Chaffoteaux & Maury Sterling FF User guide

STERLING FF
Room Sealed Fanned Balanced Flue
Combination Boiler
GAS SAFETY ~INSTALLATION AND USE) REGULATIONS.
It is the law that all gas appliances are installed by a competant person
in accordance with the above regulations
(For use on natural gas only. G20)
G.C. No 47 980 04
from serial number ............
Installation and
Senrkhg Instructions
(leave these instructions with the user)
Looking Good.Heatfng Better

HealthandSafetyInformation 1
PageNo.
1. INTRODUCTION
1.
1.1.
1.2.
1.3.
1.4.
1.4.1.
1.4.2.
1.4.3.
1.4.4.
1.5.
1.6.
1.6.1.
1.6.2.
1.6.3.
1.6.4.
1.6.5.
1.6.6.
1.6.7.
GeneralDescription,SpecialFeatures,Guarantee
DimensionsFig. 1
TechnicalData
Ckarances
Wall Thickness
RearFlueOutletFig. 2
SideFlueOutletFig. 3,Fig. 3a,Fig. 3b
OtherFlueArrangements,HorizontalFig. 3c
VerticalFlueArrangements,Fig. 3d,Fig. 3e,Fig. 3f Fig. 3g
Descriptionof ComponentsandLocationFig.4
Descriptionof Operation
CentralHeatingFig. 5
HotWaterFig. 6
Gas(alsosee2.7)
FunctionalFlow DiagramFig. 7
SafetyControls
FunctionalFlow Wiring DiagramFig.8
IllustratedWiring DiagramFig.9
2. INSTALLATION REQUIREMENTS
2. 1. General
2.2. Location
2.3. WaterCirculationSystem
2.4. SitingtheFlueTerminalFig. 10
2.5. Air Supply
2.6. ElectricalSupply
2.7. GasSupply
3. SYSTEM GUIDANCE
3.1. General
3.2 SystemControls
3.3. PumpFig. 11
3.4. ExpansionVessel
3.5. MainsWaterConnection
3.6. Filling andRecharging
Fig. 12,Fig. 13(page
12)
3.7. MakeupSystem
3.8. Pipework
3.9. DomesticExpansionVessel
3.9.1. Boiler Replacement
3.9.2. Existing Systems
3.10 Cylinder
3.11 InhibitorsandWaterConditioners
3.12 Add onDevices
3.13 HeatingandHot WaterSystemsFig. 14,Fig. 15, Fig. 16,
Fig. 17
3.14 ShowerApplicationFig. 17a
2
2
3
3
3
4
4
4
5
6
7
7
7
8
8
8
9
10
11
11
11
11
12
12
12
12
13
13
13
13
13
13
13
13
14
14
14
14
14
15
16
(4

CONTENTS (cant)
No.Page
4. INSTALLING THE BOILER
4.1.
4.2.
4.3.
4.4
4.5.
4.6.
47
4.8.
4.9.
4.10.
4.11.
4.12
4.13.
4.14.
GeneralInformation
PositioningtheBoilerFig. 18
RearOutletFlueFig. 19
SideOutletFlueFig.20
Jig PlateFig. 21
GasandWaterConnectionsFig. 22
WaterConnections
GasConnection
Fitting theBoiler Fig. 23
Fitting theSafetyValveFig. 24
Fitting theFlue(upto700mmlong)Fig. 25
Fitting theFlue(over700mmlong)
ConnectionthePressureSwitchFig. 26
ElectricalConnectionsFig. 27
Vertical FlueFigs.28.28a,& Fig. 29
5. EXTERNAL CONTROLS
5.1. ProgrammingandZoneValves
Fig.30 22
5.2. Honeywell& SatchwellControlledZonesFig. 31 22
5.3. FrostthermostatFig. 32 22
5.4. RoomThermostatFig.32a 22
6. COMMISSIONING
6.1.
6.2.
6.3.
6.4.
6.5.
6.6.
6.7.
6.8.
6.9.
6.10.
6.11.
Hot WaterCircuits.Filling Fig.33
CentralHeatingCircuits,Filling, Fig.34G
Lighting theBoilerFig. 35
GasRateAdjustmentFig. 36,37 & Fig. 38
DomesticHotWater,Flow RateAdjustment(seealso6.7,Fig. 393)
AdjustingtheHeatingSystemBy-PassFig. 39
DomesticHot Water.flow RateAdjustmentFig. 39a
PumpSwitchingAdjustmentFig. 39b
CentralHeatingTemperatureDifferential SettingAdjustment Fig. 39c
Fitting theCasingFig.40
TimeClock OperatingInstructions
7. ROUTINE SERVICING
7.1.
7.2
7.3
7.4.
7.5.
7.6.
7.7.
GeneralRequirements 29
To RemoveFrontCasingFig.41 29
To RemoveCombustionChamberFig.42 30
To RemoveBurnerAssemblyFig.43 30
To RemovePilot Fig.44 30
To CleanHeatingReturnFilter Fig.45 30
CleaningandReplacementof Parts 30
To CheckOperationof SafetyValveFig.46 30
17
17
17
18
18
18
18
18
19
19
19
20
20
20
21
23
23
23
24
25
25
25
25
26
26
27& 28
(ii)

iZQNWXG (con0
PageNo,
8. REPLACEMENT OF PARTS
8.1. ToReplaceElectrodesFig.46
8.2. ToReplaceProbeFig. 46a
8.3. ToReplaceSafetyOverheatThermostat105°CFig.47
8.4. ToReplaceOverheatThermostat110°CFig.48
8.5. ToReplaceChangeOverValveMicroswitchFig.49
8.6. ToReplacetheFlow SwitchAssemblyFig. 50
8.7. ToReplaceVenturiFig.51
8.8. ToReplacePrimaryHeatExchangerFig.52
8.9. ToRemoveElectricalControlBoxFig. 53,Fig. 54
8.10. ToReplacePumpHeadFig.55
8.11. ToReplaceChangeOverValveFig. 56& Fig.57
8.12. ToReplaceSecondaryHeatExchangerFig. 58
8.13. ToReplaceAir SeparatorFig.59
8.14. ToReplaceThermistorFig. 60
8.15. ToReplaceBoilerLimit ThermostatFig.61
8.16. ToReplaceD.H.W. ThermostatFig.62
8.17. ToReplaceHigh TensionTransformerFig.63
8.18. ToreplacePrintedCircuit Board Fig. 64,ElectricalboxlayoutFig. 65
8.19. ToReplaceSolenoidsValvesFig.66
8.20. ToReplaceHeatingBodyLiningsFig.67
8.21. ToReplaceFanAssemblyFig.68
8.22. ToReplacePressureSwitch(HorizontalFlue)Fig. 69
8.23. ToReplacePressureSwitch(VerticalFlue)Fig. 69a
8.24. ToRe-pressuriseExpansionVesselFig. 70 .
8.25. To ReplacePressureGaugeFig.71
8.26. ToReplacetheDomesticExpansionVesselFig. 72
8.27. ToReplaceMain BurnerFig. 73
8.28. ToReplaceBurnerManifoldAssemblyFig.74
8.29. ToReplaceExpansionVesselFig.75
8.30. ToReplaceViewing WindowFig.76
8.31. ToReplaceMainGasValveBodyFig.77
8.32. ToReplacetheThermometerFig. 78
8.33. ToReplacetheTimeClockFig. 79
8.34. ToReplaceSafetyValveFig. 80
9. FAULT FINDING
9.1. Logic Sequence
9.2. CentralHeatingOperation
9.3. DomesticHot WaterOperation
9.4. FaultFindingTabularChart
SHORT SPARE PARTS LIST
31
31
31
31
32
32
32
33
33
34
34
34
35
35
36
36
38
37
38
38
38
39
39
39
39
40
40
40
41
41
42
42
42
43
44
45
46
47
Rearcover
(iii)

CONTROL OF SUBSTANC-RMFUJ, TO w
To comply with the Control of Substances Harmful to Health Regulation 1988 we are required to
provide information on the following substancethat is contained in this appliance.
Descriution Combustion Chamber Lining
platerial Alumino Silicone Fibre
Precautionq During servicing, keep the dust generation to a minimum and avoid
inhaling any dust and contact with the skin and eyes. Normal handling
and use will not present any discomfort, although some people with a
history of skin complaints may be susceptible to irritation.
When disposing of the lining ensure that it is securely wrapped and
wash hands after contact.

The STERLING FF is a wall mounted, low water content
fanned balanced flue appliance suitable for central heating
and hot water via a non storage water to water heat
Special features include :
-Output to central heating fully range rated between
l/3 and full output.
exchanger. The maximum output is 23 kW (78480 Btuih).
The boiler is designed for sealed systems only and included
in the appliance are the expansion vessel, circulating pump,
temperature and pressure gauges, safety valve, electric
connection box, domestic expansion vessel and time clock.
-High efficiency.
-Special jig plate enabling all pipework to be
installed before installiig appliance.
-Independent control over central heating flow
temperature and hot water.
1) The standard flue assembly supplied with the boiler is
100 mm (4 in) dia pipe, can be directed to the rear or to
the lef or right and can be extented to a maximum length
of 3 m, or 1.6 metres horizontally using the available 90”
bend (see sections 1.4.1, 1.4.2 and 1.4.3 figures 2. 3, 3a,
3b, 3~).
2) Vertical flue option (see section 1.4.4.).
Guarantee
-Fully adjustable central heating flow temperature.
-regulation between 40” C and 82” C.
-High limit thermostat for both boiler and hot water.
-Water flow switch to protect appliance.
-Suitable for showers with compatible mixer valves.
- 7 day programme time clock.
The manufacturer’s guarantee on this appliance is for 12 months from the date of purchase. The guarantee is void, if the.
appliance is not installed in accordance with the recommendations made herein. ~\_
1.1 DIMENSIONS
B I
c’--
2%
I\
t-1
---
-----
_--
-1-2
w r-
‘KI
I ;
I ’
1 I
+
LI
X-3
1 L
.,- -. , --+
-I
Fig.1
REAR OUTLEl
/ -f
_-
~
SIDE OUTLET
1
A
820.5 32.3
B
391.0 15.4
C
365.0 14.4
D
100.0 4
E
169.5 61‘1
F
654.5 25.7
G
43.0 1.7
H 50.0 2.0
J
75.0 3.0
K
260.0 10.2
L
150.0 6.0
M
972.5 38.3
N
13.0 0.5
P
61.0 2.4
R 30.0 1.2
S
152.0 6.0
T
112.0 4.4
mm
-7 in
2

1.2 Technical Data
Hot water
Input ..._....................................... 28.90 kW 98612 Btulh
Output . .......................... . ....... 23.00 kW 78480 Btulh
Water flow raised
45 “C (81 "F) .............................. 7.4 I/min
Water iIow raised
35 ‘C (63 “F) .............................. 9.5 Vmin
Water flow raised
30 “C (54 “F). ............................. 11.1 Ymin
Maximum temperature.. ............. 60 T
Maximum pressure.. ................... 10 bar
Minimum working pressure.. ...... .6 bar
Gas rate ...................................... 2.743 m3/h
Burner pressure .......................... 11.8 mbar
1.7 ga.I/min
2.1 gaI/min
2.5 gaI/min
140 OF
150 psi
9 psi
96.87 fi3h
4.7 in wg
Central heating
Maximum input.. ........................ 27.64kW 94313 Btti
Maximum output.. ...................... 22.00 kW 75068 Btti
Gas rate (maximum) ................... 2.63 m3/h 92.98 @lh
.lrner pressure.. ........................ 11.2 mbar 4.5 in wg
.,rinimum input ........................... 10.85 kW 37020 Btuih
Minimum output.. ....................... 7.64 kW 26062 Btu/h
Gas rate (minimum) ................... 1.0 m3/h 35.31 ft3/h
Burner pressure.. ........................ 1.5 mbar 0.6 in wg
Minimum flow rate ..................... 300 lib 1.1 gal/min
Maximum pressure.. ................... 2.5 bar 36.5 psi
At the maximum pressrrre loss of the fiue
Temperature of the products of
combustion : ... .............. . ....... 98 T 208 OF
The CO content of the dry free air
products of combustion : .. ...... 0.0136%
Natural gas Pressure switch - DUNGS 88 Pa I 49 Pa
Connections
Gas.............................................................. 22 mm copper
Heating flow ................................................ 22 mm copper
Heating return.. ............................................ 22 mm copper
Mains cold water inlet.. ................................ 15 mm copper
Hot water outlet.. ......................................... 15 mm copper
Electrical supply 240 V - 50 Hz, fused at 3A.
Electrical consumption ..................._............. 195 watts
Internally fused, two at 2A (BS 4265)
Weight .... ...... ._.._.._........_.......................... 42 kg 92.4 lb
Water capacity ............ ._.,......................... 4 Iitres 7 pints
Ignition - ANSTOSS continuous spark generator
Ignition electrode - SAPCO
Ignition probe - SAPCO
Thermistor - SIEMENS
Boiler fiiit thermostat - SOPAC /JAEGER (85X)
Hot water limit thermostat - SOPAC /JAEGER (57°C + 3°C)
Safety overheat thermostat (TOKOSWHCH - (105°C)
(manual reset) (ELMWOOD
Overheat high- Iiit thermostat (TOKOSWITCH - (1lO’C)
(automatic reset) (ELMWOOD - (105’C)
Gas valve - AEMF
Fan motor - SEL
Manifold injectors 14 of ..... . .. . 1.28 mm 0.05 in
Gas section restrictors 213 valves 4.4 mm 0.17 in I Pump head - GRUNDFOS UP 15/60
l/3 valve.. .... 2.3 mm 0.09 in C.H. expansion vessel initial charge pressure - 0.65 bar (9.6 psi)
security valve ...... no restricior fitted Domestic expansion vesseI initii charge pressure . 2 bar (30 psi)
3 Minimum clearances around Boiler
Top above air duct ......... 50 mm (2 in)
Bottom below case. ......... 150mm (6in)
Sides ..... . .... . . . . ........ 100mm (4in)
Front. .. . .. .... ................ 6OOmm(24in)
1.4 Wall Thicknesses
The standard fIue assembly can accomodate the folrowing thicknesses.
Rear : from 55 mm to 576 mm
Side : from 55 mm to 392 mm
(this allows for a minimum dearance of 100 mm between the appliance and the side wall. As this dimension
increases, so the maximum side waII thickness available decreases).
Extension flue assemblies are available to accomodate waII thicknesses of:
Rear : from 577 mm to 2876 mm
Side : from 393 mm to 2692 mm
See figs. 2 and 3 for details of number of extensions required.
IMPORTANT NOTE : The extension ducts supplied. up to a maximum of 3, wiII in fact permit a greater length than
indicated to be covered. The ducts MUST be cut so that the maximum length from the centre Iine of the flue turret to
the outermost point of the air duct DOES NOT EXCEED 3 metres horizontal. Greater length must not be used.
See sections 1.4.1. 1.4.2. 1.4.3.
3
1.2
1.3

1.4.2
Rear Flue Outlet Hobontal
To cut flue assembly to length
- Measure wall thickness (T).
- Add 74 mm, tthis will give required lentgh Q.
- Mark plastic air duct for length (L) and cut off
surplus (from plain end).
N.B. If extension sections are used ensure these are
fiily pushed together, see figs. 3b and 3c and a fall of 5
mm per metre length should be provided (see section
- Cut off same amount from aluminium flue duct
Flueextensionaccessory
Part No.62823.00
(G.C.264459)
(1 metre length)
REAROUTLETASSEMBLY
‘ig. 2 I
Side Flue Outlet Horizontal
internal
To cut ffue assembly to length
- Measure from external wall face to centre line of
STERLING FF and substract 37 mm (this will give
required length “L”).
- Cut off surplus i?om plastic air duct (plain end).
N.B. If extension sections are used ensure these are
filly pushed together, see figs. 3b and 3c and a fall of 5
- Cut off same amount from
Fig. 3
SIDEOUTLET ASSEMBLY
Fig. 3a
PLASTIC AIR DUCT
Other Flue Arrangements Hotizontal
1. Distance from internal comer 300 mm without
kit,107 mm with kit No 76216 (GC No 264 833).
2. Distance below balconies or eaves 200 mm
without kit, 107 mm with kit No 76216 (GC No
264833).
3. Appliance is normally supplied packed with
standard 650 mm staight flue section. Additional
straight extension lengths of 1 metre, part No
62823 (GC No 264 459), can be use up to a total
straight length of 3 metres. It is also possible to
incorporate one bend in the flue using part No
65572 (GC No 264 835). In this case the length
Ll + 12 should not exceed 1.6 metres
Fig. 3c horizontally.
4
should not exceed 1.6 metres

1.4.4 Vertical Flue Arrangements
Fig. 3 d
a) Straight ffue (fig. 3 d)
1) Adaptor.
2) Extensions (9.5 m maximum).
3) Roof flashing.
4) Terminal.
6) Reducer.
Fig. 3 e
--I
Fig. 3 g
b) Flue with two 45O bends (fig. 3 e)
1) Boiler adaptor.
2) Extensions (8 m maximum).
3) Roof flashing.
4) Terminal.
5) 45’ bend.
6) Reducer.
c) Flue with four 45’ bends (fig. 3 f and 3 g)
1) Adaptor.
2) Extensions (6 m maximum) tig. 3 f and 3 g
including horizontal (2 m maximum) fig. 3 f.
3) Roof tlashiig.
4) Terminal.
5) 45’ bends (x 4 maximum) fig. 3 f and 3 g.
6) Reducer.
With the exception of (3) roof fIashing and (4)
terminal, all other fittings are designed for interd
installation only.
N.B. In these two arrangements tigs. 3 f and 3 g, the
total length of straight extensions m not exceed 6
meters with a maximum of 4 x 45” bends.
Horizontal run & not exceed 2 meters.
5

1.5 Description of Components and Location
1
2
6
3
35
27
-
10
-
2i 22 20 31 19 23 17 18’25
Fig. 4
The appliance is mounted in a steel case which has a
white epoxy resin paint finish.
1. Chassis:
The chassis is a rigid plated mild steel pressing on which
all components are mounted.
2. Flue hood:
Is an aluminium alloy casting onto which the fan is
mounted.
3. Combustion chamber:
This is assembled from a number of components
mounted onto the chassis. The front panel is simply
removed for servicing complete with the expansion vessel,
a hook is fitted below the appliance to accept and retain
the panel during servicing.
4. Expansion vessel:
The expansion vessel has a capacity of 5.4 litres (1.19 gal)
and is sized for a normal system water content where the
load is equivalent to the maximum output of the boiler.
The charge pressure is 0.65 bar.
5. Flame supenrision device (not illustrated).
6. Multigas burner comprising: stainless steel blades (14)
and a manifold with injectors (14).
7. Gas section including two stage solendid valves and
security solendid valve.
6. Secondary heat exchanger :
The secondary heat exchanger is a plate type heat
exchanger. A thermostat is fitted on the pipework limiting
the domestic hot water temperature to a maximum of 57
f3” c.
9. Change over vaIve :
The valve is activated by a demand for domestic hot
water, closes the heating circuits, and directs water to the
secondary heat exchanger.
fO.EIectriciaI box containing :
Mains connection
Fuses
Printed circuit boards
Connections for external controls
Connections for fan, pressure switch and flow switch
Connections for pump
Connections for change over valve and for gas solenoid
valve
Indicator LEES.
.ll. Solenoid valve :
Block on which 4 valves are mounted :
l/3 valve -1st stage valve-heating and hot water (blue)
2/3 valve - full output to hot water (black)
2/3 valve - (variable valve) central heating (orange)
Security valve (grey).
12. Grundfos pump motor
13. Air separator and vent directly connected to the pump
inlet (not illustrated).
14. Regtdation screw to adjust output to heating (2/3
valve).
15. Heating body compristig :
Copper finned tube heat exchanger protected with silicone
resin paint. Combustion chamber in aluminium coated
steel. Combustion chamber lining - ceramic fibre panels.
16. High limit thermostat (manual reset).
17. Water service tap (not illustrated).
18. Flow isolating valve - heating (not illustrated).
19. Gas service tap (not illustrated).
20. Domestic hot water outlet with regulator (not
illustrated).
21. Safety valve with drain tap (not illustrated).
22. Heating return isoIating vaIve with filter (not
illustrated).
23. Indicator LEDS.
24. Thermometer indicating boiler flow temperature.
25. Manual lock out reset.
26. Selector switch - hot water or&/OFF/heating and hot
water.
27. Adjustment to regulate heating tlow temperature.
26. Pressure gauge.
29. Pressure switch (not illustrated).
30. Domestic expansion vessel (not illustrated).
31. Water flow switch (not illustrated).
32. Tiie clock.
33. Fuses.
34. Data badge position.
35. Control thermistor.
6

~6 Descdption of Operation
(38) the operation of which interrupts the electrical supply
to the security solendid valve and extinguishes the burner.
The STERLING FF a is combination boiler providing
central heating and hot water. Hot water is provided on
a demand basis. For the duration of the demand for
hot water the central heating is interrupted.
The appliance operates in two modes. A hot water only
setting where it operates only on hot water demand
and a hot water + central heating setting providing
central heating and switching to hot water on demand.
1.6.1 Central Heating (see fig. 5)
The pump (21) circulates water which returns to the
boiler via the return valve (31) which incorporates a
filter (30) Before reaching the pump it passes through
an air separator and air purger (17). The return water
passes through the heat exchanger (2) where it is
heated. It then passes through the change over valve
(19) which in heating mode is in its rest position and
out via the flow valve (27) to the radiator circuits (34).
An expansion vessel (13) is fitted in the primary circuit.
Temperature control is by means of a temperature
sensing thermistor and potentiometer. These signals
are fed to a comparitor.
When the flow approaches the set temperature, the
variable gas valve is closed and the boiler continues to
fire on l/3 soleno?d valve (11). When the set
temperature is reached, the boiler switches off. If
flow temperature reduces, the l/3 solenoid valve
opens followed by the variable solenoid valve (10).
Temperature adjustment is between a minimum of
40°C approx. and a nominal maximum of 82°C.
The boiler is protected by high limit thermostats (4) and
1.6.2 Hot Water (see fig. 6)
When there is a demand water flows in from the cold
mains supply (26) through the water section part (35) of
the change over valve (19). The inclusion of a venturi (24)
produces high pressure under the diaphragm (23) causing
it to rise. This movement is transmitted to the change over
valve closing the heating port and opening the hot water
port, as shown (20). The primary water heated by the
boiler now passes through the water to water heat
exchanger (18) where it flows through alternate plates
indirectly heating the DHW.
The rising of the change over valve spindle causes :
1. The opening of a microswitch stopping the pump.
This circuit is remade by a second microswitch making
when the hot water port is fully open.
2. The by-passing of the boiler thermistor brings the
boiler under control of a fixed temperature thermostat
(32) which operates on the 23 fmed solenoid (12).
The D.H.W. flow rate is adjustable by a restrictor (25) and
a liiiting thermostat (32) reduces the gas rate when the
domestic hot water reaches 57’C by interrupting the
electrical supply to the hot water solenoid (12).
If the primary circuit reaches 85°C the limit thermostat (16)
closes both solendids valves.
A domestic expansion vessel is fitted in the D.H.W. circuit
(36).
Central Heating
16
3, ----lO.ll-
I ILL
/I----.-.
17 11 -111
IL 'I IL- I"
T
16
L*-l ‘---q ,*
30
27
31
Fig. 5 Fig. 6
Hot water
27
1
16
7
1.6

1.6.4
1.6.5
r:
Gas (see figs. 5 and 6)
When the main gas tap (33) is turned to the on position
gas is admitted to the gas section (7).
When there is a demand for heating or hot water, the
security solenoid valve (9) and the l/3 soleno’id valve
open together, which allows gas to pass to the burner.
Srrnultaneously the hight tension transformer is energised
and produces a stream of sparks from the ignition
electrodes (3) whitch light the main burner.
The flame supervision (5) is controled by ionisation
circuit.
If the main burner is not established after 5 seconds, the
boiler falls safe to lock out and has to be reset manualy.
There are 4 solenoid valves : the right hand (grey) valve
(9) is the security valve, the blue valve (11) fixed at l/3 of
max rated output, the hot water (black) valve (12) fixed at
2/3 of maximum rated output, the left hand central
heating (orange) valve (10) which is variable up top 2/3
maximum rated output.
The gas admitted by the orange valve is varied by adjuster
(6) (see section 6.4).
FUNCTIONAL FLOWDIAGRAM
Summer
D.H.W.
High
Limit Water 113gas
-+ Stat + Pump --+ Flow
Switch 2 Security -
I i-l
(manual reset)
L
F -ig. 7
1.6.6 Safety Controls
Should the central heating water flow reduce to below 3OC’
In addition to the normal safety controls the STERLING FF Uh (1,l gal/min) the gas supply to the burner is turned 01
incorporates the following feature. via the flow switch (No.31 - page 6). see figs 5 & 6 (37).
OFF Fan ON
no I
I
5” lockout time
85°C Limit
Thermostat Thermistor
105 / 110°C High Limit
Thermostats
2l3 Orange
Solenoid I+
8

1.6.7 FUNCTIONAL FLOW WIRING DIAGRAM
PRESSURE BOILER WATER FLOW POTENTIOMETER
HEATING
bk 9e Y
L 3A L 2A 2A N N
- h-
L-l Y-
LINK or EXTERNAL -w w ^C^. .-.-I
rzl SkG”HlII
r
SOLENOID
VALVE 1
PRINTED CIRCUIT BOARD
-......-,. _I.”
INTER SWITCH bk
STAT -
HIGH LIMIT
SECURITY (2)
,-CHANGE OVER VALVE,. .
MICROSWITCHES :
Fig. 8
k
RESET
SWITCH
IGH RATE
I
IGNITION ELECTRODES
P
FLAME
w SUPERVISION
BOILER
THERMISTOR
HEATING
b = blue
bk = black
br = brown
ge = green
gr = grey
or = orange
r = red
v = violet
w = white
y = yellow
9
1.6.7

1.6.8 ILLUSTRATED WIRING DIAGRAM
FAN
HIGHLIMIT
THERMOSTAT110”
BOILERTHERMISTORHEATING
WATERFLOWSWITCH
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BOILERPOTENTIOMETER
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10

2 INSTALLATION REQUIREMENTS
2.1 General
2.2
The installation of the boiler must be in accordance
with Gas Safety (Installation and Use) Regulations,
Building Regulations and current Byelaws of the Local
Water Undertaking. It should be in accordance also
with the current BS Codes of Practice and the British
Gas Specifications for Domestic Wet Central Heating
Systems and any relevant requirements of the local
Gas Region and Local Authority Building Standards
(Scotland) Regulations and the Safety document 635
the Electricity at Work Regulation.
Detailed recommendations are stated in the following
British Standard Codes of Practice:
B.S. 6891, B.S. 6798, B.S. 5440 : 1and 2, B.S. 5449: I,
B.S. 7593, BS 5546B.G.DM2, B.S. 4814. B.S. 7074 1
e 2, B.S. 7671.
Note : Gas Safety Installation and Use Reg. It is the
law that all gas appliances are installed by competant
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 compliance wlth the law.
Location
The boiler is not suitable for external installation. The
position chosen for the boiler must permit the
provision of a satisfactory flue termination. The
location must also permit adequate space for servicing
and air circulation around the boiler. The surface on
which the boiler is mounted must be of non
combustible material.
The boiler may be installed in any room or internal
space although particular attention is drawn to the
requirements of the current B.S. 7671 and, in
Scotland, the electrical provisions of the Building
Regulations applicable to Scotland, with respect to the
installation of a heater utilising mains electricity in a
room or internal space containing a bath or shower.
Where the installation of the boiler will be in an
unusual location special procedures may be necessary
and BS 5546 gives detailed guidance on this aspect.
A compartment used to enclose the boiler must be
designed and constructed specifically for this purpose.
An existing cupboard or compartment may be used
provided that it is modified for the purpose.
Details of essential features of cupboard/compart-
ment design are given in BS 6798.
2.3 Water Circulation System
2.4
The STERLING FF is suitable for SEALED SYSTEMS
ONLY and should be installed in accordance with the
relevant recommendations given in BS 6798, BS
5449:l (for the smallbore or/and microbore systems)
and the British Gas Specifications for Central Heating
Systems.
Sitfng the Hue Terminal
Refer to section 1.4 for details of wall thicknesses
which can be covered.
Detailed recommendations for flueing are given in BS
5440 Pt 1. The following notes are intended to give
general guidance.
The boiler must be installed so that the ffue terminal is
exposed to external air. The boiler must NOT be
installed so that the terminal discharges into another
room or space e.g. outhouse or closed in lean-to. It is
important that the position of the terminal allows a
free passage of air across at all times. The miniium
acceptable clearances from the terminal to
obstructions and ventilation openings are specified
below (fig. 10).
Horizontal Flue
Terminal positions Mii clearances
A - Directly below an opening, windowsetc
or adjacent to an opening ............... . .... 300 mm
B - Below gutters soil pipes or drain pipes ... 75 mm
C - Below eaves .. ...... .. ............. . ..200 mm*
D - Below balconies or car port roof ............ 200 mm*
E - From a vertical drain pipe or soil pipe .... 75 mm
F - From an internal or external corner _....... 300 mm*
G - Above ground roof or bs.lcony level ....... 300 mm
H - From a surface facing the terminal. . ...... 600 mm
J - From an opening in the car port
(e.g. door or window) into dwelling ........1200 mm
K - Vertically from a terminal on the same
wall ........................................................1500 mm
L - Horizontally from a terminal on the
same wall .. ........... ...... ............. ....... 300 mm
* (107 mm) minimum clearance using
kit No. 76216.CK)(G.C.264833)(seesect.h 14.3,fig.3c)
Vertical Ffae
Terminal positions Min clearances
M - Above intersection with Roof ................ 150 mm
L
Fig. 10
11

BUILDING REGULATIONS excerpt.
Approved document J Part B 1.4 (C) (D).
C) Protect with a terminal guard fitted centralIy over
the terminal if it could come in contact with people
near the building or be subjected to damage.
D) Designed so as to prevent the entry of any matter
which might restrict the ffue.
(A terminal guard G.C. No 381 782 is available from).
Quinnel Barret & Quinnel Wiieworks
Old Kent Road
London SE15 INL Tel. [phone]
The air inlet/outlet duct and the terminal of the
appliance must not be closer than 25 mm (1 in) to
any combustible material . Detailed recommendations
on the protection of combustiable material are given
inBS5440Pt 1.
IMPORTANT NOTICE : TIMBER FRAMED HOUSES
IF THE APPLIANCE IS TO BE FITTED IN A TIMBER
FRAMED BUILDING IT SHOULD BE FITTED IN
ACCORDANCE WITH THE BRITISH GAS
PUBLICATION - “GUIDE FOR GAS INSTALIATIONS IN
TIMBER FRAMED HOUSING” reference DM2. IF IN
DOUBT, ADVICE MUST BE SOUGHT FROM THE
LOCAL REGION OF BRITISH GAS OR C.O.R.G.I.
2.5 Air Supply
The room in which the boiler is installed does not
require a purpose provided air vent.
If the boiler is Installed in a cupboard or compartment
permanent air vents are required in the cupboard or
compartment, one at high level and one at low level
either direct to the outside air or to a room. Both high
and low level air vents must communicate with the
same space.
Position of vents Air fivm room Air direct fivm outside
High level 261 cm2 (40 in2) 130 cm2 (20 in2)
Low level 261 cm2 (40 in2) 130 cm2 (20 In2)
2.6 Elect&al Supply
- This appliance must be earthed.
- All wiring externaI to the appliance must conform to
the current B.S. 767 1.
- The STERLING FF requires a 240 V - 50 Hz supply.
- Connection of the appliance and any system controls
to the mains supply must be through a common
isolator and must be fused at 3A maximum.
This should preferably be an unswitched shuttered
socket outlet and 3 pin plug to BS 1363. AltemativeIy,
a double pole isolating switch may be used, provided
it has a minimum contact separation of 3 mm in both
poles. The isolator should be clearly marked showing
its purpose, preferably positioned close to the
appliance.
-Fuse the supply at 3A.
-The suppIy cord must be 0.75 mm2 (24 x 0.2 mm)
three core to BS 6500 Table 16.
2.7 GasSupply
The STERLING FF requires:
2.743 m3fh (96.87 A3/h) gas Ilow.
The meter and supply pipes should be capable of
delivering this quantity of gas in addition to the
demand from any other appliances in the house.
The complete Installation must be tested for
soundness as described in BS 689 1.
3
SYSTEMGUIDANCE
3.1 General
The low water content STERLING FF boiler indudes
the expansion vessels. safety overheat thermostat,
temperature and pressure gauges, and safety valve.
The flow temperature is adjustable and gives a
nominal 82 ‘C (180’ F) on its maximum setting.
When the appliance is connected to a vertical flue. the
temperature adjustment must not be set below the
midway position.
Detailed recommendations for water circulation are
given In BS 5546. Whilst the boiler provides hot
water, there may be occasions when a cylinder wiU be
used, for instance, if the property has two bathrooms.
Detailed recommendations of this application are
given in sections 3.13. Thermostatic control should be
used in the heating circuits and the cylinder if one is
fitted.
It must be remembered that a combination appliance
has a limited volume of hot water that can be
supplied at any one time for a given temperature.
Indeed in most respects it is equivalent to a multipoint
water heater and many of the contraints associated
with multipoints apply equally to combination boilers.
The appliance has two separate functions, to provide
heating and hot water on demand. It can have a third
which is to supply hot water high demand through the
use of an Indirect cylinder, where there is more than
one bathroom or if the standard and appointments of
the property, such as basins in all bedrooms and a
large kitchen indicate a high usage of hot water.
Hot water produced IndiiectIy through a cylinder can
be used to satisfy high simultaneous demand outlets -
bathrooms etc, whilst the benefits of high effciency in
generally small quantities of hot water, can be fully
utilised in kitchens, cloakrooms and so on.
Separate time and temperature control over hot water
generated in this way can be achieved by the use
either of two port valves or three port valves of a flow
share or priority pattern.
It is also possible, where the occupation of the house
is variable, to provide either for a small or large load.
This is best achieved with a taII, small diameter cylinder.
See section 5 for possible wiring arrangements.
A domestic expansion vessel is fitted to the boiler with
a capacity of 0.16 litres. prior to the secondary heat
exchanger which enables the boiler to be connected
to a cold main water supply containing a non-return
valve or any device containing a non-return valve.
12

IF THE MAINS COLD WATER SUPPLY IS IN
EXCESS OF 10 BAR (150 PSI) A PRESSURE
LIMITER MUST BE FITTED TO AVOID EXCESSIVE
PRESSURE BEING APPLIED TO THE BOILER.
When replacing an existing cylinder storage system
with STERLING FF it is essential that all redundant
pipework is removed and dead legs eliminated,
In properties where there are multiple draw-off Points
on different levels consideration should be given to
the use of non-return valves in the secondary hot
water system to avoid “active dead legs”. No non-
return valve should be less than 1 m (3 It) above the
top of the appliance and ideaIIy should be as close as
possible to the hot water outlet.
At the design flow temperature and the initial system
pressures quoted the maximum allowable system
volume is 75 Iitres.If the water volume is not known
and cannot be accurately assessed from
manufacturers data the following volumes may be
used to give a conservative estimate of the system
volume.
Boiler.. ......... . .. ................,.... ..........4 litres (0,8 gals)
Small bore pipework ............._.__...0.3 litres (0.07 gals)
Microbore pipework. .........................7 litres (1.5 gals)
Steel panel radiators ......................2.3 litres (0.5 gals)
per 0.292 kW (1000 Btu/h) of system output
3.2 System controls
The boiler is electricaky controlled and is suitable for
most control schemes currently available including
thermostatic radiator valves and motorised valves.
Hot water cylinder ... .. . ........._...2 litres (0.44 gals)
If the volume exceeds 75 Iitres an additional vessel
wilI be required fitted In the flow from the appliances.
Refer to BS 7074 Pt. 1 or BS 5449 for details of sizing.
3.5 Mains water connection
When using motorised valves the controls should be
arranged to switch off the boiler when circuits are
satistield. The boiler requires a mink-num flow rate of
300 L/h (1.1 gaI/min) and consequently, if
thermostatic radiator valves are fitted to alI radiators, a
by pass will be necessary. This will ensure that the
boiler will operate correctly when all TRVs are closed.
(see fig. 17).
3.6
3.3 Pump
There shall be no permanent connection to the
Heating System Pipework for filling or replenishing
without the approval of the Local Water Authority (see
Byelaw No.14 and figs. 12 and 13).
Fdlhg point (see Bs 5449)
Filling and recharging can be done :
1) Through a temporary hose connection to mains
water.
The boiler is fitted with a Grundfos UP.15160 pump
head. The graph (fig. 11) indicates the residual head
available for the system.
A stop-valve should be fitted to the service main outlet
and a double check valve assembly and stop-valve
should be fitted to the system side of the temporary
hose (see fig. 12).
flow rate in g.p.m.
6
3.7
2) A cistern used for no other purpose connected to
the mains water. The static head provided by the
cistern m be sufticient to satisfy the designed Initial
system pressure. The supply pipe from the cistern
should include the double check valve assembIy and
stopcock (see tig. 13).
Make up system
3.8
Provision must be made for replacing water lost from
the system indicated by a reduction in pressure
shown on the pressure gauge. Recharge through the
ftiing point (see section 3.6).
Pipework
Fig. 11
flow rate in litres/hour
3.9
Pipework can be of copper or suitable plastic, small
bore or microbore with capillary or compression
jointing to a high standard. Leak sealant must not be
used in the system.
3.4 Expansion vessel Domestic expandon vessel
The expansion vessel which is fitted on the front of
the combustion chamber accomodates system water
expansion. The vessel has a capacity of 5.4 litres
(1.19 gals) and is charged to a pressure of 0.65 bar
(9.7 p.s.i.).
THE CONNECTION IN THE CENTRE OF THE
EXPANSION VESSEL IS A CHARGING AND NOT A
VENT POINT.
The expansion vessel which is fitted on the cold water
supply to the secondary heat exchanger accomodates
domestic hot water expansion. The vessel has a
capacity of 0.16 litres (0.035 gals) and is charged to a
pressure of 2 bars (30 p.s.i.) ; it has a maximum
working pressure of 10 bars with an allowable
pressure peak of 14 bars.
per 0.292 kW
13

Air inlet
valve
Double check Hose
valve assembly pion;y-++ zE
@+P SUPPlY
valve jj
I’ jj
Test cock \~-zd!
Te;irgw
(a) Non-automatic filling and make-up. Temporary hose filling loop avaible, Pt.No.CHL.112
Fig. 12
%o be located
above highest
point in the
system and
satisfy the
designed initial
system pressure
Overflow Mains
Fig. 13
(b) Automatic filling and make-up.
3.9.1 Boiler replacement (retrofit)
In an old system where the boiler is being replaced,
we recommend the use of p strainer, fitted with a
drain tap on the heating return, designed to retain
scale particles and other solid debris It is good practice
to use a chemical cleaner with a floctuating agent,
used as recommended by the cleanser manufacturer,
to clean the system before the old boiler is removed.
(see BS 7593).
3.9.2 Extsting systems
Valves and joints should be carefulIy checked for leaks
and the appropriate action should be taken either as a
repair or replacement. The old open system has
probabfy only been subjected to a pressure of 0.4 bar
or less. When you change to a sealed system where
the charge pressure will be 1.0 bar and the running
pressure exceeding .1.5 bar, consideration should be
given to the replacement of radiator valves with a
pattern capable of sealing at the higher pressures.
3.10 Cylinder
Where a domestic hot water cylinder is used with the
STERLING FF it MUST be of the indirect and high
recovery type to BS 1566 Pt 1 Single feed cyIinders
are not suitable for use with this appliance. Flow and
return pipework to the cylinder should be in 22 mm
pipe.
3.11 Inhibitors and water conditioners
(see BS 7593)
Chaffoteaux et Maury generalIy recommend the use
14
3.12
of inhibitors in systems using the STERL-ING FF boiIer.
The following are the appliance manufacturer’s
recommendations :
1)Use or@ a British Gas or sImiIar approved inhibitor.
These manufacturers can assist with the selection.
Grace Dearbon Ltd - WIdnes - Cheshire WA8 8 UD
Telz051424 5351.
Fernox Manufacturing Company Limited Britannica
Works, Clavering, Essex CBI1 4Qz
Tel: [phone].
2) Use only the quantities specified by the inhibitor
manufacturer.
3) Cleanse the system as required by the inhibitor
manufacturer.
4) Add inhibitor only after flushing when fmally re-
filling the system.
5) In-line water conditioners both of chemical and
magnetic type are suitabIe for use with the S?TIRUNGFF.
Add-on devices
It is important that no external control devices e.g.
economisers be directIy fitted to this appliance unless
covered by these installation instructions or agreed
with the manufacturer in writing. Any direct
connection of a control device not approved by the
manufacturer could make the guarantee void and also
infringe the Gas Safety (InstaIlation & Use) Regulations.