O Potterson CF 20/35 User guide

CF 20/35 CF 35/50
Open Flue Gas Fired Boiler
THIS APPLIANCE IS FOR USE WITH NATURAL GAS ONLY.
Installation and Servicing Instructions
LEAVE THESE INSTRUCTIONS ADJACENT TO THE GAS METER.
Page 1
Page 2
FLAMINGO CF
20/35 G.C. No. 41 .605.59
35/50 G.C. No. 41 .605.60

IMPORTANT
This appliance must be installed by a competent person as stated in the Gas
Safety (Installation and Use) Regulations 1984.
Flamingo boilers are certified by BSI for safety. It is therefore important that no
external devices (e.g., flue dampers, economisers etc.) be directly connected
to theseappliances unless covered by these installation instructions or otherwi
se recommended in writing.
Any direct connection of a control device not approved by Potterton could inva
lidate the BSI certificate and the normal warranty.
LIST OF CONTENTS
Page No .
General
3
Accessories
3
Installation Data
3
Boiler Dimensions
4
Site Requirements
6
Technical Data
7
Installation Instructions
12
Commissioning
16
Servicing Instructions
19
Control Systems, Pipework and Wiring Guide
Supplied in
User’s Instructions
Literature Pack
Page 2
GENERAL - Page 3
Potterton Flamingo Open Flue boilers are automatically controlled, wall-
mounted appliances, using a cast iron heat exchanger and are available in tw
o outputs ranging from5.86-14.65 kW (20,000-
50,000 Btu/h). Refer to TECHNICAL DATA page 8. The boilers which are desi
gned to provide domestic hot water and/or central heating must beused on IN
DIRECT hot water systems only. The cast iron heat exchangers are suitable f

or use on sealed or open vented gravity hot water/pumped central heating sys
tems orfully pumped systems.
ACCESSORIES
The following range of Potterton system controls are also available and further
information will be provided upon request.
Electronic Programmer EP. 2000, E.P. 3000, E.P. 4000.
Programmable Electronic Thermostat PET 1
Thermostatic Radiator Valve PV456 and PH456
Electronic Cylinder Thermostat PTT 1
Electronic Room Thermostat PRT 1
Spring Return Zone Valve PMV2
Spring Return Diverter Valve PMV3
INSTALLATION DATA
The installation of the boiler must be in accordance with the latest relevant req
uirements of the Gas Safety (Installation and Use) Regulations 1984, local buil
ding regulations,current lEE Wiring Regulations and the bye-
laws of the local Water Undertaking.
Detailed recommendations are contained in the following British Standards an
d Codes of Practice.
BS. 6798 1987, BS. 5440 Part 1 1978
BS. 5440 Part 2 1976, BS. 5449 Part 1 1977
BS. 5546 1979, BS. 4814 1979, BS. 6891
BUILDING REGULATIONS
MODEL WATER BYE-LAWS
BRITISH GAS PUBLICATION DM2
GAS SAFETY (INSTALLATION AND USE) REGULATIONS 1984
BUILDING STANDARDS (SCOTLAND) REGULATIONS.
Page 3
INSTALLATION DATA - Page 4
FIG. 1. BOILER DIMENSIONS (mm)

Page 4
INSTALLATION DATA - Page 5
FIG. 2. GENERAL ARRANGEMENT

Page 5

SITE REQUIREMENTS - Page 6
These boilers are not suitable for external installation.
This appliance must not be installed in bathrooms, shower rooms, bedrooms,
bed-
sitting rooms, garages or rooms where highly inflammable materials or vapour
s are likelyto be present. Fitting in toilets or cloakrooms is not recommended b
ut it is permitted, provided the ventilation and combustion air is taken direct fro
m outside.
Where the installation of the boiler will be in an unusual location special proce
dures may be necessary and BS. 6798 1987 gives detailed guidance on this a
spect.
Ensure that the gas supply pipe and meter are large enough for this appliance
and any others that may be run off the same meter. Reference should be ma
de to BS. 6891.
Boiler Mounting Surface
The boiler must be mounted on a flat wall, which may be of combustible mater
ial and must be sufficiently robust to take the weight of the boiler. The require
ments of the localauthorities and the Building Regulations must be adhered to.
IMPORTANT NOTICE: TIMBER FRAMED HOUSES
If the appliance is to be fitted in a timber framed building it should be fitted in a
ccordance with British Gas Publication.
‘Guide for Gas Installations in Timber Framed Housing’. If in doubt, advice mu
st be sought from the local Gas Region of British Gas.
Clearances Around The Boiler
The following minimum clearances must be maintained after installation for co
rrect operation and servicing of the boiler-
610 mm (2 ft) at the front of the boiler:-
5 mm (0.2 in) each side of the boiler
100 mm (4 in) at the top (measured from the top of boiler case)
100 mm (4 in) at the bottom of boiler
Additional clearances may be required to lift the boiler on to the wall.
COMBUSTION AIR AND VENTILATION REQUIREMENTS
General recommendations are given in BS. 5440 Part 2, and the followin
g notes are given as a general guide.

1. Ventilation of Compartments containing Gas Boilers
There should be two permanent air vents, one at low level and one at high lev
el, both communicating either directly with outside air or with a room or space
which is suitablyventilated. Each opening, whether left free or furnished with a
grille, must have a minimum effective area in accordance with TABLE 1.
TABLE 1
Level of Air Vent
Area for Air whethertaken from a Room orOutside.
cm²
cm²
CF 35/50
High
425
68
Low
425
68
CF 20/35
High
245
39
Low
245
39
There must be at least 300mm (12in) clearance between the grille on the front
of the boiler casing and any internal surface of the cupboard to allow for adeq
uate air foroperation of the draught diverter.
Further details for installation of a boiler within a compartment are given in BS.
6798 1987.
2. Ventilation of Rooms containing Gas Boilers
The ventilation of the room containing the boiler shall include air for combustio
n and draught diverter dilution. This applies also when the boiler is sited in a c
ompartment,unless the air vents are both direct to outside.
A permanent air vent shall be provided in an outside wall of the building at eith
er high or low level.
This opening may be:
a) Directly into the room or space containing the boiler or,
b) Via a duct through a wall or roof of the room,
(where such a method is considered British Gas should be consulted), or
c)
Into an adjacent room or space which has an internal permanent air vent of th
e same size to the room containing the boiler. It is undesirable to ventilate via
a kitchen,bathroom or toilet.

The air vent should be sited as far as possible from any extract fan to avoid sh
ort circuiting. To avoid the possibility of freezing water pipes, the vent should n
ot be sited nearpipes.
The minimum effective area of the permanent air vent must be:
CF 35/50 56 cm² 9 in²
CF 20/35 30 cm² 4.9 in²
If the room (e.g. kitchen) from which air is drawn, has an extract fan fitted, the
n the opening size of the permanent air vent should take this into account to e
nsure that theoperation of the boiler flue is not adversely affected when the ex
traction fan is running with all doors and windows closed. This should be chec
ked in accordance with BS.5440 Parts 1 and 2.
3. Grilles and Ducts
Any grille and/or duct should be so sited and of a type not to become easily bl
ocked or flooded and should offer low resistance to air flow.
Page 6
SITE REQUIREMENTS - Page 7
FLUE
A 100mm (4 in) internal diameter flue must be connected to this appliance to e
vacuate the products of combustion from the boiler. The flue connecting socke
t on the boiler isdesigned to accept fluepipe to BS. 567. If a fluepipe to BS. 71
5 is to be used an adaptor must be fitted to the boiler flue connecting socket.
Reference should be made to The Building Regulations and British Standard
5440 Part 1. The following notes have been compiled for your guidance:-
a)
The flue pipe should be at least 25mm from any combustible material, or wher
e passing through a wall, floor or roof, be separated from any combustible mat
erial by a non-
combustible sleeve enclosing an air space of at least 25mm around the flue pi
pe.
b)
Ideally a flue should rise vertically to a termination point which is unaffected by
down draught or wind eddies and is not in a pressure zone. Therefore, for pra
cticalpurposes, the flue should have the shortest run possible; 90º bends shou

ld be avoided. The terminal must be at least above roof edge level and must b
e of a type acceptableto British Gas.
c)
Whever possible there should be at least 2 ft (600mm) of vertical flue from the
boiler flue socket.
NOTE: A split socket should be fitted in this length.
d)
Horizontal runs should be avoided. If a near horizontal length is unavoidable, i
t must be followed by at least twice that length of vertical flue.
e) Wherever possible internal stacks, lined if necessary, should be used.
f) All brick chimneys must be lined with a liner acceptable to British Gas.
g) Where condensation is likely a means of draining must be provided.
h)
If an existing flue is being used, ensure that it has been thoroughly swept befo
re lining or connecting the boiler.
ELECTRICITY SUPPLY
A 240V ~ 50 Hz., single phase electricity supply fused at 3A must be provided
in accordance with the latest edition of the I.E.E. wiring regulations and any ot
her localregulations that may apply. The current rating of the wiring to the boil
er must exceed 3 amperes and have a cross sectional area of at least 0.75 m
m² in accordance with BS.6500 1984 Table 16. The method of connection to t
he electricity supply MUST facilitate complete isolation of the appliance, prefer
ably by the use of a fused three-
pin plugand unswitched, shuttered socket outlet, both complying with the requi
rements of BS. 1363.
Alternatively, connection may be made via a fused double-
pole isolator having a contact separation of at least 3 mm in all poles and servi
ng the appliance and systemcontrols only.
TECHNICAL DATA
Maximum working head
- 30.5m (100 ft)
Minimum Working Head (Fully Pumped systems)
- 305mm (1 ft)
Minimum Circulating Head (Gravity systems)
- 1.2m(4ft)
Gas supply pressure
- 20 mbar

Maximum Flow Temperature
- 82ºC
Electricity Supply
-
240V ~ 5OHz fused at 3A
Water Connections
Gravity Flow
- R ¾ (¾ in BSP Male)
Gravity Return to injector ‘Tee’
- To accept 28mm copper
Pumped Flow
- R.c. 3¾
(¾ in BSP Female)
Pumped Return using injector ‘Tee’
- To accept 22mm copper
Pumped Return without injector ‘Tee’ Gas supplyConnection
- R. ¾ (¾ in BSP Male)
Gas supply Connection
- R.c. ½
(½ in BSP Female)
Water Content
- 6.5 litres
- 1.43 gal
Appliance weight installed
- 56 kg
- 124 lbs
Appliance weight lift
- 50 kg
- 110 lbs
Page 7
TECHNICAL DATA - Page 8
BOILER
SIZE
INJECTOR
SIZE
GAS RATE
INPUT
OUTPUT
BURNERPRESSURE
m3/h
(ft3/h)
kW
(Btu/h)
kW
(Btu/h)
mbar
in wg
Min
3.1 mm
0.75
(26.57)
8.06
(27500)
5.86
(20000)
3.9
1.6
20/35
1.02
(35.94)
10.9
(37200)
8.06
(27500)
7.5
3.0
Max
1.26
(44.44)
13.48
(46000)
10.26
(35000)
11.0
4.4
Min
3.5mm
1.31
(46.37)
14.07
(48000)
10.26
(35000)
7.5
3.0
35/50
1.56
(55.00)
16.70
(57000)
12.46
(42500)
10.2
4.1
Max
1.79
(63.29)
19.20
(65500)
14.65
(50000)
13.5
5.4

CIRCULATION PUMP SELECTION
The resistance through the heat exchanger when operating with a water flow r
ate producing an 11º C temperature rise at maximum boiler output is shown in
TABLE 2. If othercontrols, such as three position valves are used in the syste
m, the resistance through them, quoted in their manufacturer’s literature must
be taken into account. The pumpmay be fitted on either the flow or return and
MUST be wired directly to the boiler terminal block when fitted to a fully pump
ed system. It must be fitted with two isolating valveswhich are positioned as cl
ose to the pump as possible. Isolation of the valves must always leave the op
en vent unobstructed.
TABLE 2
WATER FLOW RATE
BOILER RESISTANCE
With Injector Tee
Without Injector Tee
litres/sec
gal/min
kN/m²
in.wg
kN/m²
in.wg
20/35
.22
2.92
2.25
9.0
.30
1.2
35/50
.32
4.17
4.73
18.9
.55
2.2
FIG. 3. PRESSURE LOSS ACROSS BOILER
Page 8

TECHNICAL DATA - Page 9
THE SYSTEM
The boiler must be used on Indirect hot water systems only. It is suitable for u
se on sealed or open vented gravity domestic hot water/pumped central heati
ng systems or fullypumped systems.
The system should be designed so that the maximum static head does not ex
ceed 30.5m (100 ft) and a minimum on fully pumped systems of 305mm (1 ft.)
. See FIG. 4.
If a minimum 305 mm (1 ft) head is used extra care should be taken when des
igning the system to ensure that pumping over or sucking down at the vent pip
e cannot occur.
Gravity domestic hot water circuits should have a minimum circulating head of
1.2 m (4 ft). SEE FIG. 6. To prevent reverse circulation in the gravity circuit w
hen the pump isrunning, an injector tee is provided. This must be installed as
shown in FIG 10a.
To prevent nuisance operation of the overheat thermostat, it is important that
where electrically operated zone valves are used the boiler is wired so that it d
oes not cyclewhen the zone valves are closed. Also systems fitted with control
s that close both hot water and central heating circuits while the boiler is still h
ot must be fitted with a by-
passcircuit to dissipate the residual heat within the boiler.
Further information on by-
pass arrangements is provided in later notes and illustrations.
Drain-
off taps should be fitted in the pipework close to the boiler if it is in a low point
of the system.
Note:
Although the system can be emptied using the drain-
off taps installed in the pipework around the system, to empty the boiler it is n
ecessary to remove the drain-
off plug in thefront lower left of the casting. SEE FIG. 2.
Combined Gravity Hot Water and Pumped Central Heating systems.
Where a cylinder thermostat and zone valve are fitted to control the temperatu
re of the domestic hot water it is recommended that a by-
pass be installed in the gravity circuit.A suggested method of doing this is sho

wn in FIG. 6 where the bathroom radiator is connected into the gravity circuit a
nd is fitted with two lockshield valves.
Fully Pumped Systems
The pump must always be wired directly to the boiler terminal block as shown
in FIG. 12.
If a three port diverter valve is used as shown in FIG. 4. a by-
pass is not necessary since one circuit is always open.
Where a pair of two port valves are used, a by-
pass is necessary. The total length of the by-
pass circuit taken from the boiler connections should be greater than 4 metres
of22 mm pipe. It should be fitted with a lockshield valve and adjusted to maint
ain a minimum flow through the boiler of 4.5 litres/mm (1 gal/min). Alternativel
y, the by-
pass canbe provided using the bathroom radiator as shown in FIGS. 4& 5.
Systems fitted with controls which allow the boiler to operate when both the ho
t water circuit and the central heating circuits are closed i.e. mechanically oper
atedthermostatic control valves, must be fitted with a bypass circuit capable of
:-
1 Dissipating a minimum of 1 kW (3400 Btu/h).
2. Maintaining a water flow through the boiler of 9 litres/mm (2 gal/min).
A suggested method of meeting these requirements by using the bathroom ra
diator fitted with two lockshield valves is shown in FIGS. 4& 5.
SEALED SYSTEMS
Installation
The installation must comply with the requirements of BS. 6798 1987 and BS.
5449 Part 1. The B.G. Publication "British Gas Specification for Domestic Wet
CentralHeating Systems" should also be consulted.
Safety Valve
A non adjustable spring-loaded safety valve pre-
set to operate at 3 bar (45 lbf/in²) shall be used. It must comply with BS. 6759
Part 1 and include a manual testing device. Itshall be positioned in the flow pip
e either horizontally or vertically upwards and close to the boiler. No shut-
off valves are to be placed between the boiler and the safety valve.The valve
should be installed into a discharge pipe which permits the safe discharge of s
team and hot water such that no hazard to persons or damage to electricalco
mponents is caused.

Pressure Gauge
A pressure gauge incorporating a fill pressure indicator, covering the range 0-
4 bar (60 lbf/in²) shall be fitted to the system. It should be connected to the sys
tem, preferably atthe same point as the expansion vessel. Its location should
be visible from the filling point.
Expansion Vessel
A diaphragm type vessel to BS. 4814 Part 1 shall be fitted close to the inlet sid
e of the pump. The connecting pipework should not be less than 15 mm (½ in
nominal).Pipework connecting the expansion vessel should not incorporate va
lves of any sort. Methods of supporting the vessel are supplied by the manufa
cturer. The nitrogen or aircharge pressure of the expansion vessel shall not be
less than the hydrostatic head,
(height of the top point of the system above the expansion vessel). To size the
expansionvessel it is first necessary to calculate the volume of water in the sy
stem in litres. The following volumes may be used as a conservative guide to
calculating the systemvolume.
Boiler Heat Exchanger
6.5 litres
Small Bore Pipework
1 litre per kW of system output
Micro Bore Pipework
7 litres output
Steel Panel Radiators
8 litres per kW of systemoutput
Low Water CapacityRadiators
2 litres per kW of systemoutput
Hot Water Cylinder
2 litres
If the system is extended the expansion vessel volume may have to be increa
sed unless previous provision has been made for the extension. Where a vess
el of thecalculated size is not available, the next available larger size should b
e used.
Page 9
TECHNICAL DATA - Page 10
The boiler flow temperature is controlled at approximately 82˚C. The ve
ssel size can now be determined from the following table where V = system v
olume in litres.
Vessel Charge Pressure (bar)
0.5
1.0

Initial System Pressure (bar)
1.0
1.0
Expansion Vessel Volume
(litres)
V X 0.11
V X 0.087
Cylinder
The hot water cylinder must be an indirect coil type or a direct cylinder fitted wi
th an immersion calorifier suitable for operating at a gauge pressure of 0.3 bar
(5 lbf/in²) inexcess of safety valve setting. Single feed indirect cylinders are n
ot suitable for sealed systems.
Method of Make-Up
Provision shall be made for replacing water loss from the system either:
i) from a make-
up vessel or tank mounted in a position higher than the top point of the system
, and connected through a non-
return valve either to the system on the returnside of hot water cylinder or the
return side of all heat emitters.
or
ii) where access to a make-
up vessel would be difficult, by using the mains top up method or a remote aut
omatic pressurisation and make up unit as illustrated in FIG. 5METHODS 1 an
d 2.
Mains Connection
There shall be no connection to the mains water supply or to the water storag
e tank which supplies domestic water even through a non-
return valve, without the approval ofthe local Water Authority.
Filling Point
The system shall be fitted with a filling point at low level which incorporates a
stop valve to BS. 1010 and a double check valve (approved by the National W
ater Council) tobe fitted in this order from the system mains. Refer to FIG. 5 M
ETHOD 1.

FIG. 4 OPEN VENTED FULLY PUMPED SYSTEM FITTED WITH A COMBIN
ED FEED AND VENT
Page 10
TECHNICAL DATA - Page 11

FIG. 5. FULLY PUMPED SEALED SYSTEM
FIG. 6 OPEN VENTED GRAVITY DOMESTIC HOT WATER AND PUMPED
CENTRAL HEATING SYSTEM

Page 11
INSTALLATION INSTRUCTIONS - Page 12
The boiler and its associated equipment will arrive on site in two cardboard ca
rtons. The contents of each carton is as follows:
CARTON 1
CARTON 2
Boiler
Literature Pack containing:
Case Support Plate
Installation and Servicing Instructions
Boiler Mounting Bracket
User’s Instructions
Polythene Bag containing:
Control Systems Pipework and WiringGuide
Injector Tee
Template
Adjustment Screws -2 off
Accessory Packs
Gas Service Cock
Boiler Casing
FIG. 7. TEMPLATE
Place template in proposed boiler position taking due account of the informati
on given previously and the position of the chimney,

(the minimum side clearances areautomatically allowed for). Refer to page 6 f
or top and bottom clearances which can be measured from the template.
Ensure that the template is level and mark hole positions ‘A’.
‘B’, and centre of boiler reference line through the slot in the bottom edge of th
e template.
If the flue is to rise through the ceiling, mark out centre line of hole for flue by
extending the dotted line on template vertically and measure out 160mm from
rear wall asillustrated.
FIG. 8 BOILER MOUNTING PLATE
Remove template and drill holes ‘A’ using a 7mm drill.
Drill holes ‘B’ using a 5mm drill and insert the wall plugs from accessory pack
B into the holes.
Cut hole through wall or ceiling as necessary for intended run of flue pipe.
Using wall plugs, screws and washers (accessory pack A) attach boiler mounti
ng plate to wall ensuring it is level.
Remove the adjustment screws from the polythene bag in the boiler carton an
d screw them into the boiler legs as illustrated in FIG. 9.
Page 12