Worcester 240 Combi OF free boiler manual

Worcester 240 Combi OF free boiler manual
SOH/Z
A ANORCESTER
BOSCH
240 Combi OF
WALL MOUNTED COMBINATION BOILER FOR CENTRAL HEATING AND
MAINS FED DOMESTIC HOT WATER
INSTALLATION AND
SERVICING INSTRUCTIONS
IMPORTANT:-[]
SUPPLEMENT
INCLUDED AT E
BACK OF BOOKLET
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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 APPLIANCE 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
1. Installation Requirements................c.ccocceoe.. lo... Page 2
2. General Information vice. Page 2
3. Technical Data ......................e PAGE A
4. Siting the Appliance ....................... 0. Page 5
5. Siting the Flue Terminal ................................... Page 6
6. AIrSupply oc PARE 6
7. Sealed System ... - сене Page 7
8. Open Vent Primary Water er system .. ee PAGE B
9. Domestic Hot Water .. ee... Page 8
10. Electrical... eines enn EEE Page 10
11. Installation … arteries KL Page 13
12. Commissioning ... ener ee Page 15
13, Instructions to the User .. SE PAGE 16
14. Inspection and Servicing. eee Page 17
15. Replacement of Parts Page 19
16. Short Parts List O DON PAGE 25
17. Operational Flow Diagram... OTI 31-940
18. Fault Finding eee PAGE 28
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 not be taken,in any way,as
overriding 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 (Installation and Use) Regulations 1984 as
amended, current IEE Wiring Regulations, local Building Regula:
tions, Building Standards (ScotlandyConsolidation) and byelaws of
the local Water Company, Health and Safety Document No. 635
(Electricity at Work Regulations). It should be in accordance with
the relevant recommendations of the following British Standards.
BS 6798:1987 Specification for installation of gas fired hot water
boilers of rated input not exceeding 60 kW.
BS 5449:1990 Central Heating for Domestic Premises.
BS 5546:1990 Installation of gas hot water supplies for domes-
tic purposes.
BS 5440:1:1990 Flues and Ventilation for gas appliances of rated
input not exceeding 60 kW: Flues.
BS 5440:2:1989 Flues and Ventilation for gas appliances of rated
input not exceeding 60kW: Air Supply.
BS 6891:1988 Installation of low pressure gas pipework installa-
tions up to 28 mm (R1).
1.4 To ensure that the installation will perform to the highest
standards, the system and components should conform to any
other relevant British 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 domestic hot water.
Fully modulating controls in the central heating and domestic
hot water modes of operation.
An expansion vessel, pressure gauge and pressure relief valve.
A by-pass for the central heating system.
Temperature safety cut-out controls.
A water flow regulator.
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 (F2).
2.6 GAS SUPPLY
The boiler requires 2.82 m'/h (96.8 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 any other appliances being
served. The table below gives an indication of limiting gas pipe
lengths and the allowance to be made for fittings. Refer to
BS6891 for further information.
The meter governor should deliver a dynamic pressure of 20
mbar (8in wg.) at the appliance.
The complete installation, including the gas meter, must be test-
ed for soundness and purged. Refer to BS 6891.
TOTAL LENGTH OF
GAS SUPPLY PIPE (metres) Pipe
Diameter
3 6 9 (mm)
Gas Discharge Rate (m3/h)
2.9 - - 15
87 58 4.6 22
18.0 120 94 28
Note:
Each fitting used in the gas line from the meter is equivalent to a
length of straight pipe which must 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 connection to a sealed system but
is suitable for use with an open vent system. The connections
are supplied as an optional kit.
The specified ventilation openings must not be obstructed.
Do not place anything on top of the appliance.
The clearances specified for servicing must be maintained.
2.8 FLUE
The flue must be generally vertical and have no horizontal runs,
The flue must end with a British Gas approved terminal.
2.9 CONTROLS
The electronic control system and gas valve modulate the heat
input in response to the central heating and domestic hot water
temperature settings between minimum and maximum,
The Operating Switch provides for the selection of domestic hot
Fig. 1. Appliance water flow diagram.
Automatic air vent Gas to Water
| heat exchanger
—й
Water flow > — ——
manifold
LE 4 а
Y Boiler
A
Sealed system
expansion vessel
Water to Water heat exchanger
--- Water diverter
A valve
Central heating y
by-pass adjuster | y
| - Y „а — —
Ral
| Pressure relief valve
Y — Domestic hot water out
——— Mans cold water in
— Centra! heating return
Central heating flow
Nu 7
water only (WATER) or central heating and domestic hot water
(HEATING & WATER} or OFF.
A facia mounted programmer is available as an optional extra. À
remote mounted programmer may be connected to the appli
ance.
The integral facia displays indicate the status of the appliance.
There is provision 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.
2.10 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 the appliance.
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.
A drain cock to BS 2879 must be fitted to the lowest point of the
system.
For circuit design purposes it is important that due note is taken
of the information given in Table 3 relating to the available
pump head.
2.11 SHOWERS, BIDETS, TAPS AND MIXING VALVES
Hot and cold taps and mixing valves used ir 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 high a temper-
ature.
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 mains 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 condition.
The appliance must not be operated with the boiler inner casing
cover removed.
Work must not be carried out on the appliance without the gas
and electricity supplies being 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 water 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 minimum 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 9.2 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 fixec. 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
Burner Settin Flue Diameter 125 mm
Output input Pressure $ Gas Rate
kw | Btu/h | KW | Btu/h | mbar | inwe | m?h | tt |
92 | 31400 | 126 | 43000 | 27 | 11 | 117 | 402 Flue Pipe BS 4543
16.1 54,900 | 21.2 | 72,300 7.3 29 2.03 696
240 | 82,000 | 30.1 | 102,700 | 15.0 6.0 2.82 56.8
TABLE 2
AVAILABLE PUMP HEAD
Boiler Output Head Min. Flow Rate | Temp. rise across
| | heating flow
kW Btu/h | metres | feet | litres/min | gal/min and return
92 | 31400 | 49 | 159 | 120 | 264 11°C (20°F)
16.1 54,900 | 2.54 8.25 23.0 5.07 11°C (20°F)
240 | 82000 | 20 | 65 230 | 5.07 15°C (28°F)
TABLE 3
SPECIFICATIONS
CENTRAL HEATING FLOW FITTING 22 mm Compression
CENTRAL HEATING RETURN FITTING 22 mm Compression
COLD WATER MAINS INLET FITTING 15 mm Compression
DOMESTIC HOT WATER QUTLET FITTING 15 mm Compression
GAS INLET FITTING Rel,
PRESSURE RELIEF VALVE DISCHARGE FITTING 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 (105 lb}
INSTALLATION WEIGHT 46 kg (101 Ib)
PACKAGED WEIGHT 49 kg (108 16)
TABLE 4
SPECIFICATIONS
PRIMARY WATER CAPACITY 2.7 litres (0.6 galls.)
MAXIMUM COLD SUPPLY PRESSURE
10 Bar (157 psi)
MINIMUM COLD SUPPLY PRESSURE (WORKING) FOR MAXIMUM HOT WATER FLOW
1.6 Bar (23.5 psi)
MINIMUM COLD SUPPLY PRESSURE (WORKING) 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 metres (1 ft)
QUTPUT TO DOMESTIC HOT WATER
Modulating 9.2-24.0 kW
(31,400-82,000 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 8.5 litres/min (+ 1 5 %)
(1.87 gallons/min)
TO GIVE A TEMPERATURE RISE OF 35°C
EQUIVALENT DOMESTIC HOT WATER FLOW RATE
Nominally 9.8 litres/min
(2.16 gallons/ min)
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. Particular attention is drawn to the requirements of the
current LE.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 Housing”.
4.6 The following clearances must be available for installation
and for servicing. See Fig. 2.
Installation Servicing
Above 300 mm 300 mm
In front 600 mm 600 mm
Below * 900 mm 230 mm
Right hand side 100 mm 100 mm
Left hand side 100 mm 100 mm
4.7 No combustible surface must be within 75 mm of the cas-
ing. See B5476:4.
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 of 900 mm
between the bottom of the appliance and the floor.
AAA ADA“
N
Space required above
Fig. 2. Appliance casing dimensions and required clearances. X
SLL Le LLL
|
| |
7 for installation and servicing. | —
77 TA 7 | | 1
106 mm | Mounting plate Î | | |
Y 7) | | E a |
|
7 | | ! |
‘ | |
Z = | | | La -225mm — |
|
7 | | |
7 | | |
/ | ‘ |
| 800 mm
| / | |
Mounting wall | SIDE VIEW Space required in fron | | FRONT VIEW
7 for installation and servicing. | |
- | | |
7 | |
Ne 360mm_ —— | | —— m — — 450 mm > |
7 | | |
| |
7 ) | Fixing holes |
7 | | [e 418 mm CRS — |
7 | || E
7 | | | \
————— _J .
J | |
77 A | + e E i
|
7 | Space required below | | || ||
7 | for installation and servicing. Space required at left hand side —m a — |
| | for installation and servicing. | | |
A — о — — — — — J Y | j !
Space required at right hand side
for installation and servicing.
7
@
ig. 3. Appliance pipework connections.
ETT
WATER DO
CFF CO
EATING & WATER aw
55 mm
Central heating flow ——t= -
Central heating return —t— 108 mm —
Mains cold water in — 161mm
Domestic hot water gut ——— — —— ——— — 216 MM — №
WW YET
Pressure rehef valve discharge 306 тт — — — =
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 British 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 then 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 vertical flue pipe is required before the
introduction of a bend. If the flue is taken through the ceiling
and into the roof-space or recom 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 а рег:
manent air vent to outside air or to a room which itself has
Bo =
LL | 38 mm All connections
\_ Gas cock 405 mm
direct access to outside air. The minimum effective area of the
air vent{s) must be 104 cm”.
6.2 There must be sufficient clearance around the appliance to
allow proper circulation of ventilation air. The clearances
required for Installation and Servicing will normally be adequate
for ventilation. See Section 4.6.
6.3 The minimum free areas required are given below.
Position of Air from Air direct
air vents the room from outside
High Level 271 cm”. 135.5 cm’,
(42 in?) (21.5 in’)
Low Level 542 cm”. 271 cm.
(84 in?) (42 in?)
6.4 Refer to BS 6798 and BS 5440:2 for additional information.
6.5 A spillage test, as detailed in BS5440:1, must be carried out
and any remedial action 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 (17.5ft).
7.6 With an initial system pressure of 0.5 bar, a system capacity
of about 104 litres 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.
7.8 Water loss must be replaced. 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, must 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
har.
7.14 Radiator valves must conform to BS 2767{10):1972.
7.15 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.
7
Fig. 4 Sealed primary water system.
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à X 3
пула | arar
Pa y pa {FE
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pit tue 1100 NEI
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ча — — — L = == сы кк === == == — — — д оо о = —
Lockshield valve. Radiator valve.
A
Automatic air vent — pal — Appliance casing.
НЕМ - Gas to Water
heat exchanger
Y Boiler
Г
—[ —H--Sened system Domestic
expansion vessel cold water.
Di --- Water to Water
{vérier valve heat exchanger
4
Central heating |
by-pass adjuster --[*!
~
e Pressure relief valve
11
1
1
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1
я
Fill point -———— beeen. Domestic hot water put
Heating return
4
Heating flow.
Ye British Standard
stop valve.
{
Nota. A drain cock should be installed at
beneath the appliance.
the lowest point of the heating circuit and
1
Note. The mains cold inlet
connection to the appliance
must come before any other
connection from the cold supply. o
' 4- Water main.
Fixed spindle type.
7
Fig. 5. System filling and make-up.
Heating Return Worcester Combi-Fili System
Non return Non return
valve valve Hose union ]
E i Stop cock
" pi
Test cock Mezza
Temporary hose
\
Make up
vessel
Auto
valve
y
Heating Return
Stop 300mm (12in} min.
coc above the highest
point of the system.
ранения Fill Point
Heating Return
8. Open Vent Primary Water System
See Fig. 7
8.1 The size of the flow and return pipework is given in Section
3 — Table 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 Fig. 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.
8.4 A pressure relief valve ís not required on an open vented sys-
tem. 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 within 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 available from the appli-
ance at the end of any demand, it is recommended that a single
small radiator be left permanently open.
/,
ig. 6. Open vent water system.
$.H. — Minimum static head 300 mm (12 in.)
measured from the top surface of the
apphance or highest point in the heating
system to the water level in the feed and
Lockshield valve. Radiator valve.
HILLS (HI
Feed and expansion tank —t—
Primary feed and vent
pipe (22 mm! must ise — e
continuously.
: SH
expansion tank. }
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SH. Connection [Re % for
combined feed and vent
и P
+ Appliance casing.
1
1
4 {-- Gas to Water
heat exchanger
1 Boiler
a
[+ Sealed system Domestic
“~~ expansion vessel cold water.
Y) Pump
Di | — + —-- Water to Water 1
iverter valve Tr heat exchanger
Central heating
by-pass adjuster - Fo
1 Pressure relief valve
|
|
|
|
y
Note. A drain cock should be installed at
the lowest point of the heating circuit and
beneath the appliance.
9. Domestic Hot Water
9.1 The following are general requirements and, if necessary,
reference should be made to the local Water Company before fit-
ting 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 of the 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 Ib/in”).
Fill point -———— ——— e Domestic hot water out
Heating return
$
Heating flow. | ag British Standard
stop valve.
I Fixed spindle type.
|
Nate. The mains cold inlet = Water mann.
connection to the appliance
must come before any other
connection from the cold supply.
”
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 1b/in).
9.10 No anti-syphonage arrangements are necessary except for
some loose 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 closer than
25mm (1in) above the top edge of the bath to prevent its immer-
sion in bath water. Altematively 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)
should be shrouded and unable to have any temporary hand
held spray attached. No anti-syphonage arrangements are nec-
essary.
9.14 As the maximum temperature of the Water to Water heat
exchanger is limited by the control circuit, there is normally no
need for water treatment to prevent scale accumulation. In
exceptional circumstances 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 servicing. The water
hardness can be determined using a standard test paper or by
reference to the local Water Company.
10. Electrical
See Figs. 7, 8, 9, 10 and 11.
10.1 MAINS SUPPLY. 240 V -, 50 Hz, 150 watts.
External Fuse 3A. Intemal Fuses: T2A (F1) and T315mA (F2).
10.2 It must be possible to completely isolate the appliance.
10.3 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 Table
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 +
(Green/ Yellow or Green) and be held securely in the cable clamp.
For access refer to Section 14. NOTE: Ensure the earth lead is
longer than the live and neutral leads.
10.6 The wiring between the appliance and the electrical supply
shall comply with current IEE Wiring Regulations and any local
regulations which apply.
10.7 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.
10.8 A facia mounted programmer is available as an extra.
Instructions are supplied with the programmer kit.
10.9 A time 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.
(Fig. 7. Wiring Diagram — Control panel and fa
cia.
(All components shown viewed from front of appliance.)
rT 77 E TTT TTT rr TTT 7
| Indicator Lights | Operating Switch |
|
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| | we || | = |
| HEATING & WATER т W | |
| STANDEY BEN ! | | |
ий | >
I
| ---- 1 т —— | | +
| Temperature Control |
ı Potentiometer |
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Control Facia
—
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bk |
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F2 FUSE
+ |
MAIN DRIVER BOARD | |
а |
FUSE | |
1
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23 12345 123 456 1234 5 §
FM IHREN |
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PUMP = &7 WATER CENTRAL DOMESTIC GAS VALVE
To OVERRUN 2 3 HEATING HOT WATER MOCUREG
GAS VALVE THERMOSTAT VALVE SENSOR SENSOR REGULATOR
MAIN AND Р e MICRO-SWITCH
HOT WATER
THERMOSTAT
COLOUR CODE
or—brown bi-blue gy—green and yellow bk—black or—orange
r—red w—white y—vyellow g—grey v—violet pk—pink
10
fo
(All components shown viewed from front of appliance.)
Fig. 8. Wiring Diagram — Components outside control panel.
— ——— — — — —_ — нь сан == ааа,
| COLOUR CODE
|- r—red w-—white y-—yellow g-grey v—violet pk—pink
re = О” | " *
a — L—
1
т
|
|
\
Central
Heating -—-—--"--
Sensor — — — -—— — e —— —
=
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A
| br—brown bl—blue gy—green and yellow bk—black or—orange
Pump
Overrun
Thermostat
No
br... Main Valve
fa +
£a у > Modureg
= у Regulator
|- - — — — — — — — — — —
|
Gas Valve
Domestic Hot
Water
Thermostat >
/
a Domestic Hot
(1) Water Sensor
nn
cl
lo POWER ON
INDICATOR
© DEMAND
INDICATOR
Fig. 10. Room thermostat
main driver board.
; - inal
connections. Ш + o e e Termina! X4 on
Remove link.
N
dowd
2
Honeywell room thermostat
T60608 (or similar.)
J
connections. Terminal X4 on
еее ? o main driver board.
Honeywell frost thermostat
1 3 T4160A {or similar.)
black black
L EU —
Г — TT == = ==
у | ® ХР 7: ® Хх РММ MAIN DRIVER BOARD |
| zen |
e FROST THERMOSTAT (IF FITTED) RELAY RY1 |
ME ser a part
T2A — —— „+ - — N e
| X4 PIN 4 X4 1PIN 5; TRANSFORMER LA |
X& PIN 31 E] |
| PO = > $ |
ROOM = = TEST e ELECTRONICS
| | THERMOSTAT | WATER DIVERTER VALVE pH
| X10 Xé MICRO SWITCH | FUSE F2 |
IPI% РЕМ 1: Xa ¡PIN 21 T315 mA
| en ger et Il grey |
H X3 yellow A
| e brown с PIN 73 X3 (PIN > @ X3IPIN à |
| X19 PIN 3: || DHW OPTIONAL LINK a |
- + D -
| white 10 ¡PIN 21 XI PIN 1 White | violet CH d
OPERATING SWITCH | ——e—{ ELECTRONICS
| (OR PROGRAMMER - e DHWÍ X3iPNSi |
| WATER DIVERTER VALVE | = |
MICRO SWITCH
| | | | _Mmchoswrceh | |
X5 PIN 31 ® CENTRAL HEATING SENSOR |
| X5 (PIN 1) DOMESTIC HOT WATER SENSOR |
| brown TEMPERATURE CONTROL POTENTIOMETER || |
| PUMP OVERRUN THERMOSTAT | VALVES N
| XE PIN 71 |
X6 (PIN 3!
Loa AMI |}
. A , — > №
\ Fig. 9. Functional flow diagram. PUMP — N
12345 f ri. 11. Frostthermostat 1 2345
11. Installation
11.1 The appliance is supplied suitable for fitting to a sealed
system. If it is to be fitted to an open vent system refer to Sec-
tion 11.2 following and Section 8.
The flue must be installed as specified in BS 5440 Part 1.
Note: READ THIS SECTION FULLY BEFORE COMMENCING
INSTALLATION
11.2 GENERAL FITTING.
Check that the appliance carton contains:- Appliance
Installers Instruction Pack Appliance Mounting Plate
Users Information Pack Installer Hardware Pack
Check that the position chosen for the appliance is in accor-
dance with the instructions given in Sections 4 and 5.
The distance from the bottom of the mounting plate to the top
of the appliance casing is 106 mm.
Hold the appliance mounting plate to the wall. Check that the
plate is horizontal. See Fig. 12.
Sealed System:
Unscrew and discard the automatic air vent cap. See Fig 13.
Open Vent System:
Remove and discard the automatic air vent. Fit the preformed
pipe {optional extra). Connect the feed and expansion tank. See
Fig 14.
Connect the flue pipe to the appliance and seal the gap between
the pipe and the spigot. The flue must be supported so that its
weight is not put upon the appliance. Connect and make good
the flue system and terminal as specified in BS 5440:1.
11.3 FINAL INSTALLATION
Check that all the water connections and the gas connection
have been tightened.
If a facia mounted programmer is to be fitted, unscrew the
upper two screws holding the facia panel in place and carefully
lower the facia. See Fig. 15.
Unplug the Operating Switch from the terminal X10 on the main
driver board. See Fig. 7. Unscrew the four screws holding the
switch plate and remove the complete Operating Switch assem-
bly. Fit the programmer and tighten the four screws. Plug the
7
Fig. 12. Appliance mounting plate and flue position.
F
| — линь ный = = = == == == == == В
a 0
o
a
о - 9
Mounting plate
flue opening centre line indicators
—— Apphance casing
TL
REAR FLUE POSITION
N
Mark the position of the fixing holes and the position of the flue
hole centre line anto the wall.
Drill the fixing holes 60 mm deep for No. 12 size plugs and fix
the appliance mounting plate, and check that it is horizontal
before tightening the screws.
The gas and water pipes can be led towards the appliance at
this stage. See Fig 3. It is recommended that temporary connec-
tions be made to thoroughly flush the central heating system.
Also flush the primary cold water supply pipe before the appli-
ance is fitted to the wall.
Prepare the opening in the wall or ceiling for the flue pipe. Hang
the appliance onto the wall. Drill (at a slight rising angle) through
the two appliance fixing holes at the bottom of the casing. Plug
and fix the casing bottom. Connect the gas, water and pressure
relief valve connections to the appliance. A 15 mm shut-off valve
(supplied with the installer Pack) must be fitted to the cold water
supply connection. See Fig 3.
Remove the cabinet front panel. Refer to Section 14.3 (a).
13
DIN
+
Mounting
wall
Meunting plate
1
Appliance casing -
265 mm nom. |
SIDE FLUE POSITION
programmer into terminal X10 on the main driver board.
Lower the control box as described in Section 14.3(d).
Connect the mains electrical supply to the appliance and con-
nect any room and/or frost thermostats. The electrical leads to
the room and frost thermostats must pass through the appropri-
ate holes in the control panel and be fixed with the cable clamps
provided. See Fig. 16. Refit the control box and facia panel.
Test the gas supply pipework up to the appliance for soundness
as indicated in BS 6891.
Refer to Section 12 for a full description of the filling, venting
and, with a sealed system, the pressurising of the system.
If the appliance is not to be commissioned immediately, replace
the cabinet front panel. Check that the gas supply, the electrical
supply and the water connections are all turned off.
If the premises are to be left unoccupied during frosty condi-
tions, then commission the appliance as described in Section 12
and leave it under the control of the frost thermostat or leave
operating continuously with the room thermostat set at 6°C.
If the unoccupation is to be of a long duration then drain the
appliance and system and commission the appliance upon re-
occupation.
/,
ig. 13. Automatic air vent.
Unscrew and discard the cap
Automatic air vent —
{Sealed systems anly)
HT
Feed and vent connection
(Open vent water system only)
|
|)
(Gas to Water heat exchanger
N
Boiler flow
Boiler return
J
F
~
ig. 14. Pipe connection for open vent
systems.
To feed and expansion tank
о
Pre-formed feed and vent pipe
To Gas to Water heat exchanger
14
/
Fig. 15. Appliance casing and control
equipment fixings.
/ \
| Y
Inner casing cover
fixing screws {2)
Cabinet side panel
fixing screws (2)
O
e] a
Control box fixing screws (2)
=
Upper facia panel fixing screws (2)
\_ Lower facia pane fixing screws (2}
~
(
Fig. 16. Electrical cable exits from control box.
GAS VALVE
MAIN AND
DOMESTIC
HOT WATER
THERMOSTAT .
=
SE
TO Earth MAINS w то
PUMP
E
§ MAIN DRIVER BOARD
весе) [о © + [6 5 = о =) XX « 00) [e vie wow 0e]
PUMP WATER CENTRAL DOMESTIC GAS VALVE
CVER-AUN DIVERTER HEATING HOT WATER MODUREG
THERMOSTAY VALVE SENSOR SENSOR REGULATOR
MICRO-SWITCH
TO ROOM THERMOSTAT __J L_ TO FROST THERMOSTAT
IOPTICMAL) OPTIONAL
12. Commissioning |
12.1 The appliance is despatched with the controls set to pro-
vide a maximum output for domestic hot water of 24 kW
(82,000 Btu/h) and satisfy a central heating load of 16.1 kw
(54,900 Btu/h). |
Domestic Hot Water System. Check that the mains water sup-
ply has been fully flushed out at installation.
Central Heating System. Check that the central heating system
has been fully flushed out at installation.
Gas Service . The complete system, including the meter, must be
inspected and tested for soundness and purged as indicated in
BS 6891.
12.2 APPLIANCE AND CENTRAL HEATING SYSTEM
PREPARATION
Remove the cabinet front panel.
Check that the electrical supply and the gas service to the appli-
ance are off. See Fig 3.
Check that all the water connections throughout the system are
tight. —
Open the system valves at the appliance. See Fig 3. Open all the
radiator valves, fill the system and vent each radiator in turn.
On sealed systems the automatic air vent, {fixed to the flow man-
ifold) will vent the appliance. Check that the air vent cap has
been removed. See Figs 13. |
Check that the pressure relief valve operates by turning the knob
anti-clockwise until it releases. Water should be expelled from
the discharge pipe. See Fig. 17. Lower the control box to gain
access. Refer to Section 14.3(d).
SEALED SYSTEMS ONLY
Set the Expansion Vessel Pressure
The charge pressure of the expansion vessel as despatched is 0.5
bar, which is equivalent to a static head of 5 metres (17 ft). The
charge pressure must not be less than the static head at the
point of connection. See Fig. 4. A Schraider type tyre valve is
fitted to the expansion vessel to allow the charge pressure to be
increased if necessary.
Set the System Pressure
Fill the system until the pressure gauge shows 2.5 bar (37
Ib/ins and check for water soundness. Release water from the
system using the relief valve test knob until the System Design
15
Pressure is obtained, up to a maximum of 1.5 bar.
System Design Pressure in bar = Static Head of the System in
bar + 0.3 |
Note: 1 bar is equivalent to 10.2 metres {33.5 ft) of water.
Set the movable pointer on the pressure gauge to coincide with
the indicating pointer giving a permanent record of the set
system pressure. |
If the pressure indicated on the pressure gauge is greater than
2.5 bar when operating at the maximum central heating tem-
perature, an extra expansion vessel must be fitted to the system
as close as possible to the appliance central heating return con-
nection.
The appliance (as despatched) can accommodate a system
volume of about 104 litres. Refer to BS 7074 Part 1. If the system
volume is in excess of that accommodated by the expansion
vessel fitted to the appliance then an extra vessel must be fitted
as close as possible to the central heating return connection of
the appliance.
Any extra vessel fitted must be pressurised to the same figure as
the integral vessel. If the expansion vessel fails then the speci-
fied replacement must be fitted.
12.3 PROGRAMMER
Any programmer fitted on the appliance should be set up at this
stage following the instructions sent with the programmer. The
(x в
ig. 17. Pressure relief valve.
r— Pressure gauge capillary connection
Test knob
Pressure relief valve discharge pipe
_/
plug-in programmer will retain the setting for up to four weeks
following an interruption in the electricity supply.
12.4 APPLIANCE OPERATION
Check that the gas supply to the appliance is off. Switch the elec-
tricity supply on at the mains. Put the Operating Switch to Heat-
ing and Water. Leave the system to operate in a cold state for
about 20 minutes, venting as necessary to remove air from the
system.
Set the Operating Switch to OFF Switch off the electrical supply
to the appliance. Turn on the gas supply. Check for gas sound-
ness around the gas valve.
Light the pilot by pressing in the grey button on the gas valve
and operating the red spark igniter button. When the pilot has
lit continue to hold the grey button in for a further 20 seconds
and then release it slowly.
If the pilot does not stay alight, twist the gas valve button anti-
clockwise. Wait for 3 minutes and repeat the operation until the
pilot has lit. Continue to hold the gas valve button for 30
seconds then release it slowly.
Test for gas soundness at the joint between the pilot pipe and
the burner with leak detection fluid.
Observe the pilot flame. It should be about 18-20 mm long and
envelope the thermocouple tip. If not, refer to Section 14.4. See
Fig. 23.
Loosen the burner pressure test point screw and connect a
pressure gauge. See Fig. 18.
Domestic Hot Water.
Set the Operating Switch (or Programmer) to WATER and fully
open a hat water tap.
The boiler should light at a burner pressure of 2-3 mb (0.8-1.2 in.
wg.) rising immediately to 14 and 14.5 mbar (5.6 and 5.8 in.
wg.). If the burner pressure is low, check that the supply pres-
sure at the gas valve inlet with the appliance operating is at
least 19 mbar (7.6 in. wg).
Note: The burner pressure is factory set and if (after checking
that the supply pressure is sufficient) the correct pressure is not
obtained then Worcester Heat Systems Service Department
should be contacted.
with the main burner alight test the integral gas supplies and
joints for soundness using leak detection fluid.
Gradually close the hot tap and check that the burner pressure
drops. Fuily open the tap and check that the burner pressure
rises. After 10 minutes operation check for spillage at the
diverter outlet as described in BS 5440:1. Fully close the tap and
check that the burner goes off. The pump will continue running
until the appliance has cooled to a preset temperature.
Set the Operating Switch (or Programmer) to OFF.
Central Heating
Check that all the radiator valves are open. Set the room thermo-
stat and the Central Heating Temperature Control to maximum.
On sealed systems check that the system is pressurised and set
to the required pressure as indicated on the gauge.
Set the Operating Switch (or Programmer) to HEATING &
WATER.
The burner will light.
The appliance will modulate its output from 9.2 kW (31,400
Btu/h) to the set output of 16.1 kW (54,900 Btu/h) over a peri-
od of about two minutes.
Check the system to ensure that all the radiators are heating up
evenly.
Shut down ail but one of the radiators and observe the burner
pressure fall. Open ail of the radiator valves and check that the
burner pressure rises.
If a greater heat output up to a maximum of 24 kW (82,000
Btu/h} is required, then the burner pressure must be adjusted at
the potentiometer located at the rear of the control box. Adjust
the potentiometer to give a burner pressure of 14.5 mbar. This
16
figure can only be achieved if the burner pressures are correctly
set in the domestic hot water mode.
Balance the system so that the required temperature difference
across the central heating flow and return pipes is obtained. See
Table 3.
Adjust the central heating by-pass valve until the same tempera-
ture difference is obtained. See Fig 19. This should be carried out
with only a single radiator operating. If thermostatic radiator
valves are fitted then one radiator should be left uncontrolled.
The bypass valve should never be fully closed.
Set the room thermostat to minimum and check that the burner
goes out. Reset the room thermostat to maximum and the burn-
er will relight and follow the normal operating procedure.
Set the Operating Switch {or Programmer) to OFF.
Turn off the gas service cock and the electrical supply to the
appliance. After about 60 seconds the flame failure device can
be heard to operate. Check for its correct operation by turning
the gas back on at the gas cock and attempting to light the pilot
without depressing the gas valve button. If the pilot can be lit in
this way, turn off the gas supply and contact Worcester Heat
Systems.
Disconnect the pressure gauge and re-tighten the test point
screw. Test for gas soundness at the screw,
Drain the system while the appliance is still hot.
Refill, vent and, with a sealed system, re-pressurise as described
in Section 12.2.
Domestic Hot Water and Central Heating
Light the pilot as described in the preceding notes.
Set the Operating Switch (or Programmer) to HEATING &
WATER. If a programmer is fitted, set the domestic hot water to
Continuous or 24Hrs and the central heating to ON. The burner
will light and heat will pass into the system. Turn on a hot water
tap and check that fully heated hot water is discharged from the
tap.
Close the tap and the burner will go off. The appliance will then
return to the central heating mode and automatically balance
with the system requirements.
Set the Operating Switch (or Programmer) to OFF and the burner
will go out.
12.5 COMPLETION OF COMMISSIONING
Disconnect the pressure gauge and tighten the test point screw.
Restart the appliance and check for gas soundness around the
test point screw.
Refit the cabinet front panel.
If the appliance is being passed over to the user immediately,
refer to Section 13 — Instructions to the User and set the controls
to the user's requirements.
If the appliance is to be left inoperative, check that the Operating
Switch is set to OFF. Turn off the gas service cock and switch off
the electricity supply.
If there is any possibility of the appliance and system being left
inoperative during frosty conditions, drain the appliance and
system. For short inoperative periods leave the boiler under the
control of a frost thermostat or operating continuously under
the control of a room thermostat set at 6°C.
13. Instructions To The User
13.1 Tell the user how to operate the appliance and hand over
the Users Instructions leaflet.
13.2 Tell the user what to do if the the heating system is not to
be used in frosty weather.
13.3 Tell the user the sealed system set pressure if applicable.
13.4 Tell the user of the importance of regular servicing. Worces-
ter Heat Systems Ltd offer a comprehensive maintenance con-
tract.
frio 18. Gas valve.
Electrical connections - Main valve
lprown + blus + greenzyeflowl
Eiectrical connectivns - Modureg regulatar
¡yellow + yellow!
Maximum pressure
Minimum pressure sdjuster— ADS
Note Turn the nuts clockwise E
"a neresse and anti-clockwise
io decrease the oressuyre
Maodureg cap
Modureg regulator head
\
fig 19. Central heating by-pass adjuster. N
Central heating fiow
N
13.5 Set the system controls to the user's requirements.
13.6 If an external programmer has been fitted which has a pro-
grammable domestic hot water facility then it is suggested that
this be set to Continuous or the equivalent.
14. Inspection and Servicing
14.1 To ensure continued efficient operation of the appli-
ance it must be checked and serviced as necessary at regular
intervals. The frequency of servicing will depend upon the
particular installation conditions and usage, but once per
year should generally be adequate. The extent of the service
required by the appliance is determined by the operating
condition of the appliance when tested by fully qualified
engineers.
Any service work must be carried out by competent engi-
neers such as British Gas or Corgi registered personnel.
14.2 PRE-SERVICE INSPECTION
Check that the flue terminal is clear.
Check that the ventilation and combustion air openings are
clear. See Section 6 — Air Supply.
Jo À
17
Pilot pipe connector
- ECO lead connection
Burner pressure test point
Inlet pressure test point
Ú
Ви,
Check the system and remake any joints or fittings which show
signs of leakage.
Refill, vent and, with a sealed system, re-pressurise as described
in Section 12. 2.
Operate the appliance and the system taking note of any faults.
Warning
Disconnect the electrical supply at the mains and turn off the
gas supply at the gas service cock on the appliance before
servicing. See Fig. 3
After completing the service always test for gas soundness as
indicated in BS 6891.
14.3 DISMANTLE THE APPLIANCE
To carry out a full and comprehensive service of the appliance
remove the following parts to gain access to the components
which need to be checked or serviced.
(a) Cabinet Panels. Remove the front panel by lifting off the
supports. Lower the control box as described in Section 14.3(d).
Pull off the lead from the spark generator. Unscrew the screw
fixing each of the cabinet side panels and remove the panels.
See Fig. 15.
(b) Inner Casing Cover. Remove the cabinet front panel. Un-
screw the two screws securing the cover to the casing and
remove. See Fig 15.
(c) Facia Panel. Check that the electricity supply to the appli-
ance is turned off. Remove the cabinet front panel. Unscrew the
two screws and lower the facia assembly. See Fig. 15.
(d) Control Box. Remove the cabinet front panel. Unscrew the
two screws as shown in Fig. 15. Support the assembly and allow
it to hinge down into the servicing position.
(e) Diverter. It is not necessary, nor possible to remove the
diverter assembly when servicing the appliance.
(i Combustion Chamber Cover. Remove the the inner casing
cover. Unscrew the four screws securing the cover and pull
downwards to remove the cover, See Fig 20.
(e) Main Burner Assembly. Remove the combustion chamber
cover. Unscrew the pilot fixing screws. Unscrew the two screws
and remove the burner assembly by lifting the front of the
burner and pulling forward. See Fig. 22.
(h) Flue Clean-Qut Cover. Unscrew the four screws and remove
the cover.
{i) Thermostat Cover. Unscrew the two screws and move the
cover to one side (electrical leads still attached). See Fig. 20.
14.4 SERVICE OF COMPONENTS
Clean the Main Burner. Brush the blade tops and mixing tube
with a soft non-metallic brush and check that all the flame ports
are clear. Inspect the injector and clean with a soft brush.
Replace the injector if it appears damaged. Do not use a wire
Fig. 20. Appliance components and fixings (upper assembly).
ie
>
\
/
/
/
/
va
/
7
4 Flue hood
VA / Thermostat cover
va & | Ин
/ . 3 y Pump overrun thermostat
7 De
7 7 Overheat thermostat
a O © a
a | "| Inner casing
4 Combustion chamber cover fixing screws (4) 7
/
7 Combustion chamber cover /
7 / Diverter paffle
И ~~
1 lo [m ol Y TT
7 /
/
| |
Thermostat cover
fixing screws (2)
Cleanout cover Cleanout
fixing screws (4) Cover
Access cover
7
О
Fig. 21. Pilot burner assembly.
m
Thermocouple
2m
a 3 Pilot injector
Spark electrode
O
18
brush or anything likely to cause damage.
The burner is fitted with a lint filter which can be removed by
unscrewing the nut at the end of the burner and removing the
endcap. Brush or wash in soapy water and carefully refit. Check
that the endcap is fitted correctly before tightening the nut.
Clean the Pilot Burner Assembly. Brush with a soft brush.
Remove the pilot injector and clean by rinsing it in warm water.
Replace the thermocouple if it appears damaged. Replace the
spark electrode if it appears damaged. Fit the electrode lead
before replacing the electrode.
Clean the Gas to Water Heat Exchanger. Cover the main burner
manifold with a cloth. Clean the heat exchanger using a soft
brush. Remove the deposits from the bottom of the combustion
Before removing any component holding water it is important
that as much water as possible is removed from the appliance.
(a) Appliance. Turn off the central heating flow and return
valves at the appliance. See Fig 3. Fit a tube to the drain tap on
the Water to Water heat exchanger and open the tap about one
turn. See Fig 26. Close the drain tap when the flow has stopped.
Extra water can be removed by operating the relief valve knob.
Some water will remain in the expansion vessel, pump,
diverter valve and Gas to Water heat exchanger and extra
care must be taken when removing these components.
{b) Domestic Hot Water Circuit. Turn off the mains cold supply
valve at the appliance using a flat-bladed screwdriver and open
the lowest hot water tap. See Fig 3. A quantity of water will
(Fig, 22. Main bumer fixings. >
TS
Main burner end cap
Main burner fixing screws (2)
\-
chamber. Do not distort any of the blades.
7
Combustion Chamber Insulation. Examine and replace any
pads that are damaged. See Section 15.7.
Controls. Remove any dust or deposits using a soft non-metallic
brush. Take care not to mishandle any component connections.
Reassemble the appliance in the reverse order.
Check that ALL components are in place and correctly fixed.
Leave the cabinet front panel to be fitted after checking the oper-
ation of the appliance.
14.5 TEST THE APPLIANCE
On completion of the service and reassembly of the appliance,
check for gas soundness and the correct operation of the appli-
ance as described in Section 12 — Commissioning.
Refit the cabinet front panel and reset the controls to the users
requirements.
15. Replacement of Parts
15.1 WARNING.
switch off the electricity and gas supplies before replacing any
components. After the replacement of any components, check
for gas soundness where relevant and carry out functional
checks as described in Section 12 — Commissioning
15.2 COMPONENT ACCESS
To replace components it is necessary to remove one or more
sections of the cabinet and cover plates within the appliance as
described in Section 14.3. The facia panel and control box may
also need to be lowered as described in Section 14.3
15.3 DRAINING THE APPLIANCE
Check that the electricity supply to the appliance is turned off.
19
x
Fig. 23. Pilot burner settings.
_/
remain in the Water to Water heat exchanger and the diverter
valve and extra care must be taken when removing these
components.
15.4 COMPONENT REPLACEMENT
1. Automatic Air Vent. (Sealed system installation only.) See Fig
13.
Remove the cabinet front panel and left-hand side panel as
described in Section 14.3(a).
Drain the appliance as described in Section 15.3(a).
Unscrew the assembly. Take care not to distort the pipework.
Fit the replacement assembly.
Open the valves and fill and re-pressurise the system as
described in Section 12.2.
2. Overheat Thermostat See Fig 20.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, the right-hand side panel and
the thermostat cover as described in Section 14.3(a) and (i).
Unscrew the two screws to release the thermostat head. Release
the thermostat connections at the gas valve. See Fig. 8.
Fit the replacement thermostat in reverse order ensuring that
some heat sink compound is on the mounting plate.
3. Gas to Water Heat Exchanger. See Figs 13, 24 and 25.
Check that the electricity supply to the appliance is turned off.
Remove the combustion chamber cover as described in Section
14.316.
Drain the appliance as described in Section 15.3(a).
Remove the screw securing the control box at the left-hand side
and lift off the left-hand side panel.
Remove the pump overrun thermostat, overheat thermostat,
and main burner as described in Sections 14.3(g), 15.4.6 and
15.4.2.
Remove the side panels of the combustion chamber by carefully
removing the insulation and removing the four screws. See Fig.
25.
Unscrew the flow pipe at the heat exchanger and at the bottom
left of the inner casing and remove the pipe.
Unscrew the return connection at the bottom left of the inner
casing and manoeuvre the heat exchanger from the casing.
Transfer the return pipe to the new heat exchanger.
Fit the replacement heat exchanger in the reverse order ensuring
all the fibre washers are in place and a layer of heat sink com-
pound is on each thermostat pad. Align the return pipe and
tighten the connection. Refit the combustion chamber side
plates and insulation pads.
Re-assemble the appliance in the reverse order.
Open the vaives and fill and re-pressurise the system as described
In Section 12.2.
4. Pump Overrun Thermostat. See Figs 8 and 20.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel, right-hand side panel and
thermostat cover as described in Section 14.3(a) and (i).
Unscrew and loosen the access cover on the baffle. See Fig. 20.
Use a long screwdriver, from above, to loosen the rear M4 screw
securing the thermostat to its mounting place on the Gas to
Water heat exchanger. Remove the front screw and thermostat.
Carefully remove the three wires from their connections and
make note of their positions.
Fit the leads to the new thermostat.
Fit the replacement thermostat ensuring a layer of heat sink
compound is between the faces.
5. Combustion Chamber Insulation. See Fig 25.
Check that the electricity supply to the appliance is turned off.
Remove the combustion chamber cover as described in Section
14.3(f). Remove the fibre insulation pads from the combustion
chamber side, rear, and front.
Fit the replacement pads in the reverse order taking care not to
damage them.
6. Main Burner. See Fig. 22.
Check that the electricity supply to the appliance is turned off.
Remove the burner assembly as described in Section 14.3(g).
Fit the replacement burner in the reverse order taking care not
to bend the pilot bracket on the main burner.
7. Thermocouple. See Figs. 21, 26.
Remove the inner casing cover as described in 14.3(b).
Unscrew the two screws and remove the pilot burner from the
main burner.
Unscrew the thermocouple at the pilot burner and the gas valve
and remove.
Fit the replacement thermocouple in the reverse order and refit
the pilot burner
8. Pilot Burner. See Figs. 21 and 23.
Remove the inner casing cover as described in 14.3(b).
Unscrew the two screws and remove the pilot burner from the
main burner Undo the pilot pipe. Unscrew and remove the ther-
mocouple.
Remove the spark electrode cable and pull out the electrode.
Fit the replacement burner in the reverse order ensuring that the
pilot injector is in place. Fit the electrode lead before replacing
the electrode. Check the pilot burner settings as shown in Fig.
23.
9. Main Burner Injector. See Fig. 22
Remove the main burner as described in Section 15.4.6.
Unscrew the brass injector at the back of the combustion cham-
ber
Fit the replacement injector in the reversé order.
10. Spark Electrode. See Figs. 21 and 23
Check that the electricity supply to the appliance is turned off.
20
Remove the pilot burner assembly as described in Sections
14.3(b) and 15.7.
Pull the spark electrode out of the clip.
Fit the replacement electrode in the reverse order, checking that
the spark gap is 4 to 5 mm. Fit the electrode lead before replac-
ing the electrode.
11. Pilot Burner Injector. See Fig 21
Remove the inner casing cover and pilot burner assembly as
described in Sections 14.3{b} and 15.4.8. Remove the injector (a
push fit inside the pilot assembly).
Fit the replacement injector in the reverse order.
12. Spark Electrode Lead. See Fig. 21
Check that the electricity supply to the appliance is turned off.
Remove the inner casing cover as described in Section 14.3(b).
Carefully pull the lead from the spark electrode and from the
spark generator.
Fit the replacement lead in the reverse order. Loosen the pilot
assembly to refit the lead to the electrode.
13. Piezo Spark Generator. See Fig. 26
Remove the cabinet front panel as described in Section 14.3(a).
Pull off the electrode lead. Unscrew the two screws and remove
the generator.
Fit the replacement generator in the reverse order.
14. Gas Valve. See Fig, 18.
Check that the electricity and gas supplies to the appliance are
turned off.
Hang the control box assembly in the servicing position as
described in Section 14.3(d).
Disconnect the pilot pipe. Unscrew and remove the black plastic
plugs. Carefully pull off the two yellow wires from their termi-
nals. Disconnect the thermocouple and the overheat thermostat
lead at the valve. Remove the eight screws securing the valve to
the pipework and remove the valve from the appliance.
Fit the replacement gas valve in the reverse order ensuring the
sealing washers are correctly fitted.
Turn on the gas supply and check for soundness.
To replace the Modureg head only.
Pull off the electrical connections. Unscrew the two screws
securing the Modureg head to the main body and remove.
Fit the new Modureg head (Honeywell 3061) in the reverse order
ensuring that the gasket is in the correct position.
To set the burner pressure. See Fig. 18.
The minimum and maximum burner pressures must be set after
a new gas control has been fitted.
Follow the procedure described in Section 12.4 - Appliance
Operation.
fr ÓN
ig. 24. Gas to Water heat exchanger
connections.
Boiler return
Boiler flow
| — ra
—
> 9
N Boiler flow connector screws
”
Fig. 25. Combustion chamber insulation.
= n
Gas to Water heat exchanger
je,
! "1
i 1
ТЫ .!
PA Combustion side panel an
! fixing screws (4}
| |
I |
i |
I
Side insulation pad Rear insulation pad Sige insulation pad
I
|
1
1
1
]
I
1
|
I
|
'
ЕЕ = = = = mal»
К.
Main burner
a
Fig. 26. Appliance components (lower assembly).
Pilot gas pipe
Thermocouple
Central
heating
sensor
Electrode lead
— Spark generator
® (red knoh)
Circulating pump
Gas valve
% ; Overheat
thermostat
leads
Expansion vessel |
Water |
diverter
valve
Water diverter
valve Water to water heat exchanger
micro-switch
assembly
Mains cold Drain cock
inlet filter
Gas inlet
Domestic hot water Domestic hot water flow Domestic hot
overheat thermostat restrictor housing water sensor
21
(Fig. 27. Circulating pump.
Flow connector
€ Central heating sensor pad
и
TIL 10) Top union connection
* И
10
Pump vent screw
Pump body
Pump motor fixing
screws 14}
@—
—
/
Lower union connection
Sleeve connector
еее”
JU Bottom pump connection
N 7
The maximum burner pressure must be set first, as any adjust-
ment of the maximum pressure influences the minimum pres-
sure setting.
Remove the the fixing screw and remove the the Modureg cover.
The Modureg cap must be replaced immediately the adjust-
ments have been made to ensure the proper operation of the
gas control.
Start the appliance in the domestic hot water mode as described
in Section 12.4 — Appliance Operation.
Adjust the maximum pressure adjustment nut to give a burner
pressure of 14.4 mbar. See Fig 18.
Switch off the appliance and turn off the electricity supply.
Remove a lead to the Modureg head.
—
Fig. 28. Expansion vessel and pump
assembly.
Boiler flow connection
> Г Expansion vessel connection
Central heating
sensor
Expansion vessel
connection
Expansion vessel
22
Switch on the electricity supply to the appliance and relight in
the domestic hot water mode. The burner pressure will remain
at the minimum setting.
Turn the minimum pressure adjustment screw until the burner
pressure is 2.9 mbar. See Fig.18.
switch off the appliance and turn off the electricity supply. Refit
the lead to the Modureg head.
15. Central Heating Sensor. See Fig. 26
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel as described in Section 14.3(a).
Carefully pull off the two leads from the sensor. Loosen the two
M3 screws securing the sensor to the fitting and remove the
sensor
Fit the replacement sensor with a layer of heat sink compound
between the faces. Refit the leads.
16. Domestic Hot Water Sensor. See Fig. 26
Check that the electricity supply to the appliance is turned off.
Hang the control box assembly in the servicing position as
described in Section 14.3(d).
Carefully pull off the two leads from the sensor. Loosen the two
M3 screws holding the sensor to the fitting and remove the
sensor.
Fit the replacement sensor in the reverse order ensuring a layer
of heat sink compound is between the faces. Refit the leads.
17. Circulating Pump. See Fig 27
Check that the electricity supply to the appliance is turned off.
Drain the appliance as described in Section 15.3(a).
Hang the control box assembly in the servicing position as
described in Section 14.3(d).
Undo the two union nuts and remove the pump from the pipe-
work. Support the pump and remove the electrical cover. Discon-
nect the electrical wires taking note of their positions.
Fit the replacement pump in the reverse order using new sealing
washers. Ease back the sleeved connector to allow the fitting of
the bottom washer.
Alternatively replace the pump head only by removing the four
Allen screws.
Open the valves and fill and re-pressurise the system as described
in Section 12.2.
Note. The direction of flow should be downwards. The speed
should always be set to maximum.
18. Expansion Vessel. See Fig 28
Drain the central heating circuit as described in Section 15.3(a).
Hang the control box assembly in the servicing position as
described in Section 14.3(d). |
Remove the gas valve as described in Section 15.14.
Undo the expansion vessel connection at the boiler flow connec-
tion and remove the vessel.
Fit the replacement vessel in the reverse order.
Open the valves and fill and re-pressurise the system as described
in Section 12.2. |
19. Pressure Relief Valve. See Fig 17
Drain the central heating circuit as described in Section 15.3(a).
Lower the control box assembly as described in Section 14.3(d)
Undo the discharge pipe connection and the pressure gauge
connection. Unscrew the valve taking care not to distort the
pipework.
Fit the replacement valve using a suitable thread sealing com-
pound. Reconnect the discharge pipe and pressure gauge.
Open the valves and fill and re-pressurise the system as described
in Section 12.2.
Fig. 29. Water diverter valve.
Boiler flow
Hot water to central
heating system.
el Hot water to
TT Water to Water
heat exchanger
Cold water to
Water to Water
heat exchanger
Cold inlet W—- Mains cold water in
friter housing
SN
Water diverter valve micro-switch assembly
7
Remove the micro switch assembly as described in Section
15.4.20.
Undo all the water connections to the valve and remove from
the appliance.
Fit the replacement valve in the reverse order ensuring that the
filter and all fibre washers are in place.
Open the valves and fill and re-pressurise the system as de-
scribed in Section 12.2.
22. Water to Water Heat Exchanger. See Figs. 3, 26, 29 & 30.
Check that the electricity supply to the appliance is turned off.
Drain the appliance and domestic hot water circuits as
described in Sections 15.3(a and b).
Loosen the mains cold water inlet connection and locknut at the
appliance. See Fig.3,
Hang the control box assembly in the servicing position as
described in Section 14.3(d).
Undo connection A and remove the coupling.
Undo connection B and move the pipe to one side. Undo con-
nections C, D and E. Loosen the two screws at the right hand fix-
ing bracket.
Protect the control box and carefully remove the heat ex-
changer as some water remains.
Transfer the boiler flow pipe (removed with the old heat ex-
changer) to the new heat exchanger using a new fibre washer.
7
Fig. 30. Water to Water heat exchanger connections.
~
Mains cold water In ——— =D 9)
20. Water Diverting Valve Micro Switch Assembly. See Fig 29.
Check that the electricity supply to the appliance is turned off,
Lower the control box assembly as described in Section 14.3(d).
Using a pair of fine nosed pliers, pull the circlip off and remove
the micro switch assembly from the valve. Lower the facia as
described in Section 14.3(c). Carefully pull off the Molex connec:
tion from terminal X3 on the driver board. Remove the strain
relief bush to withdraw the switch and lead assembly from the
appliance.
Fit the replacement micro switch assembly in the reverse order.
21. Water Diverting Valve. See Fig 29
Check that the electricity supply to the appliance is turned off.
Drain the appliance and domestic hot water circuits as
described in Sections 15.3(a and b). Hang the control box as-
sembly in the servicing position as described in Section 14.3.(d).
Flow restrictor assembly
23
Y 7
Water to Water heat exchanger
Drain paint
В,
Fit the replacement heat exchanger in the reverse order ensuring
all the fibre washers are in place.
Open the valves and fill and re-pressurise the system as described
in Section 12.2.
23. Domestic Hot Water Flow Restrictor. See Fig 26
Check that the electricity supply to the appliance is turned off.
Drain the domestic hot water circuit as described in Section
15.3(b).
Hang the control box assembly in the servicing position as
described in Section 14.3(d).
Undo the water connection A and remove the fitting. The plastic
flow restrictor is located within the brass housing on the heat
exchanger.
Fit the replacement flow restrictor and reassemble in the reverse
order ensuring the fibre washers are in place.
24. Pressure Gauge. See Fig 31
Check that the electricity supply to the appliance is turned off.
Drain the appliance as described in Section 15.3(a). Lower the
facia panel as described in Section 14.3(c).
Remove the two screws securing the gauge to the facia panel.
Hang the control box assembly in the servicing position as
described in Section 14.3(d).
Disconnect the capillary at the pressure relief valve and remove
the gauge.
Fit the replacement gauge in the reverse order ensuring the fibre
washer is in place.
Open the valves and fill and re-pressurise the system as described
in Section 12.2.
25. Operating Switch. See Fig 31
Check that the electricity supply to the appliance is turned off.
Lower the facia panel as described in Section 14.3(c).
Remove the leads from the rear of the switch making note of
their positions.
Squeeze together the two plastic retaining lugs to remove the
switch from the facia.
Snap in the replacement switch and reconnect the leads. Refer
to the wiring diagram, Fig. 7
26. Temperature Control Potentiometer. See Fig 31
Check that the electricity supply to the appliance is turned off.
Lower the facia as described in Section 14.3{c).
Pull the knob off the spindle. Unscrew the locknut and remove
the potentiometer from the facia panel. Remove the Molex plug
from terminal X1 on the driver board.
Fit the replacement potentiometer in the reverse order.
28. Domestic Hot Water Overheat Thermostat. See Fig. 26.
Check that the electricity supply to the appliance is turned off.
Hang the control box assembly in the servicing position as
described in Section 14.3(d).
Carefully pull off the two leads from the thermostat. Loosen the
two M3 screws holding the thermostat to the fitting and remove
the thermostat.
Fit the replacement thermostat in the reverse order ensuring a
layer of heat sink compound is between the faces. Refit the
leads.
27. Driver Board. See Fig 7
Check that the electricity supply to the appliance is turned off.
Lower the facia panel as described in Section 14.3(c)
Carefully pull off all the Molex connectors from the board. Dis-
connect the room and frost thermostat connections (if fitted)
from terminal X4. Remove the Operating Switch (or program-
mer) plug from terminal X10. Disconnect the mains supply
leads at terminal X7. Release the plastic catch in each corner of
the driver board and pull forward off the control panel.
Fit the replacement board in the reverse order ensuring it is
pushed firmly onto the four posts and clicks into place.
Refit the facia panel and hang the control kox assembly in the
servicing position as described in Section 14.3 (d).
Set the central heating operating pressure to 14.4 mb (5.8 in wg)
by adjusting (anti-clockwise to increase the pressure and clock-
wise to decrease the pressure) the central heating potentiometer
accessed through an opening in the rear of the control box. This
must be done with the boiler operating in the central heating
mode.
The adjustment is made using a thin flat-blacled screwdriver.
Fig. 31. Facia (rear view in lowered position).
\
| Е
Temperature control potentiometer
Operating Switch |
Indicator lights
MA
\
©]
©
и NS
Pressure gauge
_ 7
N
©
Operating Switch plate (or programmer) fixing screws (4)
Pressure gauge fixirg screws (2)
oT
24
16. Short Parts List
No GC No. Part Manufacturer's Reference No. WHS Part No.
41 378 581 | Gas Valve Honeywell-V4600N3061 1 ZAGAS181
114 | 378585 | Modureg Head (Gas Valve) Honeywell- V7335A3008 1 ZAGAS185
33 378 386 | Main Burner Aeromatic-AC 23/053578 1 ZAGAS164
47 378 387 |Lint Arrester Aeromatic 600049 1 ZF5PADBS
34 379 040 [Main Burner injector Stereomatic 4.4mm Dia. Type 7 1 ZAGAS163
35 379 673 |Pilot Burner Honeywell-Q385A 2010 1 ZBGASO92
36 382 850 |Pilot Burner Injector Honeywell-45.004, 108-001 38/36A 1 ZBGASO16
37 379 561 ¡Spark Electrode c/w lead Honeyweil-45900413—010 1 ZBGAS078
21 299 150 [Gas to Water Heat Exchanger Giannoni-PR 20/321 1 ZAGAS165
24 379 419 | Automatic Air Vent Intermes-02, 50, 010 1 ZMMISOS5
53 299 199 [Sensor and paste Elmwood-6655-9428-4 2 SPK0N39
94 299 202 | System Pressure Gauge (with Washer) Cewal 1 SPKOO40
74 386 789 | Pressure Relief Valve Caleffi-31 41, 3bar 1 ZCV1VO18
50 378 034 | Circulating Pump Grundfos-UPS 15-60, 120CL, NOCL 50526613 1 ZAMA[198
70 378 027 | Expansion Vessel {Sealed System} Inter Albion-MIS082/240 1 ZMMIS082
79 371 537 | Water to Water Heat Exchanger 1 SSA6161/1
37 379216 |Diverter Valve Giannoni-D2040 1 ZAGAS166
97 379 730 | Driver Board Honeywell W4115B, 1226 1 ZAGAS228
90 386 227 |CH Temperature Control Potentiometer Omeg-OW20BU 10KA 7 SSAHAROO2
93 386 778 |Operating Switch Arrow-200400E839AA 1 ZDELE237
10 299151 |Combustion Chamber Insulation (Complete) 1 SPK0033
122 | 371 539 | Programmer Kit (Optional) WHS Single Channel Grey 490 488 1 ZAMAJ164
42 371 540 [Gasket Pack — Gas 1 SPKOG22
61 371 541 | Gasket Pack - Water 1 SPK0023
60 379 215 |DHW Flow Restrictor Type E, White 8 litres/min. (+ 10%) 1 ZBUNC138
91 371 524 |Indicator Light - DEMAND Neon (Green) — complete with plug
IMO Ref. N19L R/S-Green 1 SSAHARDS1
92 371 525 |Indicator Light — POWER ON Neon (Amber) — complete with plug
iMO Ref. N19L R/S-Amber ! SSAHAROB2
22 299 277 | Pump Overrun Thermostat plus paste Thermodisc 60T13-500103 1 SPKOO88
59 378 416 | Filter MPMY 3326 Stainless Steel 1 ZBUNC229
115 299 032 |Fuse Pack 1 SPK0024
40 390 210 |Thermocouple Honeywell Q309A2747 1 ZBGAS035
48 393 652 | Spark Generator Vernitron 0207 1 ZBGASO10
19 299 152 |Overheat Thermostat Elmwood 2455RC, c/w lead 1 SSAHARO13
7 386 222 |Domestic Water Limit Thermostat plus paste Elmwood 2455R-9082 635 1 SPK0003
25
End of domestic hot 17. Operational Flow Diagrams
water Demand.
n Note. The alpha references in these charts are to be used for cross- referencing when fauit finding. See Section 18.
Operating Switch and Two minute pause. Operating Switch off. Room thermostat off.
room thermostat on. {Pump remains on. у ] 7
Y temperature, H Central heating
Escape pause | | temperature above set
Frost thermostat oa je red by central Main gas valve off. ” level. DEMAND indicator off.
on. Switch OFF-ON. eating sensor
ni |
EITHER EITHER
Y : — В Y G Y y =| Main gas valve off
ME Main Gas
Primary water Burner pressure Heat input modulated ‚
Central heating el valve Da temperature Burner pressure at increases from 2.2 mbar to maintain flow I Centra heating
Demand opens monitored by central — 2.2 mbar for two | to the setlevelovera PM] temperature set by етап
heating sensor. minutes. one minute period. temperature Control satisfied.
tenhometer.
Pump on, or continue
gi from pump overrun 1. Central Heating Mode. Frost thermostat off.
mode.
DEMAND indicator
illuminated.
Pump off, or continue
dpe if pump overrun is
requir ed.
—_ С
Repeatedly
Mains Depress press red After 20 seconds slowly
gas > 505 > igniter button og release gas valve button | we) Pilot flame | OUT
available valve until pilot (30 seconds flame has — | FLAME established
button flame is previously extinguished) | CONTINUES
observed
A Y FLAME EXTINGUISHED
Twist gas valve
button in the
tes? E
Wait for 3 minutes rection of
the arrow
46
Operating Switch ON
Wait for domestic hot | y
and tap on. ___| water temperature to «Г | Main gas valve Operating Switch OFF. Tap off.
fall below set level. off.
(Pump remains on).
N palo) DEMAND indicator off.
Pump on, or continue Domestic hot water Monitor primary water
from pump overrun temperature rises above via central heating
mode. pre-set level, sensor and continue
to centr) heating Main gas valve and
>| pila valve off.
EITHER
MAIN Domestic hot water Modulate heat input to
Hot water Signal à GAS temperature monitored maintain domestic hot _ Hot water Is there a central | NO
0 bean h > four such > VALVE — by domestic hot | water temperature at Demand heating Demand?
(Uvérrides centra eating + water , level. .
> mode and pump overrun ON Sensor y pres satisfied.
function | y Automatic start
up sequence
DEMAND ff
indi Pump off, tin
¡neo SEE DETAILED SEQUENCE ABOVE. | nte rover mode.
2. Domestic Hot Water Mode.
No Demand and Gas to ere heat
== a go ===
mperature causes
temperature above boller
thermostat to trip.
Pump on until primary Gas valve shuts
water temperature a down but pump
falls below 60°C. and indicator lights
remain on
{If Demand still exists)
3. Pump Overrun Function.
4. Overheat Protection.
This Fault Finding Chart is to be used in conjunction with the Operational
Flow Diagrams in Section 17. To find the fault, locate the point on the flow
diagram at which the appliance has failed, eg, letter B. Then read the
corresponding section in the fault finding chart, eg. Failure at point B.
Note: Each section assumes that the appliance operates correctly up to
that point.
Notes. 1. All voltage measurements are with respect to neutral unless otherwise stated. 2. Before changing any component indicated in the chart, it is
essential that the associated wiring is checked for continuity, condition and correct routing. 3. Preliminary electrical system checks are the first electrical
checks to be carried out during a fault finding procedure. On completion of the Service/Fault Finding task which has required the breaking and remaking
of electrical connections, check—(a), EARTH CONTINUITY, {b), SHORT CIRCUIT CHECK, {c), POLARITY and (d), RESISTANCE TO EARTH.
18. Fault Finding
NO NO
a Switch on the mains electrical Is there a 240V supply to terminal — pe===""1 Check the mains electrical supply
= supply. Is the STANDBY indicator X7 pin 1? and external wiring.
— illuminated?
= YES
—
=
= \ NO NO
> Is there a 240V supply at the top Fuse F1 has blown. Check all cables Check connections at the gas valve
un end of fuse F1? for damage or short circuits to Repair or replace as required.
ul chassis. Is cabling damaged?
= YES
ес YES
= Y Y
а Replace the STANDBY indicator | Repair fault and replace Fuse F1. |
a light.
=
a
oO
p=
he
=
Un
Start of pilot lighting test
pa
Set operator switch or programmer
(If fitted) to off Turn the room thermostat {If fitted) to NO Is there a gas NO Tum on gas supply
sequence to point A. Can a pilot flame be observed?
| YES
e
= Check that the pilot adjustment screw is NO Check condition of
o correctly set by screwing it in fully clockwise > Igniter leads and
a. and then unscrewing two revolutions. Does omer ons Does the ,
> the ingniter produce a spark? Igniter produce a spark’
= YES | YES NO
2 YES
= Replace igniter
< Is the pilot injector NO
= free from any blockage? |
| ve
Ensure gas has bled
through the system
nl
mud Has the Is the pilot
s the pi NO a
Follow the manual procedure to paint B Does the pilot NO overheat No > lame Check the pilot injector for
flame remain established? blockage. Replace if necessary
thermostat height 18 - and ensure the pilot
tripped? 20 mm? adjustment screw is
T ] correctly set by screwing
YES Y YES in fully and then unscrewing
Is the primary water temperature two revolutions
less than 95°C? NO
со Wait for the temperature to fall below
= | YES 95°C to reset the thermostat
O
e Disconnect the overheat thermostat and
о № Replace the
< check for contmuity across the device. |) "FL
i 7
= Does continuity occur? thermostat
2 y YES
< Check the soundness of the
ECO connections at the
thermocouple and gas valve NO
pears Replace the
(improve if necessary). T1 thermocourle
Follow procedure 5 in the ocoup
multimeter handbook. Does
the closed circuit voltage
exceed 8mV?
- Y y YES
END OF PILOT Replace the
LIGHTING TEST gas valve
28
START OF CENTRAL HEATING TEST
_ NO NO
Set the Operating Switch (or Is the STANDBY indicator still mun Refer to section STANDBY indicator
programmer) to HEATING & WATER illuminated? light does not illuminate.
and set the temperature control
potentiometer and room YES
thermostat (if fitted) to maximum.
Does the DEMAND indicator
illuminate?
YES
Y NO
= Is there a 240V supply at pins 1 and ==ia"1 Replace the Operating Switch (or
= 2 on terminal X10? programmer).
[=
= | YES
Lad
= | NO
= Is there a 240 supply at pin 2 on | Replace the room thermostat. |
= terminal X4.
y YES
NO
Is there à 240V supply at pin 3 on — Replace the flowswitch. |
terminal X3.
pre
| Replace the DEMAND indicator |
a
_ Y NO NO
| Does the pump run? > [5 there a 240Y supply at pin 20n — ¡me==a»1 Replace the pump overrun
= terminal X5? thermostat.
= YES
© YES
[=
< YES NO
= lf Remove the plated screw in the — Replace the pump.
= centre of the pump and turn the
a shaft with a flat bladed screwdriver
Does the pump now run?
Y — vo
Does the main No Does the pilot flame > Refer to failure at
burner Ignite? still exist? point A andB
YES
Y
NE Is there a 240v supply at | NO Is there approx 24V ac MO | arsformer 15 faulty
pin 1 on terminal X8 * | across the test pins on the ” | Replace the driver board
driver board?
y YES Ÿ YES
г Check connections to gas |
= remove the CH molex olu NO Check the connections at
= valve or replace gas valve mmo PO >| the central heating sensor
a from terminal X2.
= |5 the sensor resistance or replace the sensor
== between 1.5 and 25 konms
= across the white leads?
=
|
| YES
| Replace the driver board
E
29
NO NO
Ш Does the gas pressure remain at 2.2 ment Does the DC voltage across the gas — Replace the main driver board.
mbar for approximately two valve Modureg terminals remain at
La minutes and then increase to the a constant low voltage for
= set level over the next one minute? approximately two minutes and
= Note. The system load must be then gradually increase over the
= greater than 9kW and in a cool next one minute? Note. The voltage
Gl state for this to be possible. values are not important.
| «я
—
= YES e
| Replace the gas valve. |
Y NO NO
Does the gas pressure settle to pulls | Remove the Molex plug from mummies Replace the temperature control
maintain a constant flow terminal X1. Measure the resistance potentiometer on the facia panel.
temperature set by the temperature as follows: Between purple and
control potentiometer? (If the yellow pins - 10 kohms between
burner pressure is correctly purple and pink pins - between zero
balanced to the system load). and 10kohms depending on the
setting of the temperature control
= YES potentiometer. [s this correct?
= Ко
и NO
= Remove the left hand Molex plug —| Replace the central heating sensor
= from terminal X2. Is there a
= resistance of between 1.5and25 Log
kohms across the two white pins?
| YES
| Replace the main driver board.
> Y NO NO
я Gradually turn off the radiators one The overheat thermostat has
= y one Solna pti activated, Has the voltage across the
own as the sy
= rises above the set level Does the modureg terminals dropped below ell
N output drive at pin 1 on terminal 5vde? Wait for the temperature to la
= X8 drop from 240Y to OV during the below 95°C to reset the thermostat.
= shutdown? Relight the pilot
= YES
Y
| Replace the Modureg. |
—
=
= Y NO
5 [s there a 2 to 3 minute delay — Replace the main driver board. |
= before the appliance restarts?
=
= YES
[1
End of central heating test. Reset
the appliance and system controls.
=
=
©
(5
|
<<
ЗЕ
I=
=
—
и
|
FAILURE AT POINT K
—
fr
=
с
a
|
=
EL
[= 8
=
=
hi
START OF DOMESTIC HOT WATER TEST
NO
Is the STANDBY indicator still
illuminated?
YES
Refer to section STANDBY Indicator
light does not illuminate.
NO
[s there a 240Ÿ supply at pin 2 on
terminal X10?
a
Replace the Operating Switch (or
programmer;
y YES
NO
Is there a 240Y supply at pin 3 or
terminal X3?
hna д
Is the flow rate greater than
YES
| Replace the DEMAND indicator
|
NO
Is there a 240V supply at pin 2 on
terminal X5?
ee др»
| YES
Remove the plated screw in the
_ NO
Set the Operating Switch (or pr >=-
programmer) to WATER. Turn a
domestic hot water tap on fully
Does the DEMAND indicator
illuminate?
YES
Y NO
= | Does the pump run?
YES
YES
if
NO
| Does the main burner light?
centre of the pump and turn the
shaft with a flat bladed screwdriver.
Does the pump now run?
— Refer to failure at point E.
31
NO
— Replace the pump.
2.6 litres/min?
NO
| Investigate and rectify low flow rate. |
a
| Replace the flow switch.
Replace the pump overrun
thermostat.
Slowly reduce the domestic hot Does the DC voltage across the Remove the domestic hot water Replace the domestic hot water
water flow rate so that the gas Modureg terminals decrease as the Molex piug from terminal X2. Is sensor.
pressure reduces and settles. Does flow rate reduces? there a resistance of 1.5 to 25
the domestic hot water temperature À kohms across the red pins?
= stabilise at 55-60°C? YES
= YES
© YES
= NO
= Replace the Modureg. | Remove and inspect the domestic po Replace the main driver board. |
= hot water sensor. 1s it damaged?
ыы
y
Replace the domestic hot water
sensor
Y NO
Further reduce the domestic hot pee The overheat thermostat has
water flow rate so that the activated. Allow the overheat
appliance shuts down as the thermostat and repeat this test.
domestic hot water temperature
rises above the set level. Does the
burner re-ignite if the flow is
increased again?
YES
NO NO
FAILURE AT POINT N
E Turn off the tap. Does the burner jes Does the DEMAND indicator light — Replace the flow switch.
= shutdown immediately? go out immediately?
0.
=< YES | YES
Li
=
=
—
= | Replace the main driver board. |
End of domestic hot water test.
Reset the appliance controls.
START OF PUMP OVERRUN TEST
with no central heating or domestic sii | the STANDBY indicator light Refer to section STANDBY Indicator
hot water demand and with illuminated? does not illuminate.
а. primary water above 60°C
= (approx.}, does the pump operate? YES
=
= YES NO
я Is there à 240 supply at pin 3on j==")-1 Replace the pump overrun
= terminal X6. thermostat.
<=
|+ 95
|
| Replace the pump.
<
= Y NO
= When the primary temperature melo Replace the pump overrun
< drops below 60°C {approx}, does thermostat.
= the pump stop?
< YES
Y
| End of pump overrun test. |
OVERHEAT PROTECTION TEST
a at
|
= NO
o .
Does the burner shut down if the Replace the system overheat
<< Gasto-Water heat exchanger water thermostat.
= exceeds 100°C
>
=
=
|=
32
NOTE: PAGE Nos. GIVEN REFER TO MANUAL
ZKLIT504 ISSUE 2
PAGE 3:
2.12 SAFETY CONSIDERATIONS
The appliance must not be operated with the flue safety
thermostat put out of operation. Unauthorised interference with
this device can lead to serious consequences for the occupants
of the building in which this boiler is located.
PAGE 6:
6.6 FLUE SAFETY THERMOSTAT
À flue safety thermostat is fitted into the draught diverter to shut
off the main burner to limit the quantity of combustion products
that would be evacuated from the boiler in the event of a
blockage, or part blockage occurring in the flue system, or
excessive down-draught.
The flue safety thermostat should only be located on the
mounting bracket fitted for correct operation. Only replacements
from Worcester Bosch should be fitted to ensure correct
operation.
In the event of a shutdown by the flue safety thermostat it will
be possible to reset it within 30 seconds.
In the event of repeated shut down of the boiler by the flue
safety thermostat it will be necessary to take appropriate action
to remedy the discharge fault and it is necessary to carry out an
operational test after each intervention of the device.
PAGE 24:
28 FLUE SAFETY THERMOSTAT
Check that the electricity supply to the appliance is turned off.
Remove the right-hand side cabinet panel as described in Section
14.3(a).
Lower the facia panels described in Section 14.3(c).
Pull off the electrical connections, release the trip switch from
the top of the electrical control box by removing the retaining
nut. At the draught diverter, release the sensor from the plastic
retaining clips.
When fitting the replacement thermostat, carefully unwind the
side of the capillary sense line closest to the sensor so that the
spare coils remain close to the switch. When fitting the sensor,
ensure the sensor line is firmly engaged upon the plastic
retainers and the sense line does not come into contact with the
metal of the draught diverter and the sides or edges of the inner
metal cabinet.
Reassemble the appliance in the reverse order — EXCEPT -
reconnect the piezo spark lead to the piezo spark device before
refastening the right-hand side panel.
PAGE 10: WIRING DIAGRAM
( в
Fig. 7. Wiring Diagram — Control panel and facia.
(All components shown viewed from front of appliance
Pe E TU q
| indicator Lights |
| |
| nao (5) > WATER
| ba | OFF
| STANDBY E HEATING & WATER
bk.
| bi |
| 4 ——— —_—]—]—]———
Temperature Control |
' Potentiometer |
E — ее ее се ке не к ке — == ее —— | meee eer eer ee em em em a | не нение ее ое = те — — нано. ао O я и ны с ты т сн ны кей еее =
Control Facia
q
1 | bi a TT
x “| Shen * HL |
3 {| Nez FUSE i |
MAIN DRIVER BOARD | |
e Fi ! |
il bee : |
207 ' |
x1 ¥
X5 xa xa x2 3 в |
12 3 1 723 12345 123 458 1734 5 Mi |
099} 074 [8 © ‚9 #00 09] 1
- a Hee pally. a |
gy |bl br br or yyy Г МНЯ wi ww Y Y |
© Mu 5 CONO
a I
_ |
Ш
то то то то то -—
PUMP WATER CENTRAL DOMESTIC GAS WAIVE
CVERPUR DIVERTER HEATING HOT WATER MODUREO
THERMGSTAY $ 8 VALVE SENSON — SENSOR
2 p MCAO-SWITCH
COLOUR CODE
br—brown bl—blue gy—green and yeliow bk—black or—orange
r—red w—white y—yellow g—grey v—violet pk—pink
N J
PAGE 25: SHORT PARTS LIST
GC No. Part Manufacturer's Reference No. WHS Part No.
E00-770 Flue Safety Thermostat Ranco LM7-P5093 1 8 716 142 306
PAGE 12: FUNCTIONAL FLOW DIAGRAM.
ñ N
Fig. 9. Functional flow diagram.
> №
POWER ON © DEMAND
INDICATOR INDICATOR
Hack tack
KO | nn — — = TT 7
Ÿ | Qs: & X11 PN MAN DRIVER BOARD |
| PIN Hi
on — FROST THERMOSTAT (if FITTED) PEL IO a I
FUSE F1 N + PIN Y
” | T2A x N ra Xi PIN Bi TRANSFORMER os |
| | Jam X El ; |
| "ROOM 3 TEST $ ELECTRONICS .
i > |
ACH] Se” — Ten, ' |
a a
| ME amena Lg (ow | me qu | FLUE SPILLAGE
whale vi РН мт white | ‘ ‘ a CH SAFETY
| orev cues ХЛ } хам | Г мы = ELECTRONICS | | THERMOSTAT
| | WATER DIVERTER VALVE | | |
| — MICRO SWITCH i | | |
| KE PIN y $ CENTRAL HEATING SENSOR | \ MOT WAN
| DOMESTIC HOT WATER SENSOR | !
| TEMPERATURE CONTROL POTENTIOMETER | | A cas
| | маме; > №
| |
ee re ee
> №
> N
N
PAGE 24: FIG. 32. FLUE SENSOR FITTING. (Additional figure). PAGE 27: ADDITION TO OPERATIONAL FLOW DIAGRAMS.
4 в И
Operational Flow Diagram addition.
Sustained flue gas
B spillage causes safety
thermostat to trip.
Gas valve shuts down
but pilot remains
alight and
(if demand still exists)
pump and indicator
lights remain on.
5. Flue Spillage Protection
\.
PAGE 33: ADDITION TO FAULT FINDING.
/
Failure at Point S.
Does the burner
shutdown within 2 N
minutes if the flue is о
ий completely blocked
= when drawing DHW
= at max. rate?
«19
pu Replace the flue safety
<< thermostat.
= X
= Does the burner shut
= down if the flue No
< spillage sensor
; temperature exceeds
Ensure sensor and line do not come into contact 93°C?
with metalwork and hot surfaces.
N 7 PD
PAGE 29: REPLACEMENT TO FAULT FINDING “FAILURE AT POINT E.”
7
Failure at Point E.
Does the main No „| Does the pilot flame No оо Refer to Failure at
burner ignite? "о stil} exist? qe Point A and B.
Yes
Y
[5 there approx. 24V ;
sree | No | Cialis | No | Tammy
end inal X8? © | Pins on the driver Р board
on terminal X8? board? ard.
Yes
Y
Remove the C.H.
Yes Molex Plug rom No Check the connections
sensor resistance w | atthe central heating
between 1.5 and 25 sensor or replace the
kohms across the Sensor.
white leads?
Yes
Y
Replace the driver
board.
No Check there is 230Y at | No Check connections to
o the flue safety, ze both thermostat =| thermostat or replace
ermostat trippec: terminals? thermostat.
13]
= À
= Yes Yes
© Ÿ Ÿ
> 1. Ensure the thermo mi
< stat sensor and the Check for continuity No a. Replace DHW
= sense ine are roti thermostat terminals thermostat.
= hot surfaces or No
<< metalwork.
2. Inspect flue for Yes
blockages and clear. Y
3. Reset the trip.
4. Does the main Check connections to
burner ignite? gas valve or replace
gas valve,
Yes
Y
; No Has the flue safety No -
Does the main burner | TO ye | emermostat tripped oft |———— Check connections,
ght: again? replace gas valve.
Yes
Y
Re-set the trip switch
Yes and do spillage test to No - Refer to failure at
BS 5440-1. ло Point $.
Does spillage occur?
Yes
Y
Y Check flue is in
Do spillage test to accordance with the
BS 5440:1. manufacturer's
instructions.
a
A WORCESTER
Bosch Thermotechnik
Worcester Heat Systems Limited, Cotswold Way, Warndon, Worcester WR4 95W.
Telephone: (01905) 754624, Fax: (01905) 754619,
Technical Helpline (0990) 266241.
This booklet is accurate at the date of printing but will be superseded and should be disregarded if specifications and/or appearances are changed in the interests
of continued improvement.
All goods sold are subject to our official Conditions of Sale, a copy of which may be obtained on application.
PUBLICATION 8 716 145 052 — ISSUE 1 DECEMBER 1996
A WORCESTER
BOSCH
Worcester Heat Systems Limited, Cotswold Way, Warndon, Worcester WR4 95W.
Telephone: (01905) 754624 Fax: (01905) 754619
This booklet is accurate at the date of printing but will be superseded and should be disregarded if specifications and/or appearances are changed in the interests
of continued improvement.
All goods sold are subject to our official Conditions of Sale, a copy of which may be obtained on application.
PUBLICATION ZKLIT504 — ISSUE 2 NOVEMBER 1995
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