Bosch Worcester 240 Combi OF User guide

....--~~~ORCESTER-----.
BOSCH
240 Combi OF
WALL MOUNTED COMBINATION BOILER FOR CENTRAL HEATING AND
MAINS FED DOMESTIC HOT WATER
INSTALLATION AND
SERVICING INSTRUCTIONS
GC NUMBER 47 311 09
BOILER OUTPUT
Automatic Modulating Control
To Domestic Hot Water and Central Heating
Minimum 9.2 kW (31 ,400 Btu/h)
Maximum 24.0 kW (82,000 Btu/ h)
IMPORTANT: THIS APPUANCE IS FOR USE WITH NATURAL GAS ONLY
THESE INSTRUCTIONS APPLY IN THE UK ONLY
THESE INSTRUCTIONS ARE TO BE LEFT WITH THE USER OR AT THE GAS METER

Contents
1. Installation Requirements .... ..... ........ . ................. . ......... Page 2
2.
General Information .... . .. ........ ... .................................. .. Page 2
3.
Technical Data ................ .. . ...... ........... ..... .................. ..... Page 4
4.
Siting the Appliance .............................. . ....................... Page 5
5.
Siting the Flue Terminal .................. .. ...... ............. .... . .... Page 6
6.
Air Supply .... ........................................................ .. ... .. .... Page 6
7.
Sealed System .................................... .. ...... .. ...... .. .... ...... Page 7
8.
Open Ven t Pr im ary Water System ...... ............... ......... Page 8
9.
Domestic Hot Water .............................. . .. .. .... ............... Page 8
1. Installation Regulations
1.1 Gas Safety (Installation and Use) Regulations 1984
All gas appliances must be installed by a competent person in
accordance with the above regulations. Failure to install appli·
ances correctly could lead to prosecution.
1.2
The manufacturers notes must no t be taken ,i n any way ,as
overrid ing statutory obligations.
1.3
The compliance with a British Standard does not. of itself. con ·
fer immunity from legal obligations. In particular the installation
of this appliance must be in accordance with the relevant require ·
ments of the Gas Safety (Install ati on and Use) Regulations 1984 as
amended, current
lEE Wiring Regulations, local Building Regu la ·
tions, Building Standards ( ScotlandXConsolidation) and byel a ws of
the local Water Company . Health and Safety Document No . 635
(
Electridty at Work Regulat ions ). !t should be in accordance w ith
the relevant recommendations of the f ollowing B ritish Standards.
BS 6798:1987 Specifi cati on for installati on ofgas fired hot water
b
oilers of rated input no t exceeding 60 kW.
BS 5449 :19 90 Centra l Hea t ing for Domestic Premises.
BS 5546:1990 Installation of gas hot water supp li es for domes·
tic purposes.
BS 5440 :1 :1990 Flues and Ven tilati on for gas appliances of rated
in put not exceedi ng 60 kW: Flues .
BS 5440:2:1989 Flues and Ventilation for gas appliances of rated
input not exceeding
60kW : Air Supply.
BS 6891 :1988 Installa ti on of l ow pressure gas pipework installa·
t ions up to 28 mm (R 1).
1
.4 To ensure that the installation will perform to the highest
standards, t
he system and components should conform to any
other relevant
Br itish Standards in addition to those mentioned
in the instructions.
2. General Information
2.1 This appliance is not suitable for external installation.
2.2
The appliance controls are set to provide a maximum
output
for the domestic hot water of 24 kW and a central
heating load
of up to 16 .1 kW .
2.3 The appliance has a permanent pilot.
2.4 PRINCIPLE APPLIANCE COMPONENTS See Fig . 1.
A
low thermal capacity Gas to Water heat exchanger.
A
Water to Water heat exchanger to provide domest ic hot water.
Fully modulating controls in the central heating and domes tic
ho t water modes of operation.
An expansion vessel, pressure gauge and pressure relief valve .
A
by ·pass for the central heati ng system.
Temperature safety cut·out controls.
Awater
flow regulator.
2
10. Electrical .......... .. ..... ... ....... .... . ...... .. .... ..................... ........ Page 10
11 . Installation ........ .. ...... .... .... .. ...... . ...... ................ .... .. .. ...... Page 13
12 . Commissioning .. .... .. ............... .. .................. ...... .. .... .. ..... Page 15
13. Instructions to the User ........................................... ... .. Page 16
14 . Inspection and Servidng .......... .......................... ........ ..Page 17
15 . Replacement of Parts ..... . .. .. . ........................... ... .. .... . .... Page 19
16 . Short Parts List ... ............... .... .......................... .... . .... .....Page 25
17 . Operational Flow Diagram . .. ......... .. .... .. .. ... .............. . .... Page 26
18.
Fault Finding . .. . ... . ... . ........ ..... ..................... .. .............. .. ... Page 28
An optional facia mounted programmer instead of the standard
Operating
Switch .
2.5 ELECTRICAL SUPPlY
Mains supply: 240V -, 50 Hz, 150 watts. External fuse 3A.
Internal fuses: T2A (F1) and T315mA (F 2).
2.6 GAS SUPPLY
The boiler requires 2. 82 m' /h (9 6.8 ft '/hr) of gas. The gas meter
and supply pipes must be capable
of supplying this quantity of
gas in addition to the demand from an y other appliances being
served.
The table below gi ves an i nd icati on of limiting gas pipe
lengths and the allowance to be made for fittings.
Refer to
BS6891 f or further information.
The meter gov ernor should deliver a dynamic pressure of 20
mbar (B in wg .) at the appliance.
The complete installation, includ i ng the gas meter, must be test·
ed for soundness and purged. Refer to BS 6891 .
TOTAL LENGTH OF
GAS SUPPLY PIPE (metres) Pipe
Diamet er
3 6 9
(mm)
Gas Discharge Rate (m3 /h)
2.9 - - 15
8.7 5.8 4.6
22
18.G 12.0 9.4 28
Note:
Each fitting used in the gas line from the meter is equivalent to a
length of straight p ipe which mus t be added to the straight pipe
length to give the total length .
ie : Elbow = 0.5 metres, Tee = 0.5 metres, 90 ° Bend = 0.3 metres.
2.7 GENERAL INSTALLATION
The appliance: is supplied for connec tion to a sea led system but
is suitable for use with an open vent system. The connections
are suppl
ied as an option al kit.
The spec ified vent il a ti on openings must not be ob st ruc te d.
Do not pla ce anything on top of the appliance.
The clearances specified for servici ng must be maintai ned .
2.8 FLUE
The flue mu st be generally verti cal and have no horizontal runs.
The flue must end with a British Gas approved term i nal.
2.9 CONTROLS
T he electronic control system and gas valve modulate the heat
input
in response to t he central heati ng and domestic hot water
temperature settings between minimum and
max imum.
The Operating Switch provides for the selecti on of domestic hot

Fig. 1. Appliance water flow diagram.
Automat ic air vent
Gas to Water
heat exchanger
Waterflow
man i fold
L_
Ce n tra l hea ri ng
by · pass ad j uster
t__ - - ..
Boile r
- - -- - Water div erter
v alve
---,-- -:
I
I
Pr ess u re reli ef v al ve
- Oo mes t oe hot wate rout
-- Ma i ns col d water in
-
Ce nt ra l he at i ng retu rn
-- Cen tra l he at i ng flow
water only (WATER) or central heating and domestic hot water
(HEATING & WATER) or OFF .
A fac ia mounted programmer is ava ilable as an optional extra. A
remote mounted prog rammer may be connected to the appli-
ance.
The integral fac ia displays i nd icate the status of the appliance.
There is
prov ision for the connection of a mains voltage room
thermostat and/or a frost thermostat.
The electronic controls prevent rapid cycling of the appliance in
the central heating mode.
2.1 0
SYSTEM NOTES
WARNING
Check that no dirt is left in either the gas and water pipework
as this could cause
damage to the appliance. Thoroughly flush
the heating system and the cold water mains supply. Purge
the gas supply before finally connecting theappliance ..
The water pipe connections throughout a sealed system must
be capable
of sustaining a pressure of upto 3 bar.
Radiator valves must conform
to the requirements of BS2767
(10) : 1972 .
The relief valve discharge must be directed away from any elec -
trical components or where it would cause a hazard to the user.
Adrain cock to BS 2879 must be fitted to the lowest point of the
system.
For circu it design purposes it is important that due note is taken
of the informati
on gi ven in Table 3 relating to the available
pump head.
3
2.11 SHOWERS, BIDETS, TAPS AND MIXING VALVES
Hot and cold taps and mixing valves used in the system must
be suitable for operating at a mains pressure of up to 10 bar.
Thermostatically controlled or pressure equalising shower
valves will guard against the
flow of water at too higb a temper-
ature. I
Hot and cold mains fed water can be supplied direct to an over-
rim flushing bidet subject to local Water Company requirements.
With all mains fed systems the flow of water from the individual
taps will vary with the number
of outlets operated simultane-
ously and the cold water mai ns supply pressure to the property.
Flow balancing using 'Ball - o-Fix' type valves is recommended to
avoid an excessive reduction in flow or even starvation to indi -
vidual outlets. For further information contact Worcester Heat
Systems
Ltd .
2.12 SAFETY CONSIDERATIONS
The appliance must not be operated in a waterless condit ion .
The appliance must not be operated wi th the boiler inner casing
cover removed.
Work must not be carried out on the appliance without the gas
and electricity supplies
be i ng switched off .
Checks must be made to ensure that the ventilation openings
made into
walls and partitions are of the correct size and are not
obstructed.
2.13 OPERATION
Domestic Hot Water: With a demand for hot wa ter the burner
will light at its maximum setting and then automatically adjust
its output to maintain the temperature rise of the delivered
water.
When hot water is no longer required, the burner will
extinguish. The pump will continue to run for a short period to
dissipate the residual heat from the appliance.
Central Heating: With a demand for heating the burner will light
at its min i mum setting and gradually increase to give the maxi -
mum output. The output of the appliance is then automatically
adjusted to maintain the temperature
of the system. The output
can reduce down to a minimum of ?.2
kW. If the system no
longer requires even the minimum output to maintain the
desired
room temperature the burner will extinguish. The pump
will continue to run to dissipate the residual heat from the appli -
ance. The appliance will remain off for a fixed period of two min -
utes before re -lighting to automatically meet the system require-
ments.
Domestic Hot Water
and Central Heating: The ·appliance will
supply heat to the central heating system as required. A
demand for domestic hot water at a tap or shower will override
the central heating requirement
for the period of the domestic
hot water demand.
When hot water is no longer required the
burner will extinguish and the appliance will return to the cen -
tral heating state and its normal mode of operation. The pump
will continue to run to dissipate the residual heat from the appli·
ance as necessary.

3. Technical Data
The Data Plate is fixed to the control box casing.
TABLE 1
TABLE 5
NOMINAL BOILER RATINGS
OUtput Input
Burner Setting
Gas Rate
Pressure
Flue Di ameter
125mm
kW Btu/h kW Btu /h
mbar. in . wg . m3/h
tt
3/h
9.2 31 , 400 12 .6
43,000
2.7 1.1
1.17 40.2
Flue Pipe
BS 4543
16 .1
54 , 900 212 72,300 73 2.9 2. 03 69 .6
24 .0
82,000
30 .1
102,700
15 .0 6.0 2. 82
96 .8
TABLE2
AVAILABLE PUMP HEAD
Boiler Output
Head
Min. Flow Rate Temp . rise across
kW Btu /h
metres
feet
litres/min
gal / min
heating flow
and return
9.2 31 , 400 4.9 15 Q
120
2. 64
11 •c ( 20"FJ
16 .1 54 ,9 00 2. 54
8. 25 23.0 5. 07
11 •c (20"FJ
24 .0
82 , 000 2.0 6.5
23.0 5. 07 15 °C { 28 °F)
TABLE 3
SPECIFICATIONS
CENTRAL HEATING FLOW FriTING 22
mm Compression
CENTRAL HEATING RETURN FmiNG 22
mm Compression
COLD WATER MAINS INLET FrrnNG 15
mm Compression
DOMESTIC HOT WATER OUTLET FmiNG
15 mm Compression
GAS INLET FrrnNG Rc 1'2
PRESSURE RELIEF VALVE DISCHARGE FriTING 15
mm Compression
CASING HEIGHT
900 mm (35.4 in.)
CASING WIDTH
450 mm (17 .7 in.)
CASING DEPTH
360 mm (14.2 in.)
WEIGHT (including water) 48 kg (10Sib)
INSTALLATI ON WE IGHT 46 kg (101 lb)
PACKAGED WEIGHT 49 kg (1 08 lb)
TABLE4
SPECIFICATIONS
PRIMARY WATER CAPACITY 2.7 litres (0 .6 galls.)
MAXIMUM
COLD SUPPLY PRESSURE 10 Bar (1 50 psi)
MINIMUM
COLD SUPPLY PRESSURE (WORKING) FOR MAXIMUM HOT WATER FLOW
1.6 Bar (23.5 psi)
MINIMUM
COLD SUPPLY PRESSURE (WORKI NG ) TO OPERATE THE APPLIANCE 0.6 Bar (9 psi)
MAXIMUM
CENTRAL HEATING FLOW TEMPERATURE Nominally 82°C (180°F)
MAXIMUM STATIC HEAD (PRIMARY)
25 metres ( 81 ft)
MIMIMUM STATIC HEAD (PRIMARY) 0.3 me tr es (1 ft)
OUTPUT TO DOMESTIC HOT WATER Modulating 9. 2-24 .0 kW
(31 ,40Q-82,000 Btu /h)
OUTPUT TO CENTRAL HEATING Modulating 9.2 -24 .0 kW
(31 ,400-82,000 Btu /h)
MAXIMUM DOMESTIC HOT WATER FLOW RATE FROM THE APPLIANCE Nominally 8.51itres /min (± 15%)
(1 .87 gallons/min)
EQUIVALENT DOMESTIC HOT WATER FL OW RATE
Nominally 9. 8litres /min
TO GIVE A TEMPERATURE RISE OF 35°C (2.16 gallons /min)
4

4. Siting The Appliance
4.1 The appliance must not be installed in any room contain-
ing a bath or shower or in a bedroom, bed-sitting room or
garage. Particularattention is drawn to the requirements of the
current I.E.E. Wiring Regulations and, in Scotland, the electrical
provisions of
the Building Regulations applicable in Scotland.
4.2
The appliance is not suitable for external installation.
4.3
The appliance does not require any special wall protection.
4.4
The wall must be capable of supporting the weight of the
appliance. See
Table 3.
4.5
If the appliance is to be fitted in a timber framed building,
refer to the British
Gas publication "Guide for Gas Installations in
Timber Framed Housi ng ".
4.6 The following clearances must be available for installation
and
for servicing. See Fig. 2.
Installation Servicing
Above 300mm 300mm
In front 600mm 600mm
Below*
900mm
230mm
Right hand side 100mm 100mm
Left hand side 100mm 100mm
4.7 No combustible surface must be within 75 mm of the cas·
ing . See BS476:4.
4.8 Always consider the possible need to disconnect the pipes
from the appliance after installation.
4.9 Boilers in roof
spaces or in understair locations require
special conditions.
Refer to BS 6798.
* 4. 10 The appliance must have a minimum clearance of900 mm
between the bottom
ofthe appliance and the floor.
Fig. 2. Appliance casing dimensions and required clearances.
106mm
SlOE VIEW
Space required above
for i nstallalion and servicing .
f----- -----------~
Space requ i red in front
fo r installat i on and servicing .
I
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:---- __ f _________ _j
////~/////J/~
I I
I I
I I
I :
I ~--~
I
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------~- - ~----
~225mm
FRONT VIEW
~-----4~mm----~
Fixing holes
~413mm CAS . ___,
I
I
II
900mm
~ I Space required below
/). 1 for installation and serv ici ng .
/)~ ____ ____ j t 1 I
Space required at left hand side -+1 I+- -+1 il
,,, ... , • •M .. ,...... . i L_ ______________ j! I
5
Space required at right hand side
for installa tion and servicing .

Fig. 3. Appliance pipework connections.
-· ·
-· "'
"": rr-;J
__ ,_::D
Centra l heating flow
55
mm Jj
Central hearing return i 08 mm
Ma i ns cold water in --114-- -- 161mm
Domest ic hot water out -1-- ---- 216 mm -----< ~
Pressure relief valve discharge -1-- ------- 306 mm -- ~
tt\·r:!\
-w·o
_,....,..YI.III_
Gas cock - 1-- ----------- 405mm ------ -~
5. Siting the Flue Terminal
The flue diameter is 125 mm Refer to BS 4543.
5.1
The flue must be installed as specified in BS 5440: Part 1.
5.2 A means of dis -connection of the flue should be provided
and positioned immediately above the appliance draught divert·
er .
5.3 Horizontal flue runs should be avoided and the flue should
terminate in accordance with the requirements of BS 5440 :1.
The terminal must be of a type approved by Br itish Gas and
must not be
within 600 mm (24 in) of an openable window. air
vent or other ventilation opening.
5.4 If the flue is to be taken through the wall behind the appli·
ance t hen adequate space must be available to allow the fitting
of a suitable flue bend. A right· angle bend is not acceptable. A
minimum of 600 mm of verti cal flue pipe is required before the
introduction
of a bend. If the flue is taken through the ceiling
and i nto the roof ·space or room above then a sleeve of non · com ·
bustible material allowing an air-space of at least 25 mm
between the flue and the sleeve must be provided. The flue pipe
must be held in the centre of the sleeve .
6. Air Supply
6.1 The room in which an appliance is installed must have a per ·
manent air vent to outside air or to a room which itse lf ha s
6
direct access to outside air. The minimum effect i ve area of t he
air vent(s) must be 104 cm
2.
6.2 There must be sufficient clearance around the appliance to
allow proper circulation of ventilation air. The clearances
required for Installat ion and Servicing will normally be adequate
for ventilation. See Section 4.6.
6.3 The minimum free areas required are g iven below .
Position of
Air from
Air direct
air vents the room
from outside
High Level 271 cm
2•
135 .5 cm
2.
(42 in
2.)
(21 .5 in2)
Low Level
542 cm
2•
271 cm
2•
( 84 in
2.)
(42 in
2.)
6.4 Refer to BS 6798 and BS 5440:2 for additional information.
6.5 A spillage test, as detailed in 855440:1, must be carried out
and any remedial acti on taken to ensure that the installation
meets the standard. The effect of any type of extract fan in the
premises must
be considered and an additional air inlet may be
needed from outside to counter the effect of the fan .

7. Sealed System
7.1 The system must comply with the requirements of BS 6798
and
BS 5449: 1.
7.2 The appliance must not be operated without the system
being
full of water, properly vented and pressurised.
7.3 The pressure relief valve operates
at 3 bar (45lb/in").The dis-
charge must be directed away from electrical components or
where it might be a hazard to the user.
7.4 The pressure gauge indicates the system pressure which
must be maintained.
7.5 The 10 litre expansion vessel is charged to 0.5 bar and is
suitable for a static head of 5 metres (17 . 5ft) . The pressure can
be increased
if the static head is greater than 5 metres (17 .Sft) .
7.6
With an initial system pressure of 0.5 bar, a system capacity
of about 104litres can be accommodated. Refer to BS 7074 Pt. 1
for more information. The charge pressure can be increased but
with a decrease
in system volume.
7.7
The filling point must be at low level. See Fig. 4.
Fig. 4 Sealed primary water system.
L ocl<shield valve . Radiator valve .
l 11111 111 J IIIIIllI
Note .A dtm c:oc:1t should be installed at
the lowest point of the heating cir cuit and
beneath the appliance .
Fig. 5. System filling and make-up.
Heating Return
Non return
valve
....
Worcester Combi-Fill System
Non return
va~ ~ Hose union l
1-----t..•- ... -t..•-"" : =: zr, ::u I 1 ~ ~
!l i~ Stop cock
II II
Test cock · : ~==•.] :
Temporary hose
7
7.8 Water loss must be r~placed . See Fig 6. The connection
should
be made in the central heating return as close to the
appliance as possible.
7.9 The make-up vessel,
if fitted, mus t be fitted with a non-
return valve.
7. 10 Repeated venting loses water from the system. it is essen·
tial that this water is replaced and the system pressure main-
tained.
7.11 Connections
to the mains water supply must not be made
without the authority of the local Water Company.
7.12 The pump is set at maximum and must not be adjusted.
7.13 Connections
in the system must resist a pressure of up to 3
bar.
7.14 Radiator valves must conform to BS 2767(10):1972.
7.1 5 Other valves used should conform to the requirements of
BS 1010.
7. 16 To make use of the extra heating available from the appli-
ance at the end of any demand, it is recommended that a single
small radiator be left permanently open.
Central heat i ng
Suled system
--expansion vessel
-· Water to Wa t er
heat excltlnger
by-pass ad j uster - ~+----l-+--+----J
Fill po i nt ----
Heamg return
Heating flow .
Heating Return
'
I
I
l
Nola . The mains cold i nlet
connection to the app li ance
must come before any other
connection from the cold supply .
Auto
air vent
.... ....,..__ FiiiPoint
' Heating Return
Domestic
cold water .
._ British Standard
stop valve .
Fi xed spindle type.
- Wa t er mai n.
JOOmm ( 12 inl min .
above the hi ghest
po i nt of the system .

8. Open Vent Primary Water System
See Fig . 7
8.1
The size of the flow and return pipework is given in Section
3 -
Thble 4. The components required to connect the appliance
to an open vent system are available as an optional extra
kit.
8.2 The feed and expansion cistern should be arranged so that
there
is a minimum static head of 0.3 metres (12in.) above the
top of the appliance
or above the highest point in the heating
circuit, whichever
is the higher. See F ig . 6.
8.3 The feed and vent pipe should be 22 mm diameter
and rise
continuously
from the appliance to the feed and expansion cis·
tern.
Fig. 6. Open ventwater system.
Feed and expansion tank
8.4 Apressure relief valve is not required on an open vented sys·
tern. If the pressure relief valve is left in position then a discharge
pipe must be fitted which terminates
in a position such that any
water or steam discharge does not cause a hazard to the occu·
pants or damage electrical components.
8.5 Air w
it hin the appliance will be expelled via the feed and
vent connection or dissipated into the rest of the system which
must be fitted with manual air vents
at any high point.
8.6 The pump is set to maximum and must not be reset.
8.7
To make use of the extra heating ava il able from the appli·
ance at the end of any demand, it is recommended that a single
small radiator be left permanently open.
- Overflow .
S.H .- Mnmum statiC hud 300 mm 11 2 111 .1
me85Uied from the top surface of the
appliance or t.ghest point in the heattng
system to the wat er level in the feed ill1d
expansiOn tank .
-r ·- ·- ·- · :-_-:_-==: -·- ·r
S .H .
j Primary feed ill1d vent S.H.
;~-;--;jj
1
-
1
jl r- -- - ----, pipel22mmlmustrise-
l " " I • I I I : I I : II : : I I contiooously .
I I I I I I I I I I ::I I I' I
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,tl . I'! I I I ~ .!., I I II I' I I . ...
\' - ---- ---~ ~---------'~
'T • I I
----- - - - t- - -- - - - _; - - - ~ - -- - -- - ~ --- - ...,
0 I
- - --L - _________ .:. __ - --- - ---,
lockstoeld v...,• . Radllltor valvt.
l tlll llll J llllllll
Nott .A dr0111 cock should be InStalled at
the lo west poont of the heat tng c1r cut ill1d
beneath the appliance .
9. Domestic Hot Water
9.1 The following are gener al requirements and, if necessary,
reference should be made to the local Water Company before
fit ·
ti ng the appliance.
9.2
MAINS COLD WATER INLET . Devices capable of preventing
the
flow of expansion water must not be fitted unless separate
arrangements have been made.
An expansion vessel connection
point
is provided within the appliance.
A 15mm connection is provided on the domestic
water inlet
elbow. A Zilmet Z160 is the preferred type. A thread
sealant
compatible with potable water must be used.
9.3
The final 600 mm ofthe mains cold water connection to the
appliance should be made
in copper tube only.
9.4
The appliance is suitable for a mains pressure of up to 10
bar (150 lb/ in ").
I
I
8
Central h ea un g
-· Water to Wate r
h eat ex changer
by - pass ad ju ste r- ~±--t+-1----'
,
F ill point -- ---'
Heating return
Heat ing f low .
'
Nota . The ma.ns cold 1 nle1
connection to the appfta nce
must come before any other
connection from the cold supp ly .
Domest ic
cold water .
._. B rinsn St andard
stop valve .
Fixed spindle type .
.... Waterma 111 .
9.5 The appliance is fitted with a mains supply isolating valve.
9.6
The maximum domestic hot water flow rate is 8.5
litres/min (±15
%) (1 .87 gallons/min).
9.7
In winter (when the mains inlet water temperature is lower)
a reduced
flow rate at the taps will be required to achieve the
maximum hot water delivery temperature available
in warmer
weather.
9.8
It is a requirement that long pipe runs to the taps or shower
should be insulated to prevent the rapid cooling of domestic hot
water after a tap or shower has been turned off. Refer to
BS5546:1990.
Pipe diameter: up
to 12mm. Max.length 20 metres.
Pipe diameter: up to 22mm . Max. length 12 metres.
9.9 Hot and cold taps
and mixing valves used with this appli·
ance must be suitable for operating at a pressure of up to 10 bar
(150 lb/in ').

9.10 No anti·syphonage arrangements are necessary except for
someloose head showers. See also Section 9.12 following.
9.11 Thermostatically controlled or pressure equalising shower
valves
will guard against the flow of water at too high a temper·
ature.
9.
12 The head of a loose head shower must not fall doser than
25mm
(1 in) above the top edge ofthe bath to prevent its immer·
sion in bath water. Alternatively the shower must be fitted with
an anti·syphonage device at the point of the
flexible hose con·
nections.
9.
13 The supply of hot and cold mains water direct to a bidet is
permitted, (subject to local Water Company requirements), pro-
vided that the bidet is of the over-rim flushing type. The outlet(s)
9
should be shroucded and unable to have any temporary hand
held spray attached.
No anti-syphonage arrangements are nee·
essary.
9.14 As the maximum temperature of the Water to Water heat
exchanger is limited by the control drcuit, there
is normally no
need for
water treatment to prevent scale accumulation. In
exceptional drcumstances a device to prevent scale formation
can be fitted.
Installation of a scale inhibitor assembly should be
in accor·
dance with the requirements of the local Water Company. An
isolating valve should be fitted to allow servidng. The water
hardness can be determined using a standard test paper or by
reference to the local Water Company.

1 0. Electrical
See Figs . 7, 8, 9, 10 and 11 .
1
0.1 MAINS SUPPlY 240 V - , 50 Hz, 150 watts.
External Fuse 3A Internal Fuses : T2A (F1) and T315mA (F2) .
10.2 It must be possible to completely isolate the appliance.
1
0.3 Connection to the mains supply should be via a double
pole isolator
with a contact separation of 3mm in all poles and
supplying the appliance and controls
only.
10.4 The appliance must be earthed.
10.5 Mains Cable. 0. 75 mm • (24 x 0. 20 mm) to BS 6500 Thble
16 .
If a new cable is needed it must be connected into the terminals
marked L
(Brown or Red lead), N (Blue or Black lead) and -t
(Green/'rellow or Green) and be held securely in the cable clamp.
Fig. 7. Wiring Diagram -Control panel and facia.
For access refer to Section 14 . NOTE : Ensure the earth lead is
longer than the live and neutral leads.
1
0.6 The wiring between the appliance and the electrical supply
shall comply with current lEE Wiring Regulations and any local
regulations which apply .
1
0.7 If a room and/ or frost thermostat is to be fitted refer to
Figs. 10 and 11 . The thermostats must be suitable for use on
mains voltage .
1
0.8 A facia mounted programmer is available as an extra.
Instructions
are supplied with the programmer kit.
10.9 Atime switch or programmer can be fitted externally to the
appliance.
10.10 SAFETY CHECK. After installation or in the event of an
electrical fault the electrical system shall be checked for short
circuits,
fuse failure , incorrect polarity of connections, earth
continuity and resistance
to earth.
(All components shown viewed from front of appliance.)
A
TO
CASVAI.Vl
IIAII AIIO
OOIIESTlC
HOT WATER
TltEAIIOST AT
COLOUR CODE
br - brown bl - blue gy - green and yellow bk-black or-orange
r-red w- wh i te y- yellow g- grey v- vi olet pk - pi nk
10
...,