown is fitted with an integral circulator
pump suitably sized to ensure that minimum water rates
are maintained through the low water content primary
heat exchanger.
1.3.5 The Ferndown uses a brazed plate heat
exchanger for DHW generation. To ensure continuous
and reliable operation, refer to section 3.2.2 regarding
water conditioning.
1.4 The Ferndown is suitable for direct connection to
domestic hot water supplies and to fully pumped un-
vented (pressurised) heating systems. Care must be
taken to ensure all extra safety requirements are
satisfied and that the relevant interlocks will shut the
Ferndown off should a high or low pressure fault occur.
The Ferndown primary loop circuit is fitted with a
pressure switch, factory set at 0.5 bar which shuts the
appliance down should the primary water pressure fall
below the factory set threshold.
Note: The Ferndown is not suitable for direct connection
to gravity circulation systems.
When connecting to pressurised central heating circuits
the pressurisation unit must also incorporate a low level
water switch which protects the water pumps, and will
directly or indirectly shut down the boiler plant should a
low water condition occur. Consideration should also be
given to the maximum working pressure of the
appliance as given in Section 2: TECHNICAL DATA.
Consult Hamworthy Heating Technical Department for
help or assistance if in doubt.
1.5 N.B. For space heating applications, the
Ferndown has a constant flow (non-adjustable)
temperature of 80°C, therefore thermostatic
radiator valves should be used to control the
temperature.
2.0 TECHNICAL DATA
2.1 The Ferndown data plate giving details of model
and serial number is located on the inner boiler casing.
Overall dimensions are shown in Figure 2.1.
2.2 General Information and Technical Data relating
to Natural Gas is shown in Figure 2.2.
Technical data relating to propane firing can be
found in Appendix ‘A’.
2.3 Screw threads: All screw threads used in the
Ferndown range of boilers conform to the following:-
ISO 7/1 or ISO 228/1 for pipe threads where applicable.
ISO 262 for all general screw threads.
1

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Figure 1.1 Appliance Installation (Typical)
2
HEATING
SYSTEM
CONNECTIONS
THERMAL STORE
BOILER
MODULE
THERMOSTATIC
MIXING VALVE
DOUBLE CHECK VALVE
DRAIN VALVE
TEMPORARY FILL CONNECTION (Remove immediately after filling).
SAFETY VALVE
DRAIN
PRESSURE
GAUGE
COLD FEED
DHW OUT
FERNDOWN WATER HEATER INTERNAL LAYOUT
PLATE HEAT EXCHANGER
ISOLATING VALVE
ISOLATING VALVE
PORTLAND PRESSURIZATION UNIT
MAINS WATER SUPPLY
DRAIN
VALVE
SYSTEM EXPANSION
VESSEL
AUTOMATIC AIR VENT
AUTOMATIC AIR VENT
FERNDOWN
WATER
HEATER
ISOLATING VALVE
ISOLATING VALVE
HEATING CIRCUIT
CIRCULATION PUMP
ALTERNATE POSITION
CIRCULATION
PUMP
LOCKSHIELD VALVE
LOCKSHIELD VALVE
PRESSURE & TEMPERATURE GAUGES
P T
OPTIONAL PUMPED
RE-CIRCULATION
DHW CIRCUIT
NOTE FOR SPACE HEATING APPLICATIONS, THE FERNDOWN HAS A CONSTANT FLOW (UNADJUSTABLE) TEMPERATURE OF 80°C, THEREFORE THERMOSTATIC RADIATOR VALVES SHOULD BE USED TO CONTROL THE TEMPERATURE.

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Figure 2.1 Appliance Dimensions/Clearances
3
150
720 150
150
200 - CENTRE
LINE FLUE
185
460 600
85
200
320
VIEW ON UNDERSIDE
DHW CONNECTIONS
510
450 COVER
REMOVAL
CLEARANCE
150
MIN
268
426
511 MAINS WATER IN
DHW OUT
M20 ELECTRIC CONDUIT
M20 ELECTRIC CONDUIT
35
85
185
50
1540
1660
180
VIEW ON
UNDERSIDE
CENTRAL HEATING
CONNECTIONS
536
300
CORE DRILL
150 DIA
290
140

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Figure 2.2 Performance and General Data Information – Natural Gas
GENERAL DATA FERNDOWN
Boiler Input kW (Gross) - maximum 77.7
Boiler Input kW (Nett) - maximum 70.0
Boiler Input kW (Gross) - minimum 15.5
Boiler Input kW (Nett) - minimum 14.0
Space Heating Output kW -minimum 13.6
Space Heating Output kW - maximum 63.7
DHW output (30°C rise) l/min 30.4 (1825 l/h)
DHW output (44°C rise) l/min 20.7 (1244 l/h)
FLUE DATA
Nominal Flue Dia. mm Single pipe = 100, dual concentric
= 80/125 or 100/150
Approx. Flue Gas Temperature °C 140
Approx. Flue Gas Vol. @ 9.0 – 9.5% CO2& NTP(Dry) m3/h 114
Nox corrected (daf) mg/kWh [ppm] 44 [25]
GAS DATA
Nominal Gas Inlet Press. mbar 20
Maximum Gas Inlet Press. mbar 25
Minimum Gas Inlet Press. mbar 12.5
Gas Flow Rate -maximum m3/h 7.4
Gas Inlet Connection Pipe Thread Size Rp¾”
WATER DATA
Water Connections DHW 22mm Copper
Maximum Water Pressure (Primary) bar g 2.5
Maximum Water Pressure (Secondary) bar g 7.0
Water Content (not including pipework) litres 34.0
Shipping Weight (excluding flue) kg 165
ELECTRICAL DATA
Normal Supply Voltage 230V AC 50Hz (300W max.)
Start and Run Current < 1A
Water Connections DHW re-circulation ¾” BSP
Water Connections Central Heating (F&R) 1 ¼ ” BSPT
Circuit Resistance (Primary) bar 0
Circuit Resistance (Secondary) bar 0.5 @ 20 l/min
NOTE ! Boiler outputs based on European test conditions – the maximum δT for the Ferndown boiler is
15°C. Flue gas volumes are based on a flue gas temperature of 0°C at 1013mbar
4

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
3.0 GENERAL REQUIREMENTS
3.1 Related Documents.
Gas Safety Installations and Use Regulations 1994-
(As amended). It is law that all gas appliances are
installed by competent persons, in accordance with the
above regulations. Failure to install appliances correctly
could lead to prosecution. It is in your own interest, and
that of safety, to ensure that this law is complied with.
The installation of the Ferndown MUST be in
accordance with the relevant requirements of the Gas
Safety Regulations, Building Regulations, IEE
Regulations and the bylaws of the local water
undertaking.
The installation should also be in accordance with
any relevant requirements of the local gas region
and local authority and the relevant
recommendations of the following documents :-
British Standards
BS 5440: Part 1: Specification for installation of flues.
Part 2: Specification for installation of ventilation for gas
appliances.
BS 6644: Installation of Gas Fired Hot Water Boilers -
60 kW to 2MW.
BS 6700: Design, installation, testing and maintenance
of services supplying water for domestic use.
BS 6880:Part 1, 2 & 3: Code of practice for low
temperature hot water heating systems of output
greater than 45 kW.
BS 7074:Part 1: Application, selection and installation
of expansion vessels and ancillary equipment for sealed
water systems. Part 2: Code of practice for low and
medium temperature hot water systems.
CP 342: Centralised hot water supply. Part 2: Buildings
other than individual dwellings.
I. Gas E. Publications
IGE/UP/1 Soundness testing and purging of
industrial and commercial gas installations.
IGE/UP/1A Soundness testing and direct purging of
small low pressure industrial and commercial natural
gas installations.
IGE/UP/2 Gas installation pipework, boosters and
compressors in industrial and commercial premises.
IGE/UP/10 Installation of gas appliances in industrial
and commercial premises Pt 1 flued appliances.
CIBSE Publications:- "CIBSE Guide"
It is impractical in this document to specify all relevant
information, but the following extracts from the above
references are emphasised since failure to comply with
these requirements will almost certainly result in an
unsatisfactory installation.
3.2 Feed Water Quality
3.2.1 Primary Water
If the boiler feed water has a high degree of
hardness, it is recommended that the water be
treated to prevent precipitation of scale or sludge in
the boiler water passageways. Details of additives
can be obtained from any reliable manufacturer of
water treatment products or the local water
authority.
It should be noted however, that even if the boiler water
is of average hardness, not requiring treatment,
subsequent draining of the system for repair or constant
make-up water due to an undetected leak will cause
additional deposits and gradual build-up of scale. It is
essential therefore, that leaks are attended to promptly
and draining is kept to an absolute minimum.
It is recommended that the system be flushed out at
least twice before any water treatment is added. If any
doubt exists regarding the internal cleanliness of an old
system, consideration should be given to the fitting of a
coarse filter in the return pipework to the boilers.
3.2.2 Domestic Water
To ensure the continued and reliable operation
of this product, a traditional salt exchange water
softener must be suitably sized and fitted
upstream of the cold water inlet unless
otherwise advised by the local water authority.
Failure to comply with this requirement will
result in the invalidation of the product warranty.
3.3 Adequate Water Flow
The Ferndown is fitted with an integral circulator pump
suitably sized to ensure that minimum water rates are
maintained through the low water content primary heat
exchanger.
When connecting to central heating systems care
should be taken in the initial design and layout having
due regard for adequate water flow through the
appliance and the influence of the system controls.
Note: When connecting to a central heating system
operating at 80/70°C the effect of the Ferndown on
system pressure losses can be considered negligible as
the integral circulator pump is sized to overcome the
resistance of the heat exchanger and therefore does not
add to or reduce system resistance.
5

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
3.4 Time Clock Control
The integral primary loop circulating pump is
provided with a five minute over-run after the boiler
has ceased firing to prevent localised overheating
and progressive calcium deposition.
NOTE! Time clocks must not interrupt live, neutral or
earth connections, see Section 9.0: ELECTRICAL
SUPPLY for details. See Figures 8.10, 9.1.1 and 9.1.2
for wiring details.
3.5 Minimum System Water Pressure
It is recommended that a minimum cold fill pressure of 1
bar is set during the initial cold fill.
When connecting the appliance to central heating
systems, reference should be made to Section 8.9.
4.0 LOCATION
4.1 (See Figures 2.1. & 2.2. for dimensions /clearances
and weights.) The location chosen for the Ferndown
MUST permit the provision of a satisfactory flue system
and an adequate air supply. The location must also
provide adequate space for servicing and air circulation
around the appliance. This includes any electrical
trunking laid along the floor and to the appliance.
The must be installed on a non combustible flat and
level surface capable of supporting the weight of the
appliance when full of water and any additional ancillary
equipment.
Any combustible material adjacent to the Ferndown
and the flue system must be so placed or shielded
to ensure that its temperature does not exceed 65°
C.
Further details regarding appliance location are given in
BS 6644. & BS 5440 part 2.
5.0 GAS SUPPLY
5.1 Service Pipes
The local gas region must be consulted at the
installation planning stage in order to establish the
availability of an adequate supply of gas. An existing
service pipe must not be used without prior consultation
with the local gas region.
5.2 Meters
A new gas meter will be connected to the service pipe
by the local gas region, or a local gas region contractor.
An existing meter should be checked, preferably by the
gas region, to ensure that it is adequate to deal with the
rate of gas supply required.
5.3 Gas Supply Pipes
Supply pipes must be fitted in accordance with BS 6891
or IGE/UP/2. Pipework from the meter to the boiler must
be of adequate size. Do not use pipes of a smaller size
than the boiler gas connection. The complete installation
must be purged and tested for soundness as described
in BS 6891 or IGE/UP/1 & IGE/UP/1A as appropriate.
5.4 Boosted Supplies
Where it is necessary to employ a gas pressure
booster, the controls must include a low pressure cut-off
switch at the booster inlet. The local gas region must be
consulted before a gas pressure booster is fitted.
5.5 Boiler House Control Valve
A manual valve for boiler house isolation shall be fitted
in the gas supply line. It shall be clearly identified and
readily accessible for operation, preferably by an exit.
5.6 Boiler Gas System Leak Check
The incoming mains gas supply must be capable of
supplying gas to the appliance at the required pressure
and volume, under all firing conditions. An isolating
valve and union is supplied for each appliance and
is accessible at the bottom of the casing.
Although the boiler module receives a gas leak check
prior to leaving the factory, transport and installation
may cause disturbance to unions, fittings and assem-
blies etc. During commissioning, a further test for
soundness should be carried out on the boiler gas pipe-
work and components.
Note:- Main Gas Supply Pressure -
Nat Gas - 20mbar
Propane - 37mbar
6.0 FLUE SYSTEM
Detailed recommendations for flue systems are given in
BS 6644, BS 5440, IGE/UP/10.
All flue discharges for plant exceeding 150kW out-
put must comply with the Third edition of the 1956
Clean Air Act Memorandum.
The following notes are intended to give general
guidance only.
For allowable terminal positions refer to figure 6.1.5.
6

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
6.1 Flue System General Requirements
The Hamworthy Ferndown is designed for use with the
following flue systems supplied by Hamworthy - see
Figures 6.1.1, 6.1.2, 6.1.3 & 6.1.4:
80/125mm concentric room sealed, balanced flue
system for rear through the wall discharge.
100/150mm concentric, room sealed, balanced flue
system for remote discharge, horizontal or vertical –
maximum length 7m.
100mm separate air and flue ducts, room sealed,
balanced flue system for remote discharge – maximum
length 10m.
100mm flue duct, for connection to an open flue
(chimney) system – maximum length 10m.
Flue systems should be designed with reference to BS
5440 part 1, IGE/UP/10, and Third Edition of the 1956
Clean Air Act Memorandum.
Flue installations can be configured to suit a number of
applications, see Figures 6.1.1, 6.1.2, 6.1.3 & 6.1.4: but
must comply with one of the following options:
Room Sealed.
Type C13: Horizontal balanced flue. – Fig 6.1.1.
Type C33: Vertical balanced flue. – Fig 6.1.2.
Type C53: Separate intake and discharge ducts
terminating in different pressure zones. – Fig 6.1.3.
Open Flue.
Type B23: Intake from ventilated plant room and
discharge via horizontal/vertical flue. – Fig 6.1.4.
WARNING
The Sherborne boiler is a High Efficiency/
Condensing boiler and in certain conditions
‘pluming’ will be visible from the flue terminal.
Should pluming be a concern, the flue system
design should discharge at high level.
Care should be taken to ensure that the flue is
installed such that any condensation is continuously
drained back to the boiler or any resultant low points
in the flue system. Horizontal flue runs should be
kept to a minimum and must be inclined at 2°
upwards in the direction of the exhaust gas flow. All
joints should be such that any condensation is
directed back down the slope.
6.2 Condense Drain
The boiler module is provided with a condense drain
suitable for connection to 22mm plastic waste pipe
(not supplied), which must be connected to a
tundish (not supplied).
Discharge piping from a tundish should be of a
synthetic material due to the mild acidity of the
condensate (pH 3-5), with all discharge piping
having a minimum fall of 30mm/m away from the
boiler. Consideration should be given to possible
freezing of condense water traps and pipework. This
must be avoided at all times by routing pipework
within the building, where possible.
6.3 Design Waste Gas Volume and Temperature
Figure 6.4 Flue Resistance
Component Length
m
Straight tube ø100mm per m 1
45° bend ø100mm 2.25
90° bend ø100mm 4.10
Concentric straight tube ø80/125mm per m 1
Concentric straight tube ø100/150mm per m 1
Concentric 45° bend ø100/150mm 1.30
Concentric 90° bend ø100/150mm 2.20
Equivalent tube lengths.
6.5 Disconnection
Each Ferndown is fitted with a telescopic appliance
connector, enabling the boiler to be disconnected from
the flue system.
NOTE! The flue system must be self supporting and
not present a risk to people in or around the building.
See Section 13: SERVICING for further information.
6.6 Flue Discharge
The flue system must ensure safe and efficient
operation of the Ferndown to which it is attached,
protect the combustion process from wind effects and
disperse the products of combustion to the external air.
The flue must terminate in a freely exposed position and
be so situated as to prevent the products of combustion
entering any opening in a building in accordance with
BS 5440 part 1, IGE/UP/10.
When the application requires the flue discharge to
terminate below 2 m above ground level, the use of a
terminal guard is required.
6.4 Maximum Length of Flue Duct.
For Ferndown installations the maximum allowable
linear equivalent length of straight smooth bore tube
for both (air supply and flue discharge) twin duct,
and concentric systems is approximately 10m and
7m respectively. This dimension relates to the
distance between the boiler and the discharge
terminal. The table below nominates the equivalent
length of flue tube. Components can be combined in
any order provided that the total equivalent length of
flue does not exceed the maximum. Note: if the
maximum stated lengths of flue are exceeded the
boiler will not achieve maximum output.
7

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Figure 6.1.1. - Horizontal Balanced Flue
7m max
Flue type C13
Ref Horizontal terminal
007 Assembly Ø80/125
Wall plate Ø125
014
Ref
028
Ref
Ø100/150
90° Concentric Bend
Ref
027
45° Concentric Bend
Ø100/150
Ø100/150 Adjustable
Ø100/150 x 1m long
029
030
Ref Concentric Flue
Ref Concentric Flue
Ref Horizontal terminal
Assembly Ø100/150031
Eccentric Adaptor
Enlarged detail showing cut
Ø80/100
Ø80 Flue
Support Bend
023
Ref
Ref
001
Flue make up piece
Ø100 x 250 long
020
Ref
Ø150 x 100
Ref
043
Concentric Adaptor
section through concentric adaptor
Note: If the terminal is fitted vertically
within 2m of areas accessible to people an
appropriate terminal guard having a minimun
dimension of 250 x 250 x 220 should be fitted.
8

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Figure 6.1.2. - Vertical Balanced Flue
7m max
section through concentric adaptor
Enlarged detail showing cut
100 x 250 long
Concentric Adaptor
Flue make up piece
Eccentric Adaptor
Flue type C33
150 x 100
Ø80/100
Ø80 Flue
Support Bend
Ref
020
Ref
043
023
Ref
Ref
001
Ref
029
Ref
030
Ref
033
027
Ref
028
Ref
038
Ref
044
Ref
Ref
032
Flat Roof Flashing
Adjustable Flashing
Concentric Flue
Concentric Flue
Ø100/150 x 1m long
Ø100/150 Adjustable
Assembly Ø100/150
Wall Clamp Ø150
Vertical Terminal
90° Concentric Bend
45° Concentric Bend
Ø100/150
Ø100/150
Ø150 Flue
Ø150 Flue
9

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Figure 6.1.3. - Separate Intake and Discharge Ducts
Flue type C53
Enlarged detail A
Horizontal Inlet
Terminal Ø100
Ref
024
Ref
Ref
022
Ref
Ref
Ref
019
018
020
021
90° Bend
1000 long Ø100
1000 long Ø100
Single Flue
1000 long Ø100
250 long Ø100
500 long Ø100
Single Flue
Single Flue
Eccentric Adaptor
Ref
023
Ref
001 Ø80 Flue
Support Bend
Outlet = 0.4m min
10m max
Ø80/100
Outlet = 10m max Inlet = 10m max
Single Flue
Single Flue
Single Flue
250 long Ø100
1000 long Ø100
500 long Ø100
Wall Clamp Ø100
Horizontal Flue
Terminal Ø100
1000 long Ø100
45° Bend
1000 long Ø100
90° Bend
Eccentric Adaptor
Wall Clamp ø100
Flat Roof Flashing
Adjustable Flashing
Support Bend
Vertical terminal
Ref
017
021
022
Ref
020
Ref
Ref Ref
025
018
019
Ref
Ref
Ø80/100
Ø100 flue
Ø100 flue
Ø80 Flue
Ø100 Flue
023
Ref
017
Ref
Ref
040
Ref
039
001
Ref
026
Ref
Inlet = 0.4m min
10m max
Detail A
Note: If the flue terminal is fitted vertically
within 2m of areas accessible to people an
appropriate terminal guard having a
minimum dimension of 250 x 250 x 220
should be fitted.
Reference to BS5440 should be made for
determination of acceptable terminal
location.
Terminals for the supply of combustion
air and for the evacuation of combustion
products not be installed on
opposite walls of a building.
must
10

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Figure 6.1.4. - Intake from Ventilated Plant Room and Discharge via Horizontal/Vertical Flue
Adjustable Flashing
Ø100 flue040
Ref
039
Ref
Ø100 flue
Flat Roof Flashing
Ref
021
Ref
020
Single Flue
Single Flue
500 long Ø100
250 long Ø100
Ref
022 1000 long Ø100
Single Flue
Ref
026
Vertical terminal
Ø100 Flue
Ref
023 Ø80/100
Eccentric Adaptor
Ref
017
Wall Clamp Ø100
Ref
022
021
Ref
020
Ref
Single Flue
500 long Ø100
1000 long Ø100
Single Flue
Single Flue
250 long Ø100
Ref
017
Wall Clamp Ø100
Ref
019 1000 long
45° Bend Ø100
Ref
018 1000 long
90° Bend Ø100
flue system if suitable
Modular header or existing
Enlarged detail (typical B23)
Eccentric Adaptor
Flue type B23
80/100
80 Flue
Support Bend
023
Ref
Ref
001
Air Inlet
80 Flue
Ref
048
Note: If installing a horizontal flue terminal that is fitted vertically within
2m of areas accessible to people an appropriate terminal guard having
a minimum dimension of 250 x 250 x 150 should be fitted.
11

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
Figure 6.1.5. - Flue Terminal Positions
Dimensions Terminal Position Balanced Flue
Room Sealed
Open Flue
A Directly below an opening, air brick, opening window etc 300 300
B Above an opening, air brick, opening window etc 300 300
C Horizontally to an opening, air brick, opening window etc 300 300
D Below gutters, soil pipes or drain pipes 75 75
E Below eaves 200 200
F Below balconies or car port roof 200 200
G From a vertical drain pipe or soil pipe 150 150
H From an internal or external corner 300 200
I Above ground roof or balcony level 300 300
J From a surface facing the terminal 600 600
K From a terminal facing the terminal 1200 1200
L From an opening in the car port (e.g. door, window) into
the dwelling
1200 1200
M Vertically from a terminal on the same wall 1500 1500
N Horizontally from a terminal on the same wall 300 300
O From the wall on which the terminal is mounted N/A 50
P From a vertical structure on the roof N/A N/A
Q Above intersection with roof N/A 150
Note: The above values represent minimum required dimensions.
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HAMWORTHY HEATING LTD FERNDOWN 500001111/C
6.7 Surface Temperatures
Combustible materials in the vicinity of the Ferndown
and flue shall not exceed 65°C during boiler operation.
The flue shall not be closer than 50mm to any
combustible material, except where it passes through
such material with a non-combustible sleeve when the
air gap may not be less than 25mm.
6.8 Flue System Location
The flue system must not be placed or fitted where
there is undue risk of accidental damage to the flue pipe
or undue danger to persons in the vicinity. Check that
the flue is clear from any obstruction.
7.0 AIR SUPPLY
Detailed recommendations for air supply and ventilation
requirements are given in BS 6644, and BS 5440:Part
2. The following notes are intended to give general
guidance. In all cases there must be provision for an
adequate supply of air for both combustion where
applicable, and general ventilation, in addition to that
required for any other appliance.
7.1 Air Supply By Natural Ventilation
(Open-flue installation only)
The boiler room must have, or be provided with,
permanent air vents directly to the outside air, at high
level and at low level. For an exposed boiler house, air
vents should be fitted preferably on all four sides, but at
least on two sides. Air vents should have negligible
resistance and must not be sited in any position where
they are likely to be easily blocked or flooded or in any
position adjacent to an extraction system which is
carrying flammable vapour. Grilles or louvres must be
so designed that high velocity air streams do not occur
within the space housing the boiler.
The air supplied for boiler house ventilation shall be
such that the maximum temperatures within the boiler
house shall be as follows:
1) At floor level (or 100mm above floor level) = 25°C.
2) At mid-level (1.5m above floor level) = 32°C.
3) At ceiling level (or 100mm below ceiling level) =
40°C.
Where both low and high level openings are used, the
grilles shall have a total minimum free area of :-
Low Level - (inlet) 550cm2per boiler.
High Level - (outlet) 275cm2per boiler.
7.2 Air Supply (Room-sealed installation)
If the Ferndown is installed as a room-sealed boiler
within a room there is no requirement for the room to
have additional ventilation.
If the Ferndown is installed as a room-sealed boiler
within a cupboard or compartment, the enclosure
shall be provided with both high and low level air vents
sized in accordance with the following.
Figure 7.2 Minimum Air Vent Requirements per
Boiler Installed in a Compartment
Vent position
Room or inter-
nal space
Direct to out-
side air
cm2/boiler cm2/ boiler
High level 700 350
Low level 700 350
Compartment ventilated to:
7.3 Air Supply By Mechanical Ventilation
(Open-flue installation only)
Air supplied to the boiler room by Mechanical means
should be as follows :-
1) Mechanical inlet and mechanical extract can be
utilised providing the design extraction rate does not
exceed one third of the design inlet rate.
2) Mechanical extract ventilation with natural inlet
ventilation MUST NOT be used.
NOTE: For Mechanical ventilation systems an
automatic control should be provided to cut off the gas
supply to the boiler, in the event of failure of air flow in
either inlet or extract fans.
Figure 7.3 Mechanical Ventilation Flow Rates
…. (Open flue installation only)
Forced / in-
duced
Flow rate per 1000kW
total rated heat input (Gross)
Inlet air
(Combustion
ventilation)
Extract air
(ventilation)
m³/s. m³/s.
Volume 0.90 0.60
8.0 WATER CIRCULATION SYSTEM
8.1 General
Recommendations for central heating water circulation
system are given in BS 6644 and CP 342. The following
notes are of particular importance:-
1) In a combined central heating and hot water system,
the circulating pipework not forming part of the useful
heating surface should be insulated to help prevent heat
loss and possible freezing, particularly where pipes are
run through roof spaces and ventilated cavities.
Insulation exposed to the weather should be rendered
waterproof
2) The Ferndown is supplied with two R1¼male flow
and return connections located on the thermal storage
tank. See figure 11.1
3) Valves should be fitted adjacent to the Ferndown to
13

HAMWORTHY HEATING LTD FERNDOWN 500001111/C
enable isolation from the system, however, the
arrangement must comply with the requirements of BS
6644. See Section 10.4 Water Connections.
8.2 Pressure Relief Valve (Safety Valve)
The Ferndown is supplied with a temperature and
pressure relief valve factory fitted and set at 3 bar and
95°C.
8.3 Open Vented Systems
The Ferndown appliance is not suitable for connection
into open vented systems.
8.4 Altitude Gauge (Water Pressure Gauge)
The Ferndown is supplied with a factory fitted pressure
gauge located on the thermal storage tank inside the
plastic cover. If connecting to central heating systems
an additional pressure gauge should be located in a
visible position.
8.5 Thermometer
If connecting the Ferndown into a central heating
system a thermometer complete with pocket should be
fitted in the pipework to indicate water flow temperature.
See Figure 1.1. for typical position.
8.6 Drain Valves
The Ferndown thermal storage tank is provided with a
½” drain valve intended for draining the boiler and tank
only. When connecting to central heating systems
additional drain valves should be located in accessible
positions which permit the draining of the central heating
system as recommended by BS 6644. See Figure 1.1.
for suggested positions.
8.7 Circulating Pump
If connecting the Ferndown into a central heating
system one or more circulating pumps will be required
to circulate water around the heating system. The pump
should be sited to facilitate servicing. When the
Ferndown is used to replace appliances on an existing
system it is important that the existing system be
flushed through twice to remove any loose matter,
which may have accumulated. If in any doubt regarding
the cleanliness of the system, a coarse filter should be
fitted in the return pipework from the central heating
system.
Note that the Ferndown flow temperature is factory set
at 80°C and cannot be adjusted. It is recommended that
the heating system is sized and operated with 80°C flow
and 70°C return. Provided that the system is operated
within these parameters the effect of the Ferndown on
the central heating system pressure losses will be
negligible.
8.8 Controls
8.8.1.1 Temperature Controls
The temperature of the water outflow is factory set at 82°C
and should not be adjusted.
8.8.1.2 Thermostatic Mixing Valves
For space heating applications, the Ferndown has a
constant flow (un-adjustable) temperature of 80°C,
therefore thermostatic radiator valves should be used to
control the temperature.
8.8.2 Frost Protection
The Ferndown is an instantaneous water heater designed
to run continuously resulting in the primary loop circuit
always being at approximately 80°C. If connecting the
Ferndown into a central heating system where elements
of the system are subject to exposure to low temperature
consideration should be given to fitting a frost thermostat
set at approximately 4°C.
8.9 Unvented Systems
See Figure 1.1. for typical layout of an Unvented
(Pressurised) Hot Water System. For system design refer
to BS 7074 Part 2.
In order to correctly size a pressurisation unit for any
heating system certain parameters are required. These
are:-
1) Static height of highest component in system (metres).
2) System volume - if it is not known a general rule of
thumb of 10 litres/kW of installed boiler power can be used.
3) Maximum flow temperature (°C).
4) Maximum system hot working pressure, generally given
in bar gauge.
From the above information Hamworthy Heating can size
the pressurisation unit and also the expansion vessel
required.
Care must be taken in sizing expansion vessels to ensure
maximum acceptance factors are not exceeded. Normally
manufacturers of vessels impose a limit of 0.5. This value
must not be exceeded at any time during the operation of
the boiler, this includes the over pressure condition should
a safety valve lift.
Note: The factory fitted T & P valve is set at 3 bar which
should be taken into consideration when determining
system operating parameters.
8.10 Boiler Control Scheme
Ferndown installations can be operated in fully modulating
mode, controlled from a simple time-clock or BMS system
via a remote stop/start loop. – see Figure 8.10.
The boiler module can be set to run in the hi/lo mode
however this operating scheme is not recommended for
water heating applications.
14