Bosch Worchester GREENSTAR ZWB 7-27 HE combi User guide

Installation and Servicing Instructions
GREENSTAR HE combi
Wall mounted condensing boiler for central heating and mains
fed domestic hot water
6 720 610 577-00.10
ZW 7-27 HE combi GC-Number: 47 311 55
6 720 610 576 GB (02.05) OSW

6 720 610 576 GB (02.05)
2
Contents
Contents
Safety precautions 3
Symbols 3
1 Details of the appliance 4
1.1 EC Declara ion of Conformi y 4
1.2 S andard package 4
1.3 Descrip ion of appliance 4
1.4 Accessories 5
1.5 Casing dimensions 5
1.6 Layou of appliance 6
1.7 Func ion 7
1.8 Elec rical wiring diagram 8
1.9 Technical da a 9
2 Installation regulations 11
3 Installation 11
3.1 Impor an remarks 11
3.2 Domes ic ho wa er 12
3.3 Sealed sys ems 12
3.4 Si ing he appliance 13
3.5 Wall moun ing frame assembly 14
3.6 Pre-piping he sys em 14
3.7 Fi ing he appliance 15
3.8 Checking he connec ions 16
3.9 Flue Sys ems 16
3.9.1 Si ing he Flue Terminal 17
3.9.2 Ins alla ion of he flue 18
3.9.3 Flue duc prepara ion and assembly 20
4 Electrical connections 21
4.1 Connec ing he appliance 21
4.2 Mains Vol age ex ernal con rols connec ions 22
5Commissioning 23
5.1 Commissioning 23
5.2 Swi ching he appliance on/off 24
5.3 Swi ching on he cen ral hea ing 24
5.4 Sys em con rols 24
5.5 Se ing he domes ic ho wa er
empera ure and flow ra e 24
5.5.1 Domes ic ho wa er empera ure 24
5.5.2 Ho wa er flow ra e 25
5.6 Summer mode (ho wa er only) 25
5.7 Fros pro ec ion 25
5.8 Pump an i-seize func ion 25
5.9 Faul Condi ion 25
6 Individual settings 26
6.1 Mechanical se ings 26
6.1.1 Checking he size of he expansion vessel 26
6.1.2 Se ing he cen ral hea ing flow empera ure 26
6.1.3 Changing he hea ing pump charac eris ic 26
6.2 Se ings on he Bosch Hea ronic 27
6.2.1 Opera ing he Bosch Hea ronic 27
6.2.2 Selec ing he pump con rol mode for cen ral
hea ing mode (Service Func ion 2.2) 27
6.2.3 Se ing he an i-cycle ime
(Service Func ion 2.4) 27
6.2.4 Se ing he maxim CH flow empera ure
(Service Func ion 2.5) 28
6.2.5 Se ing he swi ching difference
(Service Func ion 2.6) 28
6.2.6 Se ing he hea ing ou pu
(Service Func ion 5.0) 28
6.2.7 Cons an ho wa er cycle ime
(Service Func ion 6.8) 28
6.3 Se ing he gas/air ra io 28
7 Converting the appliance to different
gas types 29
7.1 Se ing he gas/air ra io 29
7.2 Tes ing combus ion air/flue gas a se
hea ou pu 31
7.2.1 Tes ing he O2 or CO2 level in he
combus ion air 31
7.2.2 Tes ing CO and CO2 31
8 Maintenance 32
8.1 Pre-Service Check Lis 33
8.2 Descrip ion of servicing opera ions 34
8.3 Replacemen of Par s 38
8.3.1 PCB con rol board and ransformer 38
8.3.2 Fan Assembly 39
8.3.3 Pump 39
8.3.4 3-way diver er valve 40
8.3.5 3-way diver er valve mo or 40
8.3.6 Sensors 40
8.3.7 Gas Valve 41
8.3.8 Domes ic Ho Wa er Hea Exchanger 41
8.3.9 Elec rode assembly 41
8.3.10Pressure gauge 41
8.3.11Expansion vessel 41
8.3.12Pressure Relief Valve 41
8.3.13Burner 41
8.3.14Flow swi ch 42
8.3.15Primary Hea Exchanger 42
9Appendix 43
9.1 Faul Codes 43
9.2 Shor par s lis 44
9.3 Hea ing/ho wa er ou pu se ings (N.G.) 45
9.4 Hea ing/ho wa er ou pu se ings (L.P.G) 45
9.5 Opera ional Flow diagrams 46
9.5.1 Domes ic ho wa er func ion 46
9.5.2 Cen ral hea ing func ion 47

6 720 610 576 GB (02.05)
Safety precautions
3
Safety precautions
If you smell gas
BTurn off gas service cock a he me er.
BOpen windows and doors.
BDo no opera e any elec rical swi ches.
BEx inguish any naked flames.
BTelephone your gas company.
If you smell fumes from the appliance
BSwi ch off appliance (see page 24).
BOpen windows and doors.
Fitting and modifications
BFi ing of he appliance or any con rols o he appli-
ance may only be carried ou by a compe en engi-
neer in accordance w h he Gas Safe y (Ins alla ion
and Use) Regula ions 1998.
BFlue sys ems mus no be modified in any ways o her
han as described in he fi ing ins ruc ions.
BThis appliance is for use on sealed primary sys ems
only.
Maintenance
BThe user is recommended: o have he sys em
regularly serviced in order o ensure ha i func ions
reliably and safely.
BUse only original spare par s!
Combustible materials
BDo no s ore or use any combus ible ma erials
(paper, hinners, pain s e c.) in he vicini y of he
appliance.
Health and safety
BThis appliance con ains no asbes os produc s.
BThere is no po en ial hazard due o he appliance
being elec rically unsafe.
BThere are no subs ances used in he cons ruc ion
ha are a po en ial hazard in rela ion o he COSHH
Regula ions (Con rol of Subs ances Hazardous o
Heal h Regula ions 1988).
Combustion air/Ambient atmosphere
BThe combus ion air/ambien a mosphere should be
kep free of chemically aggressive subs ances (e.g.
halogena ed hydrocarbons which con ain chlorine or
fluorine compounds). This will preven corrosion.
Instructions to the customer
BExplain o he cus omer how he appliance works and
how o opera e i .
BAdvise he user ha he/she mus no make any modi-
fica ions o he appliance or carry ou any repairs on i
BThese ins ruc ions are o be lef wi h he user or a
he Gas me er.
BImpor an : These ins ruc ions apply in he UK only.
Symbols
Safety instructions in his documen
are iden ified by a warning- riangle sym-
bol and are prin ed on a grey back-
ground.
iNotes con aining impor an informa ion
are iden ified by he symbol shown on he
lef . They are bordered by horizon al lines
above and below he ex .

6 720 610 576 GB (02.05)
4
Details of the appliance
1 Details of the appliance
1.1 EC Declaration of Conformity
This appliance is in accordance wi h he applicable
requiremen s of he Gas Appliance Direc ive, Boiler Effi-
ciency Direc ive, Elec romagne ic Compa ibili y Direc-
ive and he Low Vol age Direc ive.
1.2 Standard package
• Gas condensing combina ion boiler for cen ral hea -
ing and domes ic ho wa er
• Wall moun ing frame
• Clamp for securing flue duc ki
• Fixings (screws e c.)
• Se of documen a ion for appliance
• Pre-plumbing manifold
• Condensa e drain pipe.
1.3 Description of appliance
• Wall-moun ed appliance, si ing no dependen on
room size
• Na ural gas models are low-emission appliances
• Mul ifunc ion display
• Bosch Hea ronic con rol sys em
• Au oma ic igni ion
• Modula ing con rol
• Full safe y sys ems incorpora ing Bosch Hea ronic
wi h flame ionisa ion moni oring, solenoid valves and
empera ure sensors
• Concen ric flue/air duc wi h es ing poin for
CO2/CO
• Regula ed speed fan
•Pre-mix burner
• Tempera ure con rol for cen ral hea ing
• Tempera ure sensor in domes ic ho wa er
• Safe y empera ure limi er in 24 V elec rical circui
• Three-speed cen ral hea ing pump wi h au oma ic
ven
• Relief valve, pressure gauge, expansion vessel
• Flue gas empera ure limi er (105 °C)
• Ho wa er priori y circui
• Mo orised 3-way valve
• Pla e- ype hea exchange
• Condensa e Trap.
PIN CE-0085 BL 0507
Category
UK II2H 3P
Appliance Type C13, C33
Table 1

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Details of the appliance
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1.4 Accessories
• S andard horizon al flue ki a 100 mm ou side
diame er for flues up o 4 m in leng h.
• Flue duc ki s for horizon al (125 mm ou side
diame er) for flue leng hs up o 13 m and ver ical flue
sys ems for flue leng hs u o 15 m. Fi ing ins ruc ions
are sen wi h hese ki s.
•Heaing programmer
•Timer
• Securi y ki .
1.5 Casing dimensions
Fig. 1
13 Manifold assembly
101 Ou er case
103 Facia cover
XS andard Concen ric Horizon al Flue Sys em: min. 310 mm
Al erna ive Concen ric Flue Sys em: min. 250 mm
YS andard Concen ric Horizon al Flue Sys em: 158 mm
Al erna ive Concen ric Flue Sys em: 121 mm
ZS andard Concen ric Horizon al Flue Sys em: 105 mm
Al erna ive Concen ric Flue Sys em: 130 mm
min.
5
min.
5
850
440
395 250
360
861
906
200
30
6 720 610 601-01.1O
101
103
35
X
13
Y
120
Z

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6
Details of the appliance
1.6 Layout of appliance
Fig. 2
4Hea ronic con rol
6Hea exchanger safe y empera ure limi er
6.1 Ho wa er NTC sensor
7Tes ing poin for gas supply pressure
8.1 Pressure gauge
Flue gas empera ure limi er
15 Relief valve
18 Pump
18.1 Pump speed selec or swi ch
20 Expansion vessel
27 Au oma ic air ven
2 Air gas Mixer uni
32.1 Elec rode assembly
36 Tempera ure sensor in CH flow
43 CH flow
63 Adjus able gas flow res ric or
64 Adjus ing screw for min. gas flow volume
88 3-way valve (combi)
8 DHW flow swi ch (combi)
102 Inspec ion window
120 Fixing poin s
221.1 Flue duc
221.2 Combus ion air in ake
226 Fan assembly
2 5 Appliance ype s icker
234 Tes ing poin for combus ion produc s
234.1 Tes ing poin for combus ion air
271 Flue duc
34 Cover pla e for win flue duc connec ion
355 Pla e- ype domes ic ho wa er hea exchanger
358 Condensa e rap
415 Cover pla e for cleaning access
416 Condensa e collec or
417 Clip for fixing ou er case
418 Da a pla e
423 Siphon
8.1
29
98
102
226
234.1
271
416
221.1
221.2
20
43
9
63
358
64
7
355
6.1
417
88
15
4
18
415
6
36
32.1
234
349
120
418
295
6 720 610 576-02.2O
18.1
423
27

6 720 610 576 GB (02.05)
Details of the appliance
7
1.7 Function
Fig. 3
4Bosch Hea ronic con rol
6Tempera ure limi er, hea exchanger
6.1 Ho wa er NTC sensor
7Tes ing poin for gas supply pressure
8.1 Pressure gauge
Flue gas empera ure limi er
13 Manifold
15 Safe y valve
18 Cen ral hea ing pump
20 Expansion vessel
26 Charging valve
27 Au oma ic ven
2 Mixer uni
2 .1 Bi-me allic hermos a for combus ion air compensa ion
30 Burner
32 Flame sensing elec rode
33 Igni er elec rode
35 Hea exchanger wi h cooled combus ion chamber
36 Tempera ure sensor in CH flow
43 CH flow
44 Ho wa er flow
45 Gas inle
46 Cold wa er inle
47 CH re urn
52 Solenoid valve 1
52.1 Solenoid valve 2
55 Fil er
56 Gas valve CE 427
57 Main valve disc
61 Rese bu on
63 Adjus able gas flow res ric or
64 Adjus ing screw for min. gas inle flow volume
6 Con rol valve
84 Mo or
88 3-way valve
0 Ven uri
1 Pressure relief valve
3 Wa er flow regula or
4 Diaphragm
5 Pushrod wi h swi ch cam
6 Microswi ch
7 Valve for ho wa er flow volume
8 Wa er valve
221 Flue duc
226 Fan
22 Inner casing
234 Tes ing poin for flue gas
234.1 Tes ing poin for combus ion air
317 Display
355 Pla e- ype hea exchanger
358 Condensa e rap
423 Siphon
443 Diaphragm

6 720 610 576 GB (02.05)
8
Details of the appliance
1.8 Electrical wiring diagram
Fig. 4
4.1 Igni ion ransformer
6Tempera ure limi er, hea exchanger
6.1 Ho wa er NTC sensor
Flue gas empera ure limi er
18 Pump
32 Flame sensing elec rode
33 Igni ion elec rode
36 Tempera ure sensor in CH flow
52 Solenoid valve 1
52.1 Solenoid valve 2
56 Gas valve CE 427
61 Rese bu on
84 Mo or, 3-way valve
6 Microswi ch, hydraulic swi ch
135 Mas er swi ch
136 Tempera ure con rol for CH flow
151 Fuse, slow 2.5 A, AC 230 V
153 Transformer
161 Link
226 Fan
300 Code plug
302 Ear h connec ion
310 Tempera ure con rol for ho wa er
312 Fuse, slow T 1,6 A
313 Fuse, slow T 0,5 A
314 Connec or for programmer
315 Terminal block for programmer
317 Digi al display
318 Connec or for imer
328 Terminal block for AC 230 V Mains supply
328.1 Link
363 Indica or lamp for burner
364 Indica or lamp for power supply
365 “Chimney sweep” bu on
366 Service bu on
367 ECO bu on
6
9
32
33
36
52.1
52
56
61
230 V
135
25 V
230V/AC
153
136
151 124789
315
161
M
226
300
LNLs
Ns
328
LR
302
310
312
313
314
317
318
363
364 365 366
ECO
367
4.1
328.1
M
6.1
18
96
84
M
6 720 610 576-08.2O
mains supply
r
r
bl
bl
bl
bl bl
oo
o
o
g
g
p
p
p
o - orange g - green bl - black r - red p - purple

6 720 610 576 GB (02.05)
Details of the appliance
9
1.9 Technical data
Units Natural gas Propane
Max. ra ed hea ou pu ne 40/30°C cen ral hea ing
Max. ra ed hea ou pu ne 50/30°C cen ral hea ing
Max. ra ed hea ou pu ne 80/60°C cen ral hea ing
kW
kW
kW
29.1
28.8
27.2
29.1
28.8
27.2
Max. ra ed hea inpu ne kW 27.5 27.5
Min. ra ed hea ou pu ne 40/30°C
Min. ra ed hea ou pu ne 50/30°C
Min. ra ed hea ou pu ne 80/60°C
kW
kW
kW
8.4
8.3
7.4
11.6
11.4
10.5
Min. ra ed hea inpu ne kW 7.6 10.8
Max. ra ed hea ou pu ne , domes ic ho wa er kW 27.2 27.2
Max. ra ed hea inpu ne , domes ic ho wa er kW 27.5 27.5
Maximum gas flow rate – After 10 minutes from lighting
Na ural gas G20 (His = 9,5 kWh/m3)m
3/h 2.9 -
LPG (Hi = 12,9 kWh/kg) kg/h - 2.1
Gas supply pressure
Na ural gas G20 mbar 20 -
LPG mbar - 37
Expansion vessel
Charge pressure bar 0.75 0.75
To al capaci y l 10 10
Hot water specifications
Ho wa er flow ra e (fac ory se ing) l/min 8 8
Max. ho wa er flow ra e l/min 14 14
Ou le empera ure range °C 40 - 60 40 - 60
Max. permissible wa er supply pressure bar 10 10
Min. inle pressure bar 0.2 0.2
Specific flow ra e l/min 12.4 12.4
Flue
Flue gas emp. 80/60°C, ra ed/min. load °C 67/55 67/55
Flue gas emp. 40/30°C, ra ed/min. load °C 43/32 43/32
Residual delivery pressure
(inc. pressure drop in air in ake duc ) Pa 80 80
CO2 level a max. ra ed hea ou pu
CO2 level a min. ra ed hea ou pu
%
%
9.5
9.2
11.3
11.0
NOx-class 5 5
SEDBUK figure, Band A % 90.6 90.6
Condensate
Max. condensa ion ra e ( R = 30°C) l/h 2.3 2.3
pH-value, approx. 4.8 4.8
General Data
Elec rical power supply vol age AC ... V 230 230
Frequency Hz 50 50
Max. power consump ion W 101 101
Noise ou pu level dB(A) 36 36
Appliance pro ec ion ra ing IP X4D X4D
Max. CH flow empera ure °C nom. 90 nom. 90
Max. permissible opera ing pressure (CH) bar 2.5 2.5
Permissible ambien empera ures °C 0 - 60 0 - 60
Nominal capaci y of appliance l 3.75 3.75
Weigh (excluding packing) kg 46 46
Table 2

6 720 610 576 GB (02.05)
10
Details of the appliance
Condensate analysis, mg/l
Flue system
Elbow - 90 ° Bend - 45 °
Equivalen leng h 2 m Equivalen leng h 1m
Gas supply
Domestic water performance
Ammonium 1.2 Nickel 0.15
Lead ≤ 0.01 Mercury ≤ 0.0001
Cadmium ≤ 0.001 Sulpha e 1
Chromium ≤ 0.005 Zinc ≤ 0.015
Halogena ed
hydrocarbons ≤ 0.002
Tin ≤ 0.01
Hydrocarbons 0.015 Vanadium ≤ 0.001
Copper 0.028 pH-value 4.8
Table 3
HORIZONTAL 100 mm – Standard
Overall Diame er of Duc mm 100
Max.
4m
Flue Terminal / Duc Assem-
bly Leng h
mm 750
Ex ension Duc Leng h mm 1000
Table 4
ALTERNATIVE HORIZONTAL 125 mm FLUE SYSTEM
Overall Diame er of Duc mm 125
Max.
13 m
(inclu-
ding
urre )
Flue Terminal / Duc Assembly mm 550
Ex ension Duc Leng h - Fixed mm 200
Ex ension Duc Leng h - Fixed mm 450
Ex ension Duc Leng h - Fixed mm 950
Ex ension Duc Leng h - Fixed mm 1950
Ex ension Duc Leng h -
Telescopic
mm 265-
375
Ex ension Duc Leng h - Adjus a-
ble (Cu o leng h)
mm 200
Table 5
VERTICAL 125 mm FLUE SYSTEM
Overall Diame er of Duc mm 125
Max.
15 m
Flue Terminal / Duc Assembly mm 1360
Ex ension Duc Leng h mm 200
Ex ension Duc Leng h - Fixed mm 450
Ex ension Duc Leng h - Fixed mm 950
Ex ension Duc Leng h - Fixed mm 1950
Ex ension Duc Leng h - Tele-
scopic
mm 265-
375
Ex ension Duc Leng h -
Adjus able (Cu o leng h)
mm 450
Table 6
Total length of gas supply pipe
(metres)
Pipe diameter
(mm)
369
Gas discharge ra e (m3/h)
8.7 5.8 4.6 22
18.0 12.0 9.4 28
Table 7
Domes ic
Wa er Flow
Ra e l/min
Tempera ure
Rise
30 °C 13.2
Tempera ure
Rise
35 °C 11.3
Tempera ure
Rise
40 °C 9.9
Maximum Mains pressure bar 10.0
Minimum Mains pressure bar 0.2
Table 8

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Installation regulations
11
2 Installation regulations
Gas Safe y (Ins alla ion & Use) Regula ions 1998: All
gas appliances mus be ins alled by a compe en per-
son. Failure o ins all correc ly could lead o prosecu-
ion.
The manufac urers no es mus no be aken, in any way,
as overriding s a u ory obliga ions.
The appliance mus be ins alled in accordance wi h he
curren IEE Wiring Regula ions, local Building Regula-
ions, Building S andards (Sco land) (Consolida ion),
bye-laws of he local Wa er Company, Heal h and
Safe y Documen 635 (Elec rici y a Work Regula ions
1989) and any o her local requiremen s.
Produc Liabili y regula ions indica e ha , in cer ain cir-
cums ances, he ins aller can be held responsible, no
only for mis akes on his par bu also for damage resul -
ing from he use of faul y ma erials. We advise he
ins aller o avoid any risk by using only quali y approved
branded fi ings.
The relevan Bri ish S andards should be followed i.e.
• BS 6798: Specifica ion for he ins alla ion of gas
fired ho wa er boilers of ra ed inpu no exceeding
60kW
• BS 5449: Cen ral Hea ing for Domes ic Premises
• BS 5546: Ins alla ion of gas ho wa er supplies for
domes ic purposes
• BS 5440:1: Flues and ven ila ion for gas appliances
of ra ed inpu no exceeding 70 kW (gross): Flues
• BS 5440:2: Flues and ven ila ion for gas appliances
of ra ed inpu no exceeding 60 kW (gross): Air
Supply
• BS 6891: Ins alla ion of low pressure gas pipework
ins alla ions up o 28mm (R1).
• BS 7074:1: Code of prac ice for domes ic hea ing
and ho wa er supply.
These instructions must be followed.
3 Installation
3.1 Important remarks
BAppliance should only be ins alled in sealed cen ral
hea ing sys ems.
BTo avoid gas forma ion in he sys em, galvanised radi-
a ors or pipes mus no be used.
BIf a room hermos a is used: do no fi a hermos a ic
radia or valve on he radia or in he primary room.
BAdd a sui able an i-freeze fluid compa ible wi h alu-
minium o he wa er in he cen ral hea ing sys em.
Sui able produc s are available from Be z-Dearborn
Tel.: [phone] and Fernox Tel.: 01799
550811.
BIn our experience, he addi ion of sealing agen s o
he wa er in he cen ral hea ing sys em can cause
problems (deposi s in he hea exchanger). For ha
reason we advise agains heir use.
BAlways urn off he gas cock before car-
rying ou any work on componen s
which carry gas.
iFixing of he appliance, gas and flue con-
nec ions, commissioning of he sys em
and elec rical connec ions may only be
carried ou by compe en persons au hor-
ised by CORGI.

6 720 610 576 GB (02.05)
12
Installation
3.2 Domestic hot water
Any regula ions specified by he local wa er company
mus be observed.
The final 600 mm of he mains cold wa er connec ion o
he applaince should be made in copper ube only.
The appliance is sui able for a mains supply having a
maximum pressure of 10 bar. A pressure reducing valve
mus be fi ed, if necessary.
The ho wa er ou le empera ure is se o be capable of
achieving a maximum of 60°C. The maximum empera-
ure and he frequency of he recharge of he hea s ore
may be rese .
The maximum wa er flow ra e is fac ory se a 9.9 l/min
o give empera ure rise of 40°C. If a higher rise is
required hen he flow mus be reduced a he ap and
he discharge empera ure will rise up o he maximum
se figure.
The empera ure rise, up o he maximum se by he user,
is au oma ically main ained by he modula ion of he
hea inpu . In win er, when he mains empera ure is very
low, he wa er flow, adjus ed a he ap or shower,
should be reduced o main ain he required delivery
empera ure.
I is sugges ed ha long pipe runs o aps or showers
be insula ed o preven he rapid cooling of he wa er.
All ypes of single lever mixer aps and hermos a ic
mixer uni s sui able for a mains pressure of up o 10 bar
can be used.
The head of a loose-head shower mus no be allowed
o fall wi hin 25 mm of he op he ba h o preven he
risk of wa er being drawn back in o he mains. Al erna-
ively he shower mus be fi ed wi h an an i-syphonage
device a he poin of he flexible hose connec ions.
Over-rim bide s may be connec ed o he appliance pro-
vided ha i is in accordance wi h he requiremen s of
he local wa er company. The ou le (s) should be
shrouded and unable o have any emporary hand held
spray a ached. No an i-syphonage arrangemen s are
necessary.
In excep ionally hard wa er areas a device o preven
scale forma ion may be fi ed or, al erna ively, he maxi-
mum empera ure rese o abou 45°C which may
reduce he risk of scale forma ion. The ins alla ion of a
scale inhibi or assembly should be in accordance wi h
he requiremen s of he local wa er company. Ar ificially
sof ened wa er mus no be used o fill he cen ral hea -
ing sys em. An isola ing valve should be fi ed o allow
for servicing.
Devices, such as water meters or back-flow preven-
tion valves, capable of preventing the flow of expan-
sion water must not be fitted unless separate
arrangements have been made.
A Zilme Z160 expansion vessel is he preferred ype. A
hread sealan compa ible wi h po able wa er mus be
used.
3.3 Sealed systems
The appliance mus no be opera ed wi hou he sys em
being full of wa er, properly ven ed and pressurised.
The expansion vessel has a volume of 10 li res and is
charged o a pressure of 0.75 bar.
The wa er capaci y of he sys em is shown in able 11,
page 26. If a grea er capaci y is required hen an addi-
ional expansion vessel mus be fi ed in o he sys em
re urn as close o he appliance as possible. The sys em
pressure can be se up o a maximum of 1.5 bar wi h 1
bar being he normal se ing.
If he sys em pressure is grea er han 2.65 bar when he
appliance is opera ing a maximum empera ure hen an
addi ional expansion vessel mus be fi ed in o he sys-
em re urn as close o he appliance as possible.
The filling poin mus be a low level and arranged as
shown in figs. 5 and 6.
The pressure relief valve is se o opera e a 3 bar.
There mus be no connec ion o he mains wi hou he
approval of he local wa er company. All connec ions in
he sys em mus be capable of wi hs anding a pressure
of up o 3 bar and he radia or valves conform o he
requiremen s of BS 2767:10.
If Thermos a ic Radia or Valves are fi ed hen i is rec-
ommended ha one radia or is lef open.
Repea ed ven ing probably indica es a leak and his
mus be rec ified o ensure he proper opera ion of he
appliance.
No galvanised radiators or pipes must be used.
If any system water treatment is required then only
products suitable for use with Aluminium shall be
used i.e Fernox- Copal or Sentinal X100, in
accordance with the manufacturers instructions.
The use of any other substances will invalidate the
guarantee. The pH value of the system water must
be less than 8 or the appliance guarantee will be
invalidated.
A drain cock o BS2879 mus be fi ed o he lowes
poin of he sys em.
IMPORTANT: Check that no dirt is left in the water
pipework as this could damage the appliance.
Thoroughly flush the heating system and the mains
water supply before fitting the appliance to the wall
in accordance with the recommendations of
BS75 3:1 2.

6 720 610 576 GB (02.05)
Installation
13
Fig. 5 Sealed primary water system
Fig. 6 Sealed primary water system - filling meth d
3.4 Siting the appliance
Regulations concerning the Installation Site
BRelevan na ional regula ions mus be complied wi h
sec ion 3.9.1.
BConsul he ins alla ion ins ruc ions for de ails of min-
imum clearances required.
Combustion air
In order o preven corrosion, he combus ion air mus
no con ain any corrosive subs ances.
Subs ances classed as corrosion-promo ing include
halogena ed hydrocarbons which con ain chlorine and
fluorine compounds and are con ained in some sol-
ven s, pain s, adhesives, aerosol propellan s and house-
hold cleaners, for example.
Surface temperature
The max. surface empera ure of he casing and he flue
is less han 85 °C.
This means ha , no special safe y precau ions are
required wi h regard o flammable building ma erials
and fi ed furni ure. The specified clearences mus be
main ained.
Cupboard/Compartment
The appliance can be ins alled in a cupboard/compar -
men need for airing clo hes providing ha he require-
men s of BS6798 and BS5440:2 are followed. The low
casing losses from he appliance elimina e he need for
ven ila ion openings in he compar men .
Domestic
hot water Central heating flow Radiator
valve
Lockshield
valve
Central heating return
A drain cock should be fitted at
the lowest point of the heating
circuit and the appliance
Water
main
BS stop valve.
Fixed spindle type
APPLIANCE
Refer to Fig.1
Appliance
water flow
diagram
WRC approved
filling loop
6 720 610 576 -09.2O
Heating
return
Non-return
valve
Non-return
valve
Hose
union
Hose
union
Test
cock
Temporary hose
Test
cock
6 720 610 576 - 10.1O

6 720 610 576 GB (02.05)
14
Installation
3.5 Wall mounting frame assembly
BTake he wall moun ing frame ou of he package and
screw oge her wi h 6 screws as shown in fig. 7. Use
he inner lugs on he op and bo om horizon al
sec ions for he appliances ha are 440 mm wide.
Fig. 7
BHold he wall-moun ing frame agains he wall
ensuring ha i is ver ical.
BMark he posi ion of he flue duc hole if a rear flue is
o be used. Refer o fig. 1 and 15.
BMark he holes for he wall moun ing frame on o he
wall, drill and plug he holes and screw he wall
moun ing frame o he wall wi h he screws provided.
Fig. 8
BScrew he pre-plumbing manifold wi h wo screws o
he wall moun ing frame.
Fig. 9
3.6 Pre-piping the system
Fig. 10 Manif ld
43 CH flow
47 CH re urn
112 Gas cock
171 Domes ic ho wa er
172 Cold wa er relief
BA drain ap should be fi ed a he lowes poin of he
cen ral hea ing sys em.
BWRc filling loop mus be fi ed.
6 720 610 576-04.1O
6 720 610 576-05.1O
6 720 610 576-11.1O
200
260
6 720 610 576-06.1O
35
120-130
50
4743
172112
171

6 720 610 576 GB (02.05)
Installation
15
Condensate drain
Prepare he condensa e discharge sys em. Refer o
fig. 11. The condensa e drainage pipe should be a
s andard drain pipe ma erial , i . e. PVC, PVC-U, ABS
e c. and should be a leas 22 mm in diame er.
A siphon wi h a 75 mm condensa e seal is fi ed wi hin
he appliance.
A connec ion o an in ernal drain is recommended.
Any ex ernal drain pipe should be insula ed o preven
freezing.
The connec ion of a condensa e pipe o a drain may be
subjec o local building regula ions.
For more informa ion refer o he CIBSE Guide,
BS5546 and he Building Regula ions.
Fig. 11 P siti n f the c ndensate drain
3.7 Fitting the appliance
BRemove packing, aking care o observe he ins ruc-
ions on he packing.
BLie he boiler on i s back.
Removing the outer case
BTurn he clips wi h a screwdriver (1.).
BSlide he ou er case upwards and hen forwards o
remove (2.).
BRemove he plas ic caps from he boiler connec ions.
Fig. 12
Fixing the appliance
BFi he washers on o he gas and wa er connec ions.
BLif he boiler on o he wall-moun ing frame. The lugs
pass hrough he rec angular holes in he boiler back
panel.
BTake care no o dis urb he washers on he connec-
ions.
6 720 610 602 - 03.1O
Benchmark: For op imum performance
af er ins alla ion, his boiler and i s asso-
cia ed cen ral hea ing sys em mus be
flushed in accordance wi h he guide-
lines given in BS5793:1992 “Trea men
of wa er in domes ic ho wa er cen ral
hea ing sys ems”.
iThe ou er case is secured agains unau-
horised removal by wo clips (elec rical
safe y).
Always secure he ou er case wi h hose
clips again af er refi ing.
1.
2.
6 720 610 332-07.1R

6 720 610 576 GB (02.05)
16
Installation
Connecting the flue duct
BFi flue duc connec or on o appliance flue spigo .
BSecure wi h he wo screws supplied.
Fig. 13
BFor remaining ins alla ion of flue assembly, refer o
he relevan ins alla ion ins ruc ions.
3.8 Checking the connections
Water connections
BCheck ha he O-rings or seals are in place before
igh ening he connec ion.
BTurn on he service valves for cen ral hea ing flow
and re urn and fill he hea ing sys em hrough a WRC
approved filling loop.
BCheck all seals and unions for leaks ( es ing pressure
max. 3.0 bar as indica ed by pressure gauge).
BTurn on cold wa er service cock and fill ho wa er sys-
em ( es ing pressure max. 10 bar).
BCheck all connec ions for leaks.
Gas supply pipe
BCheck ha he seal is in place before igh ening he
connec ion.
BTurn off gas cock o pro ec gas valve agains
damage from excessive pressure.
BCheck gas supply pipe.
BRelease he pressure on he gas supply pipe.
3.9 Flue Systems
The only flue sys ems ha may be used are hose sup-
plied by Worces er Hea Sys ems.
The flue sys em mus be ins alled in accordance wi h
he requiremen s of BS5440:1.
Standard 100 mm flue system
The s andard concen ric flue sys em provides for a hor-
izon al leng h of up o 4 m. Full ins ruc ions for fi ing his
flue are in Subsec ion 3.9.2 “Ins alla ion of he flue”.
Alternative 125 mm diameter flue systems
Ins alla ion ins ruc ions for he al erna ive flue sys ems
are sen wi h he appropria e flue ki .
Sys ems are available o give a maximum horizon al
leng h of 13 m.
A ver ical flue sys em up o a heigh of 15 me res is avail-
able.
45° and 90° flue bends can be used wi h a correspond-
ing reduc ion in flue leng h of 2m for each 90° bend and
1 m for each 45° bend used.
IMPORTANT: Any horizon al flue sys em fi ed o a con-
densing boiler mus incline owards he appliance a an
angle of 3 % (30 mm per me re leng h) o preven con-
densa e dripping from he flue erminal. This means
that the clearance above the appliance must be
increased to match the duct length.
Refer to fig. 1 on page 5.
6 720 610 332-09.1R
1
3
2
4

6 720 610 576 GB (02.05)
Installation
17
3.9.1 Siting the Flue Terminal
The flue mus be ins alled in accordance wi h
BS 5440:1 and he Building Regula ions. Flue erminals
in carpor s and under balconies are o be avoided.
The erminal mus be posi ioned so ha i does no
cause an obs ruc ion nor he combus ion produc s a
nuisance. See fig. 14 and able 9.
The erminal will, a imes, give ou a plume of wa er
vapour and considera ion mus be given o his when
choosing a erminal posi ion. Keep clear of securi y
ligh ing, ac iva ed by passive infra-red sensing heads.
If he erminal is less han 2 m above a surface o which
people have access hen a guard mus be fi ed. The
guard mus be evenly spaced abou he erminal wi h a
space of 50 mm in each direc ion and fixed wi h pla ed
screws.
A guard Type K2 for he s andard horizon al flue, can be
ob ained from Tower Flue Componen s, Vale Rise, Ton-
bridge TN9 1TB.
Fig. 14
Minimum dimensions of flue terminal positions (all types) (see fig. 14)
Dimension Terminal Position (kW input expressed in net) alanced flues room sealed: Fanned draught
A1) Direc ly below an opening, air brick, opening windows, e c. 300 mm
B 1) Above an opening, air brick, opening window, e c. 300 mm
C 1) Horizon ally o an opening, air brick, opening window, e c. 300 mm
D Below gu ers, soil pipes or drain pipes 75 mm
E Below eaves 200 mm
F Below balconies or car por roof 200 mm
G From a ver ical drain pipe or soil pipe 150 mm
H From an in ernal or ex ernal corner 300 mm
I Above ground roof or balcony level 300 mm
J From a surface facing he erminal 600 mm
K From a erminal facing he erminal 1200 mm
L From an opening in he car por (e. g. door, window) in o he dwelling 1200 mm
M Ver ically from a erminal on he same wall 1500mm
N Horizon ally from a erminal on he same wall 300 mm
O From he wall on which he erminal is moun ed No applicable
P From a ver ical s ruc ure on he roof No applicable
Q Above in ersec ion wi h roof No applicable
Table 9
1) In addi ion, he erminal should no be nearer han 150 mm (fanned draugh ) o an opening in he building fabric formed for he pur-
pose of accommoda ing a buil -in elemen such as a window frame.

6 720 610 576 GB (02.05)
18
Installation
3.9.2 Installation of the flue
The s andard 100 mm diame er horizon al flue sys em is
sui able for leng hs up o 4 m.
Flues up o 650 mm do no require an ex ension duc
assembly.
Flues be ween 1600 mm and 4000 mm require ex en-
sion duc assemblies.
NOTE: Flue leng hs be ween 650 mm and 730 mm
canno be accomoda ed. Refer o fig. 16, 17, 18.
S andard sys em comprise: Flue urre - Flue urre
clamp - Terminal assembly - Wall sealing - pla es.
Ex ension ki comprises: Air duc - Flue duc - Duc
clamp. Refer o fig. 19.
Ins ruc ions for fi ing o her flue sys ems are packed
wi h he relevan flue ki .
Check ha he posi ion chosen for he appliance is sa -
isfac ory Refer o fig. 15.
Fig. 15 Marking the p siti n f the side flue pening
Fig. 16 Standard Flue
Appliance
120
Drilling point for
flue duct opening
3 %
(30 mm/meter)
Centre
line of
flue
opening
and
appliance
Centre line of
flue/air duct
Top of the
wall
mounting
frame
H
H
Standard Horizontal Flue 158 mm
Optional Horizontal Flue 121 mm 6 720 610 602 - 07.1O
Flue
Turret
No
Clamp
Maximum 650 mm
Terminal
Assembly
Outer
Wall
6 720 610 602 - 08.1O

6 720 610 576 GB (02.05)
Installation
19
Fig. 17 Flue with ne extensi n
Fig. 18 Flue with extensi ns
Fig. 19 Flue c mp nents
Maximum 1600mm
Flue
Turret
No
Clamp
Terminal
Assembly
Outer
Wall
Extension
Duct
6 720 610 602 - 09.1O
Clamp
Flue
Turret
No
Clamp
Clamp
Extension
Duct
Clamp
Extension
Duct
Terminal
Assembly
Outer
Wall
6 720 610 602 - 10.1O
Extension Air Duct
Extension Flue Duct
Terminal Assembly
Duct Clamp
Wall Sealing Plates
6 720 610 602 - 11.1O
Flue
Turret

6 720 610 576 GB (02.05)
20
Installation
3.9.3 Flue duct preparation and assembly
Measure he flue leng h L. Refer o fig. 20, 21.
Fig. 20 Flue length - rear
Fig. 21 Flue length - side
Mark off he leng hs shown on o he duc s and cu o
leng h. The cu s mus be square and free from burrs.
Terminal assembly ou er (air) duc - L-70 mm, inner
(flue) duc - L- 50 mm.The measuremen is made from
he ridge a he erminal indica ing he ou er face of he
wall. Refer o fig. 22.
Ex ension air duc - L-70mm, flue duc - L-50 mm.
The measuremen is from he formed end.
Fig. 22 Flue terminal p siti n
Assemble flue sys em comple ely. Push he duc s fully
oge her and clamp in he posi ions. The slope of he
erminal ou le mus face downwards.
The assembly will be made easier if a solven free
grease is ligh ly applied i.e Vaseline, o he male end of
he duc s.
NOTE: An inner wall sealing plate is provided which
should be fitted to the ducts before assembly.
Push he assembly hrough he wall and fix he urre o
he appliance wi h he clamp. Refer o fig. 23.
Fig. 23 Flue turret
Ensure ha he urre is fully en ered in o he socke on
he boiler. From he ou side fix he ou er wall pla e o he
erminal and, af er ensuring he duc is properly i nclined
owards he boiler, fix he pla e o he wall.
If he erminal is wi hin 2 m of he ground where here is
access hen an approved erminal guard mus be fi ed.
The guard mus give a clearance of a leas 50 mm
around he erminal an be fixed wi h corrosion resis an
screws.
NOTE: THE FLUE MUST BE INCLINED T O THE
BOILER
L
120
6 720 610 602 - 12.1O
NOTE: THE FLUE MUST BE INCLINED T O THE
BOILER
L
6 720 610 602 - 13.1O
Outer
Wall
Face Flue Terminal
Raised Ring
locating the
terminal relative
to the outside
wall face
6 720 610 576 - 20.1O
Air and
Flue Duct
Entry into
silicone
rubber seals
Flue Turret
Clamp
Flue Socket
on Boiler 6 720 610 602 - 14.1O