Worcester | 24I RSF | Specifications | Worcester 24I RSF Specifications

Worcester 24I RSF Specifications
24i RSF
WALL MOUNTED COMBINATION BOILER FOR CENTRAL HEATING
AND MAINS FED DOMESTIC HOT WATER
INSTALLATION AND
SERVICING INSTRUCTIONS
GC NUMBERS
N.G. 47 311 37 L.P.G. 47 311 38
BOILER OUTPUT
To Domestic Hot Water – Modulated Control
Minimum 7.5 kW (25,600 Btu/h)
Maximum 23.4 kW (80,000 Btu/h)
To Central Heating – Modulated Control\
Auto Range Rated
Minimum 7.5 kW (25,600 Btu/h)
Maximum 23.4 kW (80,000 Btu/h)
THESE INSTRUCTIONS APPLY IN THE UK ONLY
THESE INSTRUCTIONS ARE TO BE LEFT WITH THE USER OR AT THE GAS METER
This appliance must be installed by a competent person in accordance
with the Gas Safety (Installation and Use) Regulations 1998
Contents
1. Installation Requirements . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
2. General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
3. Data Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4
4. Siting the Appliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 5
5. Siting the Flue. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 6
6. Air Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 6
7. Sealed System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
8. Open Vent System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7
9. Hot Water Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 8
.........................................................
10. Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9
11. Installing the Appliance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 11
12. Commissioning the Appliance . . . . . . . . . . . . . . . . . . . . Page 16
13. Instructions to the User . . . . . . . . . . . . . . . . . . . . . . . . . . Page 18
14. Inspection and Service. . . . . . . . . . . . . . . . . . . . . . . . . . . Page 18
15. Replacement of Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 20
16. Conversion Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . Page 23
17. Operational Flow Diagrams. . . . . . . . . . . . . . . . . . . . . . . Page 24
18. Fault Finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 26
19. Component Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 34
1. Installation Regulations
2. General Information
1.1 Gas Safety (Installation and Use) Regulations, October 1994 all
gas appliances must be installed by a competent person in
accordance with the above regulations. Failure to install appliances
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,
confer immunity from legal obligations. In particular the
installation of this appliance must be in accordance with the
relevant requirements of the following;
Gas Safety (Installation and Use) Regulations 1998 as amended.
Current IEE Wiring Regulations BS 7671.
Local Building Regulations.
Building Standards (Scotland)(Consolidation).
Bylaws of the local Water Company.
Health and Safety Document No. 635 (Electricity at Work
Regulations).
The British Gas Material and Installation Specification for central
heating and hot water
It should be in accordance with the relevant recommendations of
the following British Standards.
BS6798:1987 Specification for installation of gas fired hot water
boilers of rated input not exceeding 60 kW.
BS5449:1990 Central Heating for Domestic Premises.
BS5546:1990 Installation of gas hot water supplies for domestic
purposes.
BS5440:1:2000 Flues and Ventilation for gas appliances of rated
input not exceeding 60 kW: Flues.
BS5440:2:2000 Flues and Ventilation for gas appliances of rated
input not exceeding 70kW: Air Supply.
BS6891:1988 Installation of low pressure gas pipework
installations up to 28mm (R1).
BS7593:1993 Central Heating system cleansing and flushing.
BS5482:PART 1 Domestic Butane and Propane gas burning
installations in permanent dwellings.
1.5 CARAVAN AND HOLIDAY HOMES
The installation must meet the following standards.
BS5482:2 LPG and EN721 ventilation.
1.6 PARK HOMES AND RESIDENTIAL
The installation must meet the following standards.
BS5482:1 LPG and BS3632 ventilation.
1.7 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.
1.8 The appliance complies with the Essential Requirements of the
Gas Appliance Directive and other Directives currently applicable.
1.9 This appliance contains no asbestos products.
There is no potential hazard due to the appliance being electrically
unsafe.
There are no substances used that are a potential hazard in
relation to the COSHH Regulations 1988.
1.10 The advice and instructions given in this document covers, as
far as possible, the foreseeable situations which may arise. Contact
Worcester Heat Systems Technical Helpline for advice on specific
installations.
The Benchmark initiative is the new code of practice to
encourage the correct installation, commissioning and servicing of
domestic central heating boilers and system equipment.
The 'Log-book' is a vital document that must be completed by
the installer at the time of installation. It confirms that the boiler
has been installed and commissioned according to the
manufacturers instructions.
Without the completion of the Log-book, manufacturers may refuse
to respond to a call-out from a householder, who will be advised
that he or she must call back the installer, who has not fulfilled his
obligations to record the information required by the initiative.
It is important that:
The services and the system are properly flushed as specified.
The User is clearly instructed on the correct operation of the appliance.
The benefits of regular servicing are explained - to maintain the
efficiency and extend the life of the appliance.
2.1 This appliance is not suitable for external installation.
2.2 The appliance controls are set to provide a maximum output of
23.4 kW for the domestic hot water and central heating load.
2.3 The control circuit provides direct burner ignition. A pilot is not used.
2.4 PRINCIPAL APPLIANCE COMPONENTS.
See Fig. 1.
Fig. 1. Water flow diagram.
Bi-thermal
gas to water
heat
exchanger
Automatic
air vent
Sealed
system
expansion
vessel
Domestic
water flow
switch
Circulating
pump
Pressure
relief valve
Fixed
by-pass
Safety
discharge
Domestic
hot water
out
Domestic C.H.
C.H.
cold
return
flow
supply
A low thermal capacity Gas to Water heat exchanger incorporating an
integral Hot Water heat exchanger to provide domestic hot water.
2
Fully modulating controls in the central heating and domestic hot
water modes of operation.
An expansion vessel, pressure gauge and pressure relief valve.
A fixed by-pass for the central heating system.
A Temperature safety cut-out control.
A water flow regulator.
A standard telescopic horizontal flue assembly giving flue lengths
from 330mm to 725mm.
Optional extra extension flue kits to provide for flue lengths up to 2500mm.
An optional vertical flue kit to provide for flue lengths up to
3400mm including vertical flue terminal.
Optional facia mounted mechanical programmer.
2.5 ELECTRICAL SUPPLY
Mains supply: 230V ~, 50 Hz, 180 watts.
External fuse: 3A., Internal fuses: 2AT HRC(F1), and 1 AF (F2).
Gas
Discharge
Rate
Gas Discharge
Rate
(m3/hr)
(m3/hr)
Total length of gas supply pipe
(metres)
3
6
9
12
Propane
1.5
–
–
–
8.0
5.2
4.2
3.6
15.9
8.8
8.5
7.2
Natural Gas
8.7
5.8
4.6
–
18.0
12.0
9.4
–
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.
2.11 SYSTEM NOTES
IMPORTANT
Check that no dirt is left in either the gas or water pipework as this
could cause damage to the appliance. The heating system should
be flushed and treated in accordance with the recommendations of
BS 7593:1992. Thoroughly flush cold water mains supply and
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 up to 3 bar.
Radiator valves must conform to the requirements of BS 2767:1991.
The relief valve discharge must be directed away from any electrical
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, section 3 relating to the available
pump head.
2.12 SHOWERS, BIDETS, TAPS AND MIXING VALVES
Hot and cold taps and mixing valves used in the system must be
suitable for operating at mains pressure.
Thermostatically controlled shower valves will guard against the
flow of water at too high a temperature.
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 simultaneously
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 to individual outlets.
2.13 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 unobstructed and the correct size.
IMPORTANT: Where back-flow prevention devices, including
water meters, are fitted the expansion of hot water into cold
water main can be prevented. This can result in a pressure
build-up that may cause damage to the boiler and household
devices such as showers, washing machines etc.
In these cases we recommend that a mini-expansion vessel be
fitted adjacent to the boiler in the cold water pipe.
2.14 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 of the delivered water. When
hot water is no longer required, the burner will extinguish. The fan
and pump may 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 a controlled
temperature rise. When the required heating temperature is
achieved 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 7.5 kW. If the system no longer requires
even the minimum output to maintain the desired room
temperature the burner will extinguish. The fan and pump may
continue to run to dissipate the residual heat from the appliance.
The appliance will remain off for a fixed period before re-lighting to
automatically meet the system requirements.
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 appliance will
return to the central heating state and its normal mode of
operation. The fan may continue to run to dissipate the residual
heat from the appliance as necessary.
2.15 DOMESTIC SUPPLY
Devices capable of preventing the flow of expansion water must not
be fitted unless separate arrangements have been made.
Pipe size
(Ømm)
15
22
28
22
28
2.6 GAS SUPPLY
The boiler requires 2.76 m3/h (97.5 ft3/hr) of natural gas with a
calorific value of 37.78 MJ/m3 (1014 Btu/ft3) or 1.07 m3/h (37.8
ft 3/hr) of propane with a calorific value of 95.65 MJ/m3 (2568
Btu/ft3). The meter governor should deliver a dynamic pressure of
20 mbar (8in w.g.) at the appliance, equivalent to a pressure of
about 19-19.5 mbar at the gas valve on natural gas or 37.0 mbar
(14.8in w.g.) at the appliance for propane.
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 complete installation, including the gas meter, must be tested
for soundness and purged. Refer to BS 6891.
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.
i.e.: Bend = 0.5 metres, Tee = 0.5 metres, 90° Bend = 0.3 metres.
2.7 PACKING
The appliance and flue components are packaged separately.
2.8 GENERAL INSTALLATION
The appliance is for connection to a sealed system only.
The specified ventilation openings made into a wall or
compartment door must not be obstructed.
If the appliance is to be fitted into a compartment then the compartment
must conform to the requirements of BS 6798: 1987: Section 7.
Do not place anything on top of the appliance.
The clearances specified for servicing must be maintained.
2.9 FLUE
The appliance has a multi-directional fanned flue system.
The standard telescopic flue assembly length is from 330mm to 725mm.
Extension flue kits are available for flue lengths up to 2500mm.
An optional vertical flue kit to provide for flue lengths up to
3400mm including vertical flue terminal.
A terminal guard, Type K2, GC 393 553, is available from Tower Flue
Components, Vale Rise, Tonbridge, TN9 1TB.
Do not allow the flue terminal fitted to the outside wall to become
obstructed or damaged.
A kit for internal fixing of the flue is available separately.
2.10 CONTROLS
The electronic control system and gas valve modulate the heat
input in response to the domestic hot water temperature and
central heating setting between minimum and maximum.
The Central Heating Temperature control knob provides for the
selection of domestic hot water only (Turned fully anti-clockwise) or
central heating and domestic hot water (Turned clockwise).
A facia mounted programmer is provided as an optional extra. A
remote mounted programmer may be connected to the appliance.
3
The data plate is fixed to the inner casing cover.
3. Data Tables
Table 1
kW
Btu/h
7.5
23.4
(25,600)
(80,000)
NOMINAL BOILER RATINGS
BURNER SETTING
INPUT (Net).
PRESSURE
kW
Btu/h
m bar.
in. wg.
NATURAL GAS
9.60
(32,750)
1.0
0.4
26.05
(88,890)
13.6
5.4
7.5
23.4
(25,600)
(80,000)
9.60
26.05
OUTPUT
GAS RATE
3
m /h
ft3/h
1.01
2.76
35.7
97.5
0.39
1.07
13.9
37.8
PROPANE
(32,750)
(88,890)
3.5
35.0
1.4
14.0
Table 2.
FLUE DETAILS
HORIZONTAL FLUE (Side or Rear)
FLUE DIAMETER
WALL HOLE DIAMETER
WALL HOLE DIAMETER (using internal flue fitting kit)
STANDARD FLUE – MINIMUM LENGTH
STANDARD FLUE – MAXIMUM LENGTH
EXTENDED FLUE – MAXIMUM LENGTH
mm
100
110
150
330/425*
725
2500
*NOTE: Flue lengths between 330 and 425 require the flue to be cut.
Table 3
AVAILABLE PUMP HEAD
BOILER OUTPUT
kW
7.5
23.4
Btu/h
(25,600)
(80,000)
HEAD
Metres
6.0
2.6
MIN. FLOW RATE
Feet
19.7
8.5
L/min.
9.8
30.5
Gal/Min.
2.2
6.7
TEMPERATURE RISE
ACROSS HEATING
FLOW AND RETURN
11°C (20°F)
Table 4
SPECIFICATIONS
CENTRAL HEATING FLOW FITTING
CENTRAL HEATING RETURN FITTING
COLD WATER MAINS INLET FITTING
DOMESTIC HOT WATER OUTLET FITTING
GAS INLET FITTING
PRESSURE RELIEF VALVE DISCHARGE FITTING
OVERALL HEIGHT (including flue turret)
CASING HEIGHT
CASING WIDTH
CASING DEPTH
WEIGHT(including water)
INSTALLATION WEIGHT
PACKAGED WEIGHT
PRIMARY WATER CAPACITY
MAXIMUM COLD SUPPLY PRESSURE
MINIMUM COLD SUPPLY PRESSURE (working) for max. hot water flow
MINIMUM COLD SUPPLY PRESSURE (working) to operate appliance
MAXIMUM CENTRAL HEATING FLOW TEMPERATURE
OUTPUT TO DOMESTIC HOT WATER
OUTPUT TO CENTRAL HEATING
MAXIMUM DOMESTIC HOT WATER FLOW RATE (from the appliance)
EQUIVALENT DOMESTIC HOT WATER FLOW RATE TO GIVE A TEMP RISE
OF 30°C (SPECIFIC RATE)
SEDBUK
4
22mm Compression
22mm Compression
15mm Compression
15mm Compression
Rc 1⁄2inch
15 mm Copper Tube
960mm (37.8 inches)
800mm (31.5 inches)
450mm (17.7 inches)
360mm (14.2 inches)
44 kg
39 kg
44 kg
3.0 litres
10 Bar (150 psi)
0.9 bar
0.1 bar
Nominally 82°C (180°F)
Modulating 7.5 to 23.4 kW
Modulating 7.5 to 23.4 kW
Nominally 8.0 ± 15% litres/min
Nominally 11.2 litres/min
78.3% D
4. Siting The Appliance
Fig. 2. Appliance casing dimensions and
required clearances.
Above turret
30mm
In front to a fixed surface
600mm
Below
200mm
Right-hand side
10 mm
Left-hand side
10 mm
30mm*
200mm
222
mm
225mm
Side view
360mm
Front view
600mm*
200mm*
450mm
10mm*
10mm*
* Space required for installation and servicing
Notwithstanding the instructions given in BS 5440:2, this appliance
may be fitted in a compartment with no vents as long as the
minimum clearances stated in Section 6: Air Supply, are maintained.
4.7 The airing space must be separated from the boiler space by
a perforated non-combustible partition. Expanded metal or rigid
wire mesh are acceptable provided that the major dimension is
less than 13mm. See BS 6798:1987.
4.8 No combustible surface must be within 75mm of the casing.
See BS476:4.
4.9 Always consider the possible need to disconnect the pipes
from the appliance after installation.
4.10 LPG Installation: The appliance shall not be installed in a
room or internal space below ground level when it is
intended for use with LPG. This does not preclude the
installation into rooms which are basements with respect to
one side of the building but open to ground level on the
opposite side.
5
800mm
4.1 The appliance may be installed in any room although
particular attention is drawn to the requirements of the current
IEE Wiring Regulations BS 7671 and, in Scotland, the electrical
provisions of the Building Regulations applicable in Scotland,
with respect to the installation of appliances in rooms containing
baths or showers.
Where a room sealed appliance is installed in a room containing
a bath or shower, any electrical switch or appliance control using
mains electricity must not be able to be touched by a person
using the bath or shower.
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 4.
4.5 The following clearances must be available for installation
and for servicing. See Fig. 2. (note the clearances at the front are
for a removable panel e.g. a door).
4.6 The appliance can be installed in a cupboard used for airing
clothes provided that the requirements of BS 6798 and BS
5440:2 are strictly followed.
5. Siting The Flue
6. Air Supply
See Fig. 3.
5.1 The flue must be installed as specified in BS 5440:Part 1.
5.2 The terminal must not cause an obstruction nor the
discharge cause a nuisance.
5.3 If a terminal is fitted less than 2 metres above a surface to
which people have access then a guard must be fitted. See
Section 2.9.
5.4 The terminal guard must be evenly spaced about the flue
terminal and fixed to the wall using plated screws.
5.5 In certain weather conditions a terminal may steam and
siting where this could cause a nuisance should be avoided.
5.6 Take care to ensure that combustion products do not enter
ventilated roof voids.
6.1 The appliance does not require a separate vent for
combustion air.
6.2 The appliance can be fitted in a cupboard with no vents for
cooling but the minimum clearances must be increased to those
given below (note the clearances at the front are for a removable
panel e.g. a door).
Above the Turret
30mm
In front
250mm
Below
200mm
Right-hand side
75mm
Left-hand side
75mm
6.3 If the appliance is to be fitted in a cupboard or compartments
with less clearance than those above (minimum clearances given
in Section 4. Siting The Appliance) then permanent vents for
cooling are required. One at high level and one at low level, either
direct to outside air or to a room. Both vents must pass to the
same room or be on the same wall to the outside air.
6.4 The minimum free areas required are given below.
6.5 Refer to BS 6798 and BS 5440:2 for additional information.
POSITION OF
AIR VENTS
AIR FROM
THE ROOM
HIGH LEVEL
270cm
LOW LEVEL
270cm
AIR DIRECT
FROM OUTSIDE
2
2
135cm
2
2
135cm
Fig. 3. Siting of the flue terminal.
A
L
G
B,C
K
L
D
K
F
F
HI
A
F
J
TERMINAL POSITION
A– directly below an openable window or
other opening e.g. air brick.
B– Below gutters, soil pipes or drain pipes.
C– Below eaves.
D– Below balconies or car port roof.
E– From vertical drain pipes and soil pipes.
F– From internal or external corners.
G– Above ground, roof or balcony level.
H– From a surface facing a terminal.
E
G
M
MIN. DISTANCE
TERMINAL POSITION
I– From a terminal facing a terminal
J– From an opening in a car port (e.g. door
window) into dwelling.
K– Vertically from a terminal on the same
wall.
L– Horizontally from a terminal on the same
wall.
M– From door, window or air vent.
300mm
75mm
25mm
25mm
25mm
25mm
300mm
600mm
MIN. DISTANCE
1200mm
1200mm
1500mm
300mm
300mm
6
7.7 The filling point must be at low level. See Fig. 4.
7.8 Water loss must be replaced. See Fig 4. The connection
should be made in the central heating return as close to the
appliance as possible. A filling loop kit is supplied.
7.9 Repeated venting loses water from the system. It is essential
that this water is replaced and the system pressure maintained.
7.10 Connections to the mains water supply must not be made
without the authority of the local Water Company.
7.11 The pump is set at maximum and must not be adjusted.
7.12 Connections in the system must sustain a pressure of up to
3 bar.
7.13 Radiator valves must conform to BS 2767:10.
7.14 Other valves used should conform to the requirements of
BS 1010.
7.15 The appliance is fitted with a fixed internal by-pass. But it is
advisable to keeps one radiator permanently open.
7. Sealed System
See Figs. 4.
7.1 The system must comply with the requirements of BS 6798
and BS 5449.
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/in2). The
discharge 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 8 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 up to 100 litres can be accommodated. For system capacities
greater than this an extra expansion vessel must be fitted. Refer
to BS 7074 Pt. 1 for more information. The charge pressure can
be increased but with a consequent decrease in system volume.
8. Open Vent System
The appliance is NOT suitable for connection to an open vented
system.
Fig. 4. Sealed primary water system.
Automatic
air vent
Expansion
vessel
Mains cold
water
Radiator
valve
Hot water
out
Lockshield
valve
Heating
return
Heating
flow
British Standard
stop valve.
Fixed spindle type
Water main
NOTE: A drain cock should be installed at
the lowest point of the heating circuit and
beneath the appliance.
7
9.10 No anti-syphonage arrangements are necessary except for
some loose head showers. See also Section 9.11 following.
9.11 Thermostatically controlled or pressure equalising shower
valves will guard against the flow of water at too high a
temperature.
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
immersion in bath water. Alternatively the shower must be fitted
with an anti-syphonage device at the point of the flexible hose
connections.
9.13 The supply of hot and cold mains water direct to a bidet is
permitted, (subject to local Water Company requirements),
provided 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
necessary.
9.14 LIME SCALE. In temporary hard water areas (more than
350mg/litre or 200ppm calcium bicarbonate) it is
recommended that a proprietary scale reducer is fitted in the
mains cold water connection to the appliance. Consult the
local water company for additional advice.
Installation of a scale inhibitor assembly should be in
accordance with the requirements of the local Water
Company. An isolating valve should be fitted to allow
servicing. The water hardness can be determined by
reference to the local Water Company.
9.15 NOTE: HOT WATER ONLY.
If required the appliance may be used for Hot Water only
before the Central Heating is connected. A 22mm copper bypass pipe at least 4 metres long must be connected between
the Central Heating Flow and Return, but it is advisable to
connect a small radiator instead.
IT IS NOT RECOMMENDED TO USE THE BOILER IN THIS
CONDITION FOR EXTENDED PERIODS.
9. Hot Water Supply
9.1 The following are general requirements and, if necessary,
reference should be made to the local Water Company before
fitting 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.
A mini expansion vessel kit is available which contains the
necessary parts for fitting an internal expansion vessel to the
appliance.
See Section 19 COMPONENT PARTS LIST.
A thread sealant compatible with potable water must be
used. An external expansion vessel may be fitted on the
mains cold water connection to the appliance.
9.3 The final 600mm 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 lb/in2).
9.5 The appliance is fitted with a mains supply isolating valve.
9.6 The maximum domestic hot water flow rate is 9.4 litres/min
(±15%) (1.8 gallons/min).
9.7 In winter (when the mains inlet water temperature is lower) a
reduced flow rate at the taps may be required to achieve the
type of hot water delivery temperature available in warmer
weather.
9.8 It is suggested 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.
9.9 Hot and cold taps and mixing valves used with this
appliance must be suitable for operating at mains pressure and
temperatures of 65°C.
Fig. 6. 230V programmer connections.
Fig. 5. 230V room thermostat connections.
RN
RI
CN
RL
CI
CL
X2
Motor
8
Live
Switched live
Neutral
Live
Neutral
Remove link
Switched live
X2
Remove link
be used in conjunction with a programmer.
Important: To provide external frost protection the appliance
must have the Central Heating Temperature Control Knob set to
supply heating (the appliance may then be left with the central
heating turned off on the programmer).
Connection must be made at X2 terminals RI and CL. For advice
on external frost thermostats contact Worcester Heat Systems
Technical Helpline
10.11 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.
10. Electrical
10.1 MAINS SUPPLY.
230 V ~, 50 Hz, 180 watts.
External Fuse: 3A. Internal Fuses: 2AT HRC(F1), and 1.AF (F2).
10.2 It must be possible to completely isolate the appliance.
10.3 The following connection alternatives must be used:
A 3 amp fused three-pin plug and unswitched shuttered socket
outlet (both complying with the requirements of BS 1363) or 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. 0.75mm2 (24 x 0.20mm) to BS 6500 Table 16.
The mains cable must be connected into the terminal X1,
marked L (Brown or Red lead), N (Blue or Black lead) and the
earth stud and be held securely in the cable clamp. For access
undo the three bottom screws and remove the facia access cover.
See Fig. 7.
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 thermostat and/or external programmer is to be
fitted refer to Figs 5 and 6. The devices must be suitable for use
with mains voltage.
10.8 A facia mounted mechanical programmer is available as an
optional extra. Instructions are supplied with the programmer kits.
10.9 A time switch or programmer can be fitted externally to the
appliance.
10.10 The boiler provides automatic frost protection, so the use
of a frost thermostat is not recommended. However if an
external frost thermostat is considered necessary then it must
Fig. 7. Mains electricity connections.
230V
N
L
X1
X2
Green/y
ellow
ue
Bl
Brown
Blue
Brown
Strain relief clamp
Green/yellow
Programmer and room thermostat
strain relief clamps
Fig. 8. Wiring diagram.
Fig. 8. Wiring diagram.
Flame sense
electrode
Spark
electrode
Spark
transformer
Flow
switch
X3
X6
2 Yellow
2 Blue
Mains in
2 Orange
2 pink
2 Red
Link
Blue
Brown
Link
Blue
Brown
X2
Brown
Blue
X1
X4
Blue
Brown
X5
DHW
sensor
Air
pressure
switch
Brown
White
Green
BLACK 'EAC' OR WHITE 'HUBA'
Fan
Gas
valve
Main
Reg
3 COM
2
Pump
CH
sensor
1 NC
2 NO
3
1
Safety
limit
stat
9
Air pressure
switch
(White 'HUBA')
CH control POT
DHW temp. sensor
CH temp. sensor
X6 Pins 3 & 4
Flow signal
Outputs
X6 Pins 19 & 20
Air pressure switch
X6 Pins 1 & 2
X6 Pins 15 & 16
X6 Pins 5,6 & 7
Modulating
valve
X6 Pins 8 & 9
Overheat stat
Fig. 9. Functional flow diagram.
Inputs
FAN
X4 Pin 3
X4 Pin 1
LOW VOLTAGE
ELECTRONICS
(Microcontroller)
RL1
PUMP
X3 Pin 1
Mains
indicator
X3 Pin 2
RL3
X5 Pin 3
GAS VALVE
F2 1.25AT
X5 Pin 1
RL4
ROOM STAT
6
5
FULL SEQUENCE
CONTROLLER
4
3
MAINS
PROGRAMMER/CLOCK
2
N
X2 1
Flame sense
Optional links
F1 2ATHRC
X1
3 2 1
L N
10
Spark
X5 Pin 2
N
N
Technical Helpline.
11. Installing The Appliance
Mark the centre-lines of the pipe connections to aid the preplumbing of the system pipework.
Check the position of the fixing points and the flue opening before
drilling the fixing holes 60mm deep for the No.12 size plugs and
cutting the flue duct hole at 110mm diameter (150mm diameter for
internally fitted flues.
11.5 Wall Mounting Plate and Manifold
Fit the plugs and fix the top support to the wall. Refer to Fig. 10.
Check the top support is properly aligned before tightening the screws.
11.6 Gas and Water Pipes
Remove the gas cock and fix the appropriate fitting to connect the
inlet pipe and re-fit.
Pre-plumbing is not recommended if no movement in the pipes is available.
If it is necessary for the pipes to run up the back of the appliance
then they must be arranged to pass behind the expansion vessel.
Pipework must not run horizontally within the limits of the casing.
It is important that the pipes are not fixed near the appliance using
clips that put a strain on the connections.
Before the appliance is fitted to the wall thoroughly
flush the system and mains water supply.
Note: READ THIS SECTION FULLY BEFORE COMMENCING
INSTALLATION.
11.1 General
The appliance is only suitable for fitting to a sealed system.
The flue must be installed as specified in BS5440:1.
Check that the appliance is suitable for the local conditions. i.e. gas
supply.
11.2 Unpacking
Remove the appliance from its packaging and check the contents
against the packing list.
11.3 Site Preparation
Check the correct position for the appliance has been chosen.
Refer to Sections 4 and 5.
Check that the wall is flat and and will support the weight of the
appliance.
11.4 Fixing Holes ad Flue Opening
Hold the template against the wall.
Check that the template is level.
Mark the position of the fixing holes and the flue opening. Refer to Fig. 10.
Fig. 10. Appliance mounting plate and flue position.
Mounting wall
Rear flue hall
110mm dia
(150mm dia for
internal fixing)
166mm
Side wall
Side flue
hole
110mm dia.
(150mm dia.
for internal
fixing)
60mm
Mounting
plate
Fixing holes Mounting
(alternatives) plate
Mounting wall
222mm
Appliance
casing
Appliance
casing
740mm
Rear flue position
Side flue position
400mm
11.7 Install the Boiler
Remove the cabinet by releasing the sides and lifting from the top
location.
Check that the gas and water valves are closed.
Lift the appliance to the wall, engage in the top support. Fix and
tighten the bottom screws. Refer to Fig. 10.
Tighten the gas and water connections.
Fit a discharge pipe to the relief valve leading it away from any
electrics or where it might be a hazard.
The pipe must not be less than 15mm in diameter and must run
continuously downward outside the appliance. Refer to Fig. 13.
Fig. 11. Marking out the side flue position.
Side flue hole
110mm dia.
(150mm dia. for
internal fixing)
Mounting wall
222
mm
166mm
Sid
ew
all
11
The standard telescopic flue assembly is suitable for flues
from425mm (without cutting) up to 725mm measured from the
centre-line of the boiler flue outlet to the outer face of the wall.
Refer to Fig. 14.
Fig. 12. Appliance casing and control
equipment fixings.
If L is greater than 725mm then flue extension kits will be
required - each kit extends the flue by 750mm up to a maximum
of 2500mm. See table below.
Side casing
fixing
screws (4)
Inner casing
cover
screws (4)
EXTENSION
1
2
3
MAXIMUM FLUE LENGTH mm
1475
2225
2500
11.9 Measure and Cut the Ducts
General: Cut the ducts as necessary, ensuring that the ducts are
square and free from burrs. Always check the dimensions before
cutting.
Measure the distance L. Refer to Fig. 16 and 17 .
Facia panel
fixing
screws (2)
The standard flue can be telescopically adjusted to any length
between 425mm and 725mm.
Fix the flue assembly together using the self-tapping screw
provided. Refer to Fig. 14.
Bottom facia
panel fixing
screws (3)
It will only be necessary to cut the standard assembly if L is less
than 425mm. Cut the flue turret assembly and the terminal
assembly by the same amount i.e L=350 - remove 75mm from
each assembly.
Minimum side flue length = 335mm
(accommodating a
10mm Service clearance and a 100mm wall)
11.8 Air and Flue Duct Preparation
The method of installation of the flue system may be varied to
suit the actual site conditions. The instructions for connecting
and fixing the ducts must, however, be strictly followed.
Minimum rear flue length = 322mm
100mm wall)
(accommodating a
If L is between
(1 extension)
(2 extension)
1175 - 1475mm
1925 - 2225mm
it is not necessary to cut the ducts.
Remove all packing material from the flue components.
Fig.14 . Standard flue assembly.
Fig. 13. Appliance pipework connections.
L
Turret
assembly
Fixing screw
Terminal
assembly
Appliance casing
(A)
(B)
100mm
(C)
36.5mm
(D)
(E)
(F)
A
B
C
D
E
F
Safety Relief
CH Flow
DHW Out
Gas Inlet
Mains Cold Water In
CH Return
=
=
=
=
=
=
50mm
95mm
160mm
225mm
290mm
355mm
12
Telescopic
adjustment
Fig. 15. Extension Duct.
L
Turret
assembly
Terminal
assembly
Fixing screws
Fixing screw
Ducts of equal length
Appliance casing
Shorten first extension fitted
to the turret assembly if more
than one extension is fitted
Fig. 17 . Rear flue.
Fig. 16. Flue duct length (side flue).
L
L
Terminal
assembly
Terminal
assembly
Flue
Turret
assembly
External
wall face
Indents
in line
with wall
face
Rear face of appliance
and face of mounting
wall
If L is between:
Make good the internal wall face and the external brickwork or rendering.
725 - 1175mm
1475 - 1925mm
2225 - 2500mm
(1 extension)
(2 extension)
(3 extension)
Replace the inner casing.
11.11 Fitting of the Flue Assembly without access to the Terminal
A rubber gasket kit is available from Worcester Heat Systems.
NOTE: A larger diameter opening in the wall is required. Refer to
Table 2.
it is necessary to shorten the assembly by cutting the first
extension duct assembly i.e. L = 1000mm - remove 175mm
from the air and flue ducts.
NOTE: Extension duct measurements do not include the
socketed end. Unless specifically instructed the socketed end
must not be removed.
Prepare the flue assembly as described in Section 11.9.
Fit the rubber sealing gasket centrally onto the terminal
assembly and tighten the clamp. Refer to Fig. 19.
Apply the plastic tape to the air duct in contact with the external
brickwork.
Fix the flue ducts together before fixing the surrounding air duct,
the cut ducts fit into the flue assembly.
From inside push the assembly through the wall so that the
gasket flange is against the outer face. Refer to Fig. 19.
It may be necessary to adjust the legs of the flue centering ring.
Align the flue turret and push fully onto the socket on the
appliance. Tighten the clamping ring and fix with the screw
provided. Refer to Fig 18.
Seal the gap around the duct at the inner wall face with the
flexible seal provided and make good.
Replace the inner casing.
11.10 Fitting the Flue Assembly with Access to the Terminal
Prepare the flue duct assembly as described in Section 11.9.
Apply the plastic tape to the air duct in contact with the external
brickwork.
From inside push the assembly through the wall. Align the flue
turret and push fully onto the spigot on the appliance. Tighten
the clamping ring and fix with the screw provided. Refer to Fig.
18.
13
Fig. 18. Flue Turret Fixing .
Fig. 19. Terminal assembly for internal
fitting of the flue.
1
5
1
2
3
1.
2.
3.
4.
4
3
4
2
Flue turret
Clamp
Appliance
Fixing Screw
1. Flue centering ring
2. Air duct
3. Flue duct
4. Rubber sealing gasket
5. Flue Terminal
Rubber sealing
gasket
11.12 Flue Bends
90° and 45° bends are available. A maximum of two bends may
be used in addition to the first bend on the flue turret.
A 90° bend is equivalent to 750mm of straight duct.
A 45° bend is equivalent to 375mm of straight duct.
Flue terminal
Clamping ring
Z
Fig. 20. Flue bends.
Air Z – 81mm
Flue Z – 51mm
Y – 162mm
(plain tube)
Y
X
of the terminal assembly i.e Z=350mm - remove 75mm from the
terminal assembly.
If Z in 425 - 725mm it is not necessary to cut the terminal
assembly or use a second extension duct as the length can be
set telescopically.
If Z>725mm then two extension duct assemblies will be
required, the first assembly being cut to length as plain tubes.
A maximum flue assembly of 2.5m is possible with 1 X 90° bend
and 2m with 2 X 90° bends.
Measure the lengths X,Y and Z. Refer to Fig. 20.
The maximum value of X using the turret assembly only is
506mm. Reduce the ducts to the appropriate length i.e. X =
406mm, cut 100mm from the air duct and 120mm (to cover the
entry into the 45° or 90° elbow) from the flue duct. Refer to
Fig.21.
NOTE: The flue system ducts between the elbows, dimension Y,
requires the socketed ends (of the first extension if two or more
are used) to be removed and the air and flue tubes to be cut to
the same length.
Cut the ducts to a length Y - 162mm. Refer to Fig. 20.
The final section, dimension Z, of the flue system must include a
section of plain duct assembly i.e . an extension assembly with
the sockets removed. Reduce the final section, including the
terminal assembly, by the appropriate amount i.e. Air duct Z 81mm and the flue duct Z - 51mm. Refer to Fig. 20.
If more than two extension ducts are needed in any section to
achieve the required length then the final section of the
assembly must not be less than 325mm without cutting the
terminal assembly.
NOTE: The flue duct of the final extension must be 30mm longer
than the air duct.
Each section must be connected to the previous section of the
flue bend by fixing the flue ducts together and then similarly
fixing the air ducts which engage the elbows.
Fit the assembly as described in Section 11.10, 11.11 as
appropriate.
Make good the internal and external brickwork or rendering.
If Z<425mm it will be necessary to cut the air and flue ducts of
the extension to a plain length of 100mm and reduce the length
14
Fig. 21 - Elbow to Flue Turret
Assembly.
Fig. 23 - Facia Connections Cover.
120mm
1
2
100mm
Flue Turret
Bend
3
1. Control Panel Fixing Screws
2. Facia
3. Control Panel Pivot Point
4. Connection Cover
5. Connection Cover Fixing
Screws
Fig. 22 Vertical Adapter.
Flue Duct
Air Duct
5
4
11.14 Completion of the Installation
Check that all the connections on the appliance have been
tightened.
Remove the facia bottom panel. Refer to Fig. 23.
Connect the mains electricity supply lead to the appliance and
secure the cable clamp. Refer to Fig. 23. and 24.
Check there is sufficient loose lead to allow the release of the
facia panel assembly and that the earth lead of the mains supply
cable is longer than the live and neutral leads.
Adapter
Clamp
Fit the facia mounted clock. Full instructions are sent with the
programmer.
Flue Spigot
Connect any external controls ensuring that the leads pass
through the appropriate clamps. Refer to Fig.25.
11.13 Vertical Adapter for Horizontal Flues
An adapter is available for an initial short section of vertical flue.
Refer to Fig. 22.
Measure and cut the flue as described in Section 11.12.
The first, vertical, section (equivalent to dimension X) is
measured from the top of the boiler casing. Cut the vertical
section of the extension duct to 167mm less than the measured
distance. Do not remove the socketed ends.
The minimum measured distance is 167mm.
Seal the air duct to the turret using silicone sealant.
Fix the adapter with the clamp and screw provided.
Test for gas soundness as described in BS6891.
If the appliance is not to be commissioned immediately, replace
the cabinet and facia bottom panel. Check that the gas and
electricity services have been turned off.
If the premises are to be left unoccupied during frosty conditions
then drain the appliance and system. For short inoperative
periods, leave the appliance under the control of the built-in frost
thermostat or the remote frost thermostat (if fitted) or leave
operation continuously with the room thermostat set at 6°C.
Fig. 24 Fig. 25. Mains electricity connections.
230V
N
X1
L
X2
Blue
Brown
N. L.
Mains
RN RI RL
Room Thermostat
Fuse 2A Slow Blow
Earth
CN CI CL
Programmes
Strain relief clamp
Fan
Green/yellow
Pump
Gas Valve
15
Programmer and room thermostat
strain relief clamps
12. Commissioning The Appliance
Fig. 27. Appliance components and fixings
(upper assembly).
Flue hood
Benchmark Water Treatment: For optimum performance after
installation, this boiler and its associated central heating
system should be flushed in accordance with the guidelines
given in BS7593:1992 - Treatment of water in domestic hot
water systems. Full instructions are supplied with proprietary
cleansers sold for this purpose. If an inhibitor is to be used
after flushing, it should be used in accordance with the
inhibitor manufacturers instructions.
Suitable flushing agents and inhibitors are available from Betz
Dearborn Tel: 0151 4209563 and Fernox Tel: 01799 550811.
Instructions for use are supplied with these products.
Fan assembly
fixing screws (4)
Overheat
thermostat
Auto air
vent
12.1 SUMMARY
The appliance is dispatched with the controls set to provide a
maximum output for domestic hot water and central heating of
23.4 kW (80,000 Btu/h). The appliance automatically modulates
to satisfy lower heat loads.
Domestic Hot Water and Central Heating Systems. Check that
both the mains water supply and central heating systems have
been fully flushed out at installation.
Combustion
chamber
cover fixing
clips (2)
Burner fixing
screws (2)
Fig. 26. Appliance casing and control
equipment fixings.
Inner casing
cover
screws (4)
Flue Gas
Test Point
access. Refer to Section 14.3(c).
Set the Expansion Vessel Pressure
The charge pressure of the expansion vessel as dispatched is 0.5 bar,
which is equivalent to a static head of 5 metres (17ft). The charge
pressure must not be less than the static head at the point of
connection. A Schraeder 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
lb/ins2) and check for water soundness. Release water from the
system using the relief valve test knob until the initial System
Design Pressure is obtained, up to a maximum of 1.5 bar.
Initial System Design Pressure (bar) = Expansion Vessel Charge
Pressure +0.3 (bar).
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.
Side casing
fixing
screws (4)
Facia panel
fixing
screws (2)
Fig. 28. Pressure relief valve.
Bottom facia
panel fixing
screws (3)
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
appliance are off.
Check that all the water connections throughout the system are
tight.
Open the system valves at the appliance. Open all the radiator
valves, fill the system and vent each radiator in turn.
Remove the inner casing cover as described in section 14.3(b).
See Fig 26.
The automatic air vent will vent the appliance. Check that the air
vent cap has been removed. See Fig. 27.
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. 28. Lower the control box to gain
Pressure relief
valve.
(Turn knob
anti-clockwise
to test).
16
If the pressure indicated on the pressure gauge is greater than
2.6 bar when operating at the maximum central heating
temperature, an extra expansion vessel must be fitted to the
system as close as possible to the appliance central heating
return connection.
The appliance (as dispatched) can accommodate a system
volume of about 100 litres. Refer to BS 7074 Part 1. If the system
volume is in excess of that accommodated by the expansion
rises. Fully close the tap and check that the burner goes off. The
fan may continue running until the appliance has cooled.
Central Heating
Check that all the radiator valves are open.
Check that the system is pressurised and set to the required
pressure as indicated on the gauge.
Set any Programmer to HEATING & WATER.
Turn on the gas and electricity supplies.
Set the room thermostat and the Central Heating Temperature
Control to maximum.
The burner will light.
The appliance will modulate its output between 7.5 and 23.4 kW
over a period of about twenty minutes.
Check the system to ensure that all the radiators are heating up
evenly.
Shut down all but one of the radiators and observe the burner
pressure fall. Open all of the radiator valves and check that the
burner pressure rises.
Balance the system so that the required temperature difference
across the central heating flow and return pipes is obtained. See
Table 3, Section 3 Data Tables.
Set the room thermostat to minimum and check that the burner
goes out. Reset the room thermostat to maximum and the
burner will re-light after a short anti-cycle delay and follow the
normal operating procedure.
Check for proper ignition of the burner after a break in the gas
supply. Turn off the gas service cock and wait for 60 seconds. The
burner will go out but sparking from the electrode will continue
for 10 seconds when the appliance will enter a “lockout” state.
Carefully open the gas service cock, interrupt the mains power
supply to the appliance for a few seconds to reset the controls
and observe the burner re-light and follow the normal sequence
of operation.
Turn off the gas service cock and the electrical supply to the
appliance.
Drain the system while the appliance is still hot.
Refill, vent and re-pressurise as described in Section 12.2.
Domestic Hot Water and Central Heating
Turn on the electricity supply to the appliance and open the gas
supply cock at the appliance.
Set the Central Heating temperature control knob to demand
and any programmer to HEATING & WATER. If a programmer is
fitted, set the domestic hot water to Continuous or 24 Hrs 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 after a
short delay fully heated hot water is discharged from the tap.
Close the tap and the burner will go off. After a short time the
appliance will then return to the central heating mode and
automatically balance with the system requirements.
Set the Central Heating Temperature Control Knob 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 users requirements.
If the appliance is to be left inoperative, check that the Central
Heating Temperature Control 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. If the premises are to be left unoccupied during frosty
conditions, then drain the appliance and system. For short
inoperative periods, leave the appliance under the control of the
built in frost thermostat or the remote frost thermostat (if fitted)
or leave operating continuously with the room thermostat set at
6°C.
Fig. 29. Gas valve.
Main gas valve
connections
(Black : blue : brown :
green/yellow)
Minimum
pressure
adjuster
Maximum pressure
adjuster
Note: Clockwise to
increase and anticlockwise to
decrease the
pressure
Burner pressure
test point
Inlet pressure test
point
Electrical connections –
modulator (Blue : Blue)
Modulating
solenoid
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 specified
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.
12.4 APPLIANCE OPERATION
Turn off the gas and electricity supplies to the appliance.
Undo the two screws and hinge down the facia.
Loosen the burner pressure test point screw and connect a
pressure gauge. See Fig. 29.
Domestic Hot Water.
Set any Programmer to HEATING & WATER.
Turn on the gas and electricity supplies.
Set the Central Heating temperature control knob to Off.
A tap should be opened to create a hot water demand then a
continuous ignition spark will occur until the burner is alight and
sensed by the control circuit. The burner will light and remain at
its maximum setting. The burner pressure should be between
13.4 and 13.8 mbar on Natural gas (33.0 and 35.0 mbar on
Propane). If the burner pressure is low, check that the supply
pressure at the gas valve inlet is at least 19 mbar for Natural gas
(37 mbar for Propane).
Test for gas soundness at the joint between the burner and the
gas valve with leak detection fluid.
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.
Gradually close the hot tap and check that the burner pressure
drops. Fully open the tap and check that the burner pressure
17
13. Instructions To The User
14. Inspection And Service
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 heating system is not to be
used in frosty weather.
13.3 Tell the user the sealed system set pressure.
13.4 Tell the user of the importance of regular servicing.
Worcester Heat Systems Ltd. offer a comprehensive maintenance
contract.
13.5 Set the system controls to the user’s requirements.
13.6 If an external programmer has been fitted which has a
programmable domestic hot water facility then it is suggested
that this be set to Continuous or the equivalent.
13.7 Complete and hand over to the user the Benchmark
Log-Book.
14.1 SERVICING
To ensure continued efficient operation of the appliance 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 engineers
such as British Gas or Corgi registered personnel.
14.2 PRE-SERVICE INSPECTION
Check that the flue terminal and the terminal guard, (if fitted), are
clear.
If the appliance is in a compartment, check that the ventilation
openings in the compartment door or walls are clear. See Section
6 - Air Supply.
Check the system and remake any joints or fittings which show
signs of leakage.
Refill, vent and re-pressurise as described in Section 12.2.
Operate the appliance and the system taking note of any faults.
Measurement of the Flue Gases
For consistency of results of the flue gas measurements it is
necessary to have a constant output and for the appliance to be
at equilibrium.
Turn on a tap to create a hot water demand.
Wait until the appliance reaches thermal equilibrium (approx. 10
minutes).
Remove the test point sealing screw on the appliance top panel.
See Fig. 32.
Connect to the test point with a piece of tubing.
Expected measurements should be between:
Fig. 30. User controls.
Reset button
Mains indicator
System
pressure
gauge
C.H. temperature control
and on/off knob
Equivalent flue
length (metres)
Carbon
Dioxide (%)
Carbon
Monoxide (%)
0.5
6.9
0.0008
1.0
7.0
0.0009
1.5
7.1
0.0010
2.0
7.3
0.0012
2.5
7.4
0.0013
Equivalent flue
length (metres)
Carbon
Dioxide (%)
Carbon
Monoxide (%)
0.5
7.9
0.0017
1.0
8.0
0.0020
1.5
8.2
0.0024
2.0
8.5
0.0030
2.5
8.8
0.0035
For Natural Gas:
For Propane:
When calculating the equivalent flue length a flue bend is
equivalent to 750mm of straight flue.
After taking the measurement replace and tighten the sealing
screw.
IMPORTANT
Disconnect the electrical supply at the mains and turn off the
gas supply at the gas service cock on the appliance before
servicing.
After completing the service always test for gas soundness as
indicated in BS 6891.
18
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.
(d) Bottom panel. Unclip and remove the appliance bottom
panel.
(e) Fan. Remove the inner casing cover. Carefully unplug the
electrical connections and pull off the sensing tubes. Unscrew
the four fixing screws and remove the fan assembly. See Fig. 32.
(f) Combustion Chamber Front. Remove the inner casing cover.
Undo the spring clips fixing the combustion chamber front. See
Fig. 32.
(g) Flue Hood Assembly. Remove the fan assembly. Remove the
combustion chamber front. Lift and slide the flue hood assembly
from the appliance. See Fig. 32. When refitting the hood ensure
that the rear return edge passes under the lip at the rear of the
combustion chamber.
(h) Burner Assembly. Remove the combustion chamber front.
Pull off the two spark electrode leads and disconnect the flame
sense lead. Undo the burner fixing screws. Lift up and remove
the burner assembly from the appliance. See Fig. 33.
Fig. 31. Appliance casing and control
equipment fixings.
Inner casing
cover
screws (4)
Side casing
fixing
screws (4)
Fig. 33. Burner and electrode assembly.
Facia panel
fixing
screws (2)
Injector
Bottom facia
panel fixing
screws (3)
(a) Cabinet Front Panel. Remove by lifting off the supports.
(b) Inner Casing Cover. Check that the electricity supply to the
appliance is turned off. Remove the cabinet front panel. Unscrew
the four screws securing the cover to the casing and lift off. See
Fig. 31.
(c) Facia Panel. Check that the electricity supply to the appliance
is turned off. Remove the cabinet front panel. Unscrew the two
upper screws as shown in Fig. 31. and hinge down the facia
taking care not to damage the pressure gauge capillary tube or
electrical connections.
Spark electrode
14.4 SERVICE OF COMPONENTS
Clean the Fan. Any dust or fluff should be removed with a soft
brush or by blowing. Take care not to distort the pressure
sensing device.
Clean the Main Burner. Brush the blade tops and mixing tube
with a soft brush and check that all the flame ports are clear.
Remove any blockages with a non-metallic brush. Inspect the
injector and clean with a soft brush. Replace the injector if it
appears damaged. Do not use a wire brush or anything likely to
cause damage. Replace the spark and sense electrodes if they
appear damaged.
Clean the Gas to Water Heat Exchanger. Clean the heat
exchanger using a soft brush. Remove the deposits from the
bottom of the combustion chamber. Do not distort any of the
blades.
Combustion Chamber Insulation. Examine and replace any
pads that are damaged. Remove any dust or deposits using a
soft brush.
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 operation
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
appliance as described in Section 12 - Commissioning.
Refit the cabinet front panel and reset the controls to the users
requirements.
Fig. 32. Appliance components and fixings
(upper assembly).
Flue hood
Flue Gas
Test Point
Fan assembly
fixing screws (4)
Overheat
thermostat
Auto air
vent
Combustion
chamber
cover fixing
clips (2)
Burner fixing
screws (2)
19
2. Air Pressure Switch. See Fig. 36.
Check that the electricity supply to the appliance is turned off.
Remove the cabinet front panel as described in Section 14.3 (a)
and lower the facia. Section 14.3(c).
Carefully pull off the sensing tubes and the electrical connections
from the switch. Remember to note their positions.
Unscrew the two screws behind the Air Pressure Switch and
remove the switch from the appliance.
Fit the replacement switch in the reverse order ensuring that the
electrical connections have been made to the correct terminals
on the switch. Check that the sensing tubes are fitted correctly.
3. Fan. See Fig. 32.
Check that the electricity supply to the appliance is turned off.
Remove the fan assembly as described in Section 14.3(e).
Fit the replacement fan in the reverse order.
4. Overheat Thermostat. See Fig. 32 and 34.
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 off the two wires from the thermostat head.
Undo the retaining nut on the top of the appliance and remove
the retaining clip from the heat exchanger. Carefully withdraw
the thermostat from the appliance.
Fit the replacement thermostat in the reverse order ensuring that
some heat sink compound is between the thermostat and the
heat exchanger.
5. Gas to Water Heat Exchanger. See Fig. 34.
Check that the electricity supply to the appliance is turned off.
Drain the central heating circuit and domestic circuits as
described in Section 15.3 (a) and (b).
Remove the inner casing cover, fan, flue hood assembly,
combustion chamber front, overheat thermostat, automatic air
vent and combustion chamber side insulation as described in
Sections 14.3 (b, e, f and g), 15.4 (1) and 15.4 (4).
Fit the replacement heat exchanger in the reverse order ensuring
that all the fibre washers are correctly fitted and a layer of heat
sink compound is on the thermostat.
Open the valves and fill and re-pressurise the system as
described in Section 12.2.
15. Replacement Of Parts
15.1 IMPORTANT
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 may also need to be
hinged down as described in Section 14.3 (c).
15.3 DRAINING THE APPLIANCE
Check that the electricity supply to the appliance is turned off.
Before removing any component holding water it is important
that as much water as possible is removed from the appliance.
(a) Central Heating Circuit. Turn off the central heating flow and
return valves at the appliance. Open the pressure relief valve,
make sure that the dust cap on the auto air vent is removed. See
Fig. 32. Close the pressure relief valve when the flow has
stopped. Some water will remain in the expansion vessel, pump
and Gas to Water heat exchangers 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 and open the lowest hot water tap. A
quantity of water will remain in the Gas to Water heat exchanger,
extra care must be taken when removing this component.
15.4 COMPONENT REPLACEMENT
1. Automatic Air Vent. See Figs. 32. and 34.
Remove the inner casing cover as described in Section 14.3 (b).
Drain the central heating circuit as described in Section 15.3 (a).
Unscrew air vent from the heat exchanger.
Fit the replacement assembly ensuring thread sealant is applied
and the dust cap is removed.
Open the valves and fill and re-pressurise the system as
described in Section 12.2.
Fig. 34. Combustion chamber.
Auto air
vent
Overheat
Thermostat
Heat
exchanger
Hot water
connections
Central heating
connections
Cut-outs in
combustion
chamber sides
Pump bulk-head
connector
Flame Sense Electrode
Spark Electrode Assembly
20
Burner
Restart the appliance in central heating mode and adjust the
minimum adjustment screw on the gas valve to give a pressure
of 1.0 mbar on natural gas or 3.5 mbar on propane. See Fig. 35.
After completing the adjustments, check the minimum and
maximum pressures and re-adjust as necessary. Once this has
been done the clear cap should be re-fitted to the adjuster and
the retaining screw tightened. Coat the screw with paint or nail
varnish to prevent user adjustment.
6. Combustion Chamber Insulation.
Check that the electricity supply to the appliance is turned off.
Drain the central heating circuit as described in Section 15.3(a).
Remove the inner casing cover, fan, flue hood assembly, burner,
and Gas to Water heat exchanger as described in Sections 14.3
(b, e and f), and 15.4 (5). Remove the fibre insulation pads from
the combustion chamber side, rear, and front sections.
Fit the replacement pads in the reverse order taking care not to
damage them.
Open the valves and fill and re-pressurise the system as
described in Section 12.2.
7. Burner. See Fig. 33.
Check that the electricity and gas supplies to the appliance are
turned off.
Remove the burner assembly as described in Section 14.3 (h).
Fit the replacement burner in the reverse order taking care not to
damage the electrode leads.
8. Burner Injector. See Fig. 33.
Remove the burner as described in Section 14.3 (h).
Unscrew the brass injector from the manifold.
Fit the replacement injector in the reverse order.
9. Spark Electrode Assembly. See Fig. 33a.
Remove the combustion chamber front as described in 14.3 (g)
Carefully pull off the two electrode leads,
Undo the M4 extended nut and remove the spark electrode
assembly from the burner.
Fit the replacement electrode in the reverse order, checking that
the spark gap is 3.5 to 4.5mm.
Fig. 29. Gas valve.
Main gas valve
connections
(Black : blue : brown :
green/yellow)
Maximum pressure
adjuster
Note: Clockwise to
increase and anticlockwise to
decrease the
pressure
Minimum
pressure
adjuster
Burner pressure
test point
Fig. 33a. Spark electrode assembly.
Inlet pressure test
point
3.5-4.5mm
2.5-5mm
Electrical connections –
modulator (Blue : Blue)
Modulating
solenoid
12. Central Heating Sensor. See Fig. 36.
Check that the electricity supply to the appliance is turned off.
Hinge the facia assembly in the servicing position as described in
Section 14.3(c and d).
Carefully pull off the two leads from the sensor.
Pull off the sensor and spring retaining clip from the pipe.
Fit the replacement sensor in reverse order with a layer of heat
10. Flame Sensor. See Fig. 33.
Remove the burner as described in sections 14.3(h) and 15.4(8).
Undo the M3 screw and remove the sense electrode from the
burner.
Fit the replacement electrode in the reverse order, checking that
the sense gap is 5 to 6mm.
11. Gas Valve. See Figs. 35. and 36.
Check that the electricity and gas supplies to the appliance are
turned off.
Hinge down the control box assembly in the servicing position
as described in Section 14.3(d).
Whilst supporting the valve unscrew the plug retaining screw
and carefully pull off the electrical solenoid plug connection and
the two modureg leads.
Undo the 8 manifold screws and remove the gas valve. See Fig. 36.
Fit the replacement gas valve in the reverse order ensuring the
“O” rings are correctly fitted.
Turn on the gas supply and check for soundness.
To set the burner pressure. See Fig. 35.
The minimum and maximum burner pressures must be set after
a new gas control has been fitted.
The maximum burner pressure must be set first, as any
adjustment of the maximum pressure influences the minimum
pressure setting.
Start the appliance in the domestic hot water mode as described
in section 12.4. - Appliance Operation.
Adjust the maximum pressure adjustment screw on the gas
valve to give a burner pressure of 13.6 mbar on natural gas, for
propane the maximum pressure adjustment must be increased
to maximum clockwise, this should give 33.0 - 35.0 mbar.
End the demand and reset the appliance by interrupting the
mains electricity supply. (Otherwise there is a four minute anticycle delay at the end of a demand).
Fig. 36. Gas valve pump and air pressure
switch
1 2
3
4
9
1
2
3
4
5
6
21
Pressure relief valve
Domestic hot water sensor
Water flow turbine
Gas valve
Pump
Air pressure switch
5
10
12 8
6
11 7
7 Air pressure switch connecting tubes
8 Pressure gauge connection
9 Gas valve electrical connections
10 By-pass pipe
11 Fixing disc and screw
12 Central heating sensor
sink compound between the faces. Refit the leads.
13. Domestic Hot Water Sensor.
Check that the electricity supply to the appliance is turned off.
Hinge the facia assembly in the servicing position as described in
Section 14.3(c and d).
Carefully pull off the two leads from the sensor.
Undo and remove the clamping screw.
Pull off the sensor and spring retaining clip from the pipe.
Fit the replacement sensor in the reverse order ensuring a layer
of heat sink compound is between the faces. Refit the leads.
14. Circulating Pump. See Figs. 34 and 36.
Check that the electricity supply to the appliance is turned off.
Drain the central heating circuit as described in Section 15.3(a).
Hinge the facia assembly in the servicing position as described in
Section 14.3(c).
Undo the two union nuts and the pipe to the expansion vessel,
remove the pump from the pipe-work. Support the pump and
remove the electrical cover.
Disconnect the electrical wires taking note of their positions.
Fit the replacement pump in the reverse order using new sealing
washers.
(Alternatively replace the pump head only by removing the four
Allen screws on the pump, remove the head and support whilst
removing the electrical connections. Refit the new head).
Open the valves and fill and re-pressurise the system as
described in Section 12.2
Note: The direction of flow should be upwards. The speed should
always be set to maximum.
15. Expansion Vessel.
Drain the central heating circuit as described in Section 15.3(a).
Isolate the gas supply at the mains.
Then either fit a separate expansion vessel on the central heating
return to the appliance or replace the existing vessel as
described below.
Drain the domestic circuit as described in Section 15.3(b).
Disconnect the flue system at the boiler.
Disconnect the appliance pipework at the appliance entry points
ensuring precautions are taken to cope with any water
remaining in the appliance.
Remove the appliance from the wall.
Disconnect the expansion vessel from the appliance by undoing
the fitting nut at it’s base.
Fit the replacement vessel in the reverse order.
Open the valves and fill and re-pressurise the system as
described in Section 12.2
16. Pressure Relief Valve. See Fig. 37.
Drain the central heating circuit as described in Section 15.3(a).
Hinge down the facia assembly as described in Section 14.3(c)
Remove the Bottom panel as described in Section 14.3(d)
Undo the discharge pipe connection and remove the valve
retaining clip. Remove the valve taking care not to distort the
pipework.
Fit the replacement valve in reverse order. Reconnect the
discharge pipe.
Open the valves and fill and re-pressurise the system as
described in Section 12.2
17. Water Flow Switch. See Fig. 38.
Check that the electricity supply to the appliance is turned off.
Drain the domestic hot water circuit as described in Section
15.3(b).
Remove the two upper screws and hinge down the facia panel as
described in Section 14.3(c).
Undo the two union nuts securing the “T” piece and remove the
housing from the pipework.
Disconnect the electrical connection.
Fit the replacement water flow switch in the reverse order
ensuring new fibre washers are fitted to the new switch body.
Fig. 38. Water Flow Switch. (Side View)
Flow Restrictor
Water Flow Switch
“T” Piece
Fig. 37. Pressure relief valve.
18. Domestic Hot Water Flow Restrictor. See Fig. 38.
Remove the water flow switch as described in Section 15.4-17.
Undo the two union nuts securing the “T” piece and remove the
housing from the pipework.
The plastic flow restrictor is located within the “T” piece on the
water flow switch.
Fit the replacement flow restrictor and reassemble in the reverse
order ensuring the fibre washers are in place.
19. Pressure Gauge.
Check that the electricity supply to the appliance is turned off.
Drain the central heating circuit as described in Section 15.3(a).
Remove the two upper screws and hinge down the facia panel as
described in Section 14.3(c).
Prize back the retaining clips securing the gauge to the facia
panel remove wire clip and unplug the gauge from the pump
inlet pipe.
Fit the replacement gauge in the reverse order ensuring the “O”
ring is in place.
Open the valves and fill and re-pressurise the system as
described in Section 12.2
Pressure relief
valve.
(Turn knob
anti-clockwise
to test).
22
20. Control Board.
Check that the electricity supply to the appliance is turned off.
Undo the 3 screws and remove the facia bottom panel.
Remove the two upper screws and hinge down the facia
assembly.
Carefully pull off all the connectors. Disconnect the mains supply
lead at terminal X1 and the earth connection at the back.
Remove the four corner screws on the back of the facia and
separate the metal back panel from the plastic facia.
Remove and retain the brass nut and washer.
Release the six pillars on the control board and pull the control
board forward off the back panel.
Fit the replacement board in the reverse order ensuring it is
pushed firmly onto the six pillars and clicks into place. Special
care should be taken with the brass post and nut to ensure a
good earth contact. (Check earth continuity between the
incoming earth and the appliance chassis).
Refit the facia panel and hinge the control box assembly in the
servicing position as described in Section 14.3 (c).
21. Gauze filter. See Fig. 39.
Remove the water flow switch as described in section 15.4-17.
Undo the lower union nut on flow switch housing.
Undo the nut on the isolating valve and remove the mains water
inlet pipe. Carefully extract the filter from the valve end of the pipe.
Replace the filter and refit the pipe in reverse order using a new
fibre washer.
22. Flue flow sensor. See Fig. 40.
Check that the electricity supply to the appliance is turned off.
Remove the fan assembly as described in Section 14.3(e).
Unscrew the single central retaining screw and withdraw the
sensor from the fan.
Fit the new sensor ensuring the correct orientation and carefully
tighten the retaining screw.
Refit the fan assembly in reverse order.
Fig. 39. Gauze Filter.
Gauze Filter
Fibre Washer
Isolating Valve
Fig. 40. Flue flow sensor.
Positive
5. Refit the end cap ensuring the bracket is in the correct orientation.
6. Refit the burner to the appliance and re-assemble the inner
casing.
7. Follow the dismantling instructions to remove the gas valve
and refit the new valve. See Installation Instructions: Section
15.4.11 Replacement of Parts, Component Replacement, Gas
Valve.
8. Turn on the gas and electricity supplies and following the
commissioning procedure confirm gas soundness and correct
boiler operation.
9. Set the gas pressure to the required rate for the new gas type
as specified on the data plate. When this is done refit the cap to
the adjuster and seal its retaining screw with paint or nail varnish.
10. Turn off the boiler and when cool peel off the arrow from
the data plate and re-stick it against the gas type for which the
appliance is now converted.
11.Replace the boiler front panel.
16. Conversion Instructions
These instructions should be used when converting appliances
from natural gas to LPG and vice versa.
Only components supplied by Worcester Heat Systems should
be used.
Only competent persons should attempt the conversion.
Conversion from Natural Gas to LPG should not be carried
out on appliances installed in a room or internal space below
ground level.
1. Ensure the gas service cock is turned OFF and the electrical
supply is isolated.
2. Refer to section 14.3 Dismantle the Appliance to remove the
boiler front panel and inner casing. Follow the dismantling
instructions to remove the burner.
3. Remove the injector and replace with the injector from the
kit.
4. Remove the nut, end cap and bracket from the end of the
burner.
4.1 For conversion to Natural gas remove the internal gauze.
4.2 For conversion to LPG fit the gauze into the burner body.
The conversion is now complete.
Parts List
Item No.
Description
Natural Gas to LPG Kit
7 716 192 131
8 716 140 209
Stereomatic 2.78mm
1.
Burner Injector
2.
Burner Gauze
8 716 142 601
Remove Gauze
3.
Gas Valve
8 716 142 430
8 716 142 413
4.
Copper Washer
8 716 101 994
8 716 101 994
23
LPG to Natural Gas Kit
7 716 192 132
8 716 105 033
Stereomatic 4.3mm
24
Pump on
Water flow
temperature
monitored by central
heating sensor
Escape pause by
resetting the mains
electricity supply
OFF-ON
Is fan in
overrun mode?
YES
NO
Wait (pump on
in central
heating mode)
FAIL
Air pressure
switch test
PASS
AUTOMATIC START-UP SEQUENCE
Internal
"Autofrostat"
demand
CENTRAL HEATING
DEMAND
Operating Switch
(or programmer)
and room
thermostat on
End of a domestic
hot water overrun
1. Central Heating Mode
Fan ON
Sense air
pressure
Wait
(fan or fan and
pump on)
ABSENT
AUTOMATIC
START-UP
SEQUENCE
Anti-cycle delay
PRESENT
Burner pressure
1.0 mbar for 60
seconds.
Main gas valve
OFF
Main valve
opens
Initiate
sparking
17. Operational Flow Diagrams
Ignition Time out (after 9secs)
ABSENT
Sense
flame
Stop
sparking
Burner pressure
automatically
adjusted for range
rating and then
modulated to
maintain set flow
temperature
6
Central heating
temperature 5°C
above set point
Ignition
Lock-out
Wait
(fan or fan and
pump on)
PRESENT
CENTRAL
HEATING
DEMAND
SATISFIED
EITHER
Operating Switch
(or programmer)
OFF
Fan overrun
4 minutes
Continue
pump overrun
for 6 secs pump
pulse after
2 minutes.
Gas valve OFF
Room thermostat
OFF
25
Inhibit operations
for approximately
1 second. 6 second
delay before reignition from any
other demand.
Run pump
Burner pressure
at 1.0 mbar
4°C to 8°C
6
Above 8°C
At the set point
change to a wide
band proportional
control
Return to normal
OFF state
Pump OFF
Is the central
heating mode
interrupted?
Wait for hot water
temperature to
drop to factory
pre-set level
Burner never to be
extinguished
irrespective of the
rate of temperature
rise
Monitor central
heating sensor
Below 4°C
Commence normal central
heating mode until heating
temperature reaches 20°C
Domestic hot water
temperature
monitored by hot
water sensor
Burner pressure adjusted
based on the temperature
rise over the previous
minute. Aiming at 4°C
rise/minute.
6. Central Heating ramp control
Internal
"Autofrostat"
Demand
No demand and
primary
temperature below
6°C monitored by
the central heating
sensor
3. "Autofrostat" Function
HOT WATER
DEMAND
(Overrides all other
overrun modes
and functions)
Signal from the
flow switch
2. Domestic Hot Water Mode
AUTOMATIC
START-UP
SEQUENCE
Gas valve OFF.
Fan remains ON
End of demand or central
heating temperature above
70°C monitored by the
central heating sensor
Fan on for
4 minutes
6 second pump pulse with a
2nd 6 second pump pulse 2
minutes later.
5. Fan Overrun Function
End of hot water demand
with no central heating
demand. Hot water
thermistor above 40°C
No demand and central
heating temperature above
50°C monitored by the
central heating sensor
Fan overrun
4 minutes
Pump pulse 6
seconds then 2
minutes later
2nd pulse
Gas valve OFF
Pump on until
primary temperature
drops to 50°C
HOT WATER
DEMAND
SATISFIED
Operating
Switch (or
programmer
OFF)
4. Pump Overrun Function
Modulate heat
input to maintain
hot water
temperature at the
factory pre-set
level
Hot water
temperature above
70°C
CH control POT
DHW temp. sensor
CH temp. sensor
X6 Pins 3 & 4
Flow signal
Outputs
X6 Pins 19 & 20
Air pressure switch
X6 Pins 1 & 2
X6 Pins 5,6 & 7
Modulating
valve
X6 Pins 15 & 16
X6 Pins 8 & 9
Overheat stat
18. Fault Finding
Inputs
FAN
X4 Pin 3
X4 Pin 1
LOW VOLTAGE
ELECTRONICS
(Microcontroller)
RL1
PUMP
X3 Pin 1
Mains
indicator
X3 Pin 2
RL3
X5 Pin 3
GAS VALVE
F2 1.25AT
X5 Pin 1
RL4
ROOM STAT
6
5
FULL SEQUENCE
CONTROLLER
4
3
MAINS
PROGRAMMER/CLOCK
2
N
X2 1
Flame sense
Optional links
F1 2ATHRC
X1
3 2 1
L N
26
Spark
X5 Pin 2
N
N
Fault in
Domestic Hot Water
Fault in
Central Heating
Is mains LED flashing?
YES
GO TO
CHECK D
YES
NO
NO
Is mains LED
illuminated?
NO
GO TO
CHECK C
NO
Is mains LED
iluminated?
YES
YES
Is control knob
set for demand?
Is mains LED flashing?
NO
Turn control knob
fully clockwise
NO
Ensure link is fitted at
X2 pins 5 & 6
NO
Set room stat to
call for heat
NO
Ensure link is fitted at
X2 pins 2 & 3
YES
Is a room thermostat
fitted?
YES
Is room thermostat
calling for heating?
YES
Is programmer fitted?
GO TO
CHECK O
YES
Is programmer calling
for heat?
YES
NO
Set clock to call for heat
YES
Is pump running?
NO
GO TO
CHECK F
YES
GO TO
CHECK E
YES
Has overheat
thermostat tripped?
YES
Has overheat
thermostat tripped?
NO
NO
GO TO
CHECK K
GO TO
CHECK K
27
No mains LED
Is mains present at
X1 pins 1 & 3?
NO
Connect mains
supply
YES
Is F1 (2ATHRC) OK?
NO
Replace fuse
YES
Is F2 (1.25AT) OK?
NO
Replace fuse
YES
Faulty PCB
Replace
Flashing mains LED
Remove X6
Is resistance between
pins 3 & 4 between
690ohms & 33k?
NO
YES
Is resistance between
pins 19 & 20 between
690ohms & 33k?
YES
Open circuit?
NO
Short circuit
YES
NO
GO TO
CHECK H
Faulty
Replace thermistor
Faulty
OK
GO TO
CHECK I
OK
Faulty PCB
Replace
28
GO TO
CHECK H
OK
Faulty
Replace harness
Faulty
GO TO
CHECK J
OK
Overheat Thermostat Check
The overheat thermostat can be
reset by pressing the reset button,
but if it trips immediately or on a
regular basis a serious problem has
occurred therefore contact your
installer
Reset thermostat
Does button hold in?
NO
Is capillary broken?
YES
YES
Is capillary firmly
ATTACHED
to exchanger?
NO
Replace overheat
thermostat
ATTACH to heat
exchanger
YES
GO TO
CHECK I
Pump Check
Is pump connector
secure on the PCB (X3)?
NO
Secure Connector
YES
Is mains present at the
pump connector
(X3 pins 1 & 2)?
NO
GO TO
CHECK O
YES
Faulty pump
Fan Check
Is fan connector
secure on the PCB (X4)?
NO
Secure Connector
YES
Is mains present at the
fan connector
(X4 pins 1 & 2)?
NO
GO TO
CHECK L
YES
Mains at fan
NO
Faulty Harness
YES
Faulty fan
29
NO
Ensure appliance is
cool and retest
Thermistor Check
Remove connectors
from thermistor
YES
Is resistance between
terminals of thermistor
between 690ohms & 33k?
NO
Faulty thermistor
YES
Thermistor OK
Harness Continuity Check
Remove appropriate
connectors
YES
Is continuity observed
between each end of
wire in question?
NO
Faulty harness
or connector
YES
Harness OK
Harness Short Check
Remove appropriate
connectors
YES
Is short circuit
observed between pair
of wires in question?
NO
Faulty harness
YES
Harness OK
30
Ignition Check
Is fan running?
NO
GO TO
CHECK G
NO
GO TO
CHECK E
NO
Is sparking present at
the electrodes?
YES
Does sparking occur?
GO TO
CHECK L
Faulty PCB
Replace
YES
Does ignition occur?
NO
YES
YES
Are ignition leads
connected both
ends securely?
Are leads breaking
down?
YES
Replace leads
NO
YES
Is flame sense
electrode in flame?
NO
Ensure flame sense
electrode in flame at
minimum burner
pressure
YES
Is lead secure
both ends?
NO
YES
GO TO
CHECK I
HARNESS OK
Faulty PCB
Replace
Does gas pressure
modulate?
NO
Connect ignition leads
securely
NO
Ignition coil faulty
replace PCB
YES
GO TO
CHECK M
Does burner continue?
NO
GO TO
CHECK N
YES
Ignition OK
31
Secure lead
L
Air Pressure Switch Check
Remove BROWN and
WHITE terminals
from air pressure
switch
With no demand, is a
short-circuit observed
at exposed APS
terminals?
NO
Air pressure switch
faulty
YES
Reconnect the
WHITE & BROWN
wire and remove the
GREEN wire. Initiate
a demand.
Does the fan run?
NO
YES
Fan or fan cable
faulty
YES
With fan running
disconnect BROWN
wire. (DO NOT touch
chassis with it). Is a
short circuit observed
across exposed APS
terminals?
Is there mains 230V
at fan connector X4
pins 1 and 3?
NO
Air pressure switch
faulty
YES
APS OK
Gas Valve Check
Is gas pressure present
at input to gas valve?
NO
Ensure gas supply
YES
Is live output present at
X5 pins 1 & 2 relative to
neutral at pin 3?
NO
Faulty board
Replace
NO
Faulty gas valve
Replace
YES
Is gas pressure present
at input to burner?
YES
Gas valve OK
32
NO
PCB faulty
N
Modulating Valve Check
Is minimum pressure
observed at burner at all
times?
YES
Remove X6, measure
resistance between
pins 15 & 16
NO
GO TO
CHECK I
NO
Is resistance
nominally 125ohms?
YES
Is pressure at burner
always the same?
YES
NO
With pressure above
minimum, remove Modureg
Lead. Does pressure drop to
minimum?
NO
Faulty modulating valve .
Replace gas valve
Reconnect X6 and measure
voltage across modulating
valve during operation
YES
Gas valve OK
YES
Does voltage
go above 6.25V?
NO
Faulty PCB.
Replace
Flow Switch Check
Remove X6
Close all taps to set no
domestic flow
Is open circuit observed
at X6 pins 1 & 2?
NO
Faulty flow switch.
Replace
NO
GO TO
CHECK I
YES
Open a tap fully to set
domestic flow
Is short circuit observed
at X6 pins 1 & 2?
YES
Flow Switch OK
33
HARNESS OK
Faulty flow switch.
Replace
19. Component Parts List
Key
No.
1
G.C. No.
E01-579
E01-580
2
E01-591
E00-741
3
E01-892
E01-893
4
E01-596
5
375 697
6
E01-612
E01-930
7
E01-598
8
E01-599
9
E01-600
10
E01-601
11
299-506
12
375 699
13
E01-602
14
E01-603
15
E01-604
16
E04-582
E01-900
299-495
18
E01-605
19
324-822
20
299-363
21
E01-606
22
E01-607
23
E01-886
24
299-357
25
E01-610
ACCESSORIES
299-360
E01-940
E01-941
E05-341
FLUE OPTIONS
E01-942
E01-943
E01-944
E01-945
E01-946
E01-058
E01-059
Part
Manufacturer’s Reference
Aeromatic
AC23/053586
Aeromatic
AC23/053587
Stereomatic O 4.3mm
Stereomatic O 2.78mm
SIT
SIT
Huba 605.99484
Buccleuch
Buccleuch
Qty
WHS
Part No.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
8 716 142 604 0
8 716 142 611 0
8 716 105
140 033
224 0
8 716 140 209 0
8 716 142 413 0
8 716 142 430 0
8 716 142 414 0
8 716 142 100 0
8 716 120 345 0
8 716 120 126 0
8 716 120 236 0
8 716 142 905 0
7 716 192 216 0
8 716 140 504 0
8 716 142 300 0
8 716 142 404 0
8 716 143 107 0
8 716 142 502 0
8 716 146 300 0
8 716 142 384 0
8 716 148 313 0
8 716 148 303 0
8 716 141 052 0
8 716 148 401 0
8 716 141 000 0
8 716 120 993 0
8 716 142 307 0
8 716 120 971 0
7 716 192 206 0
7 716 192 218 0
Burner Assembly Natural Gas
Burner Assembly LPG
Injector Natural Gas
Injector LPG
Gas Valve Natural Gas
Gas Valve LPG
Air Pressure Switch
Spark Electrode Assembly
Flame Sensor
Flame Sensor Harness
Ignition Harness
Gas to Water Heat Exchanger
Insulation Pack
Auto Air Vent
Pressure Gauge
Pressure Relief Valve
Pump with Harness
Expansion Vessel (8Ltr) 389mm Dia
PCB Boiler Control
Temperature Thermistors
CH Thermistor Clip
DHW Thermistor Clip
DHW Flow Regulator
Gauze Filter
Flow Sensor
Fan Assembly
Safety Temperature Limiter
Flow Switch Assembly
Fuse Pack
Gasket Pack
Buccleuch
Giannoni
Giannonni
WHS
Intermes
Cewal
Caleffi 3141 3bar
Grundfos 15 60 special
Winkelman Panhof
Pactrol
Elmwood
Mechanical Programmer Kit
Gas Conversion Kit
Gas Conversion Kit
Mini Expansion Vessel Kit
DIEHL
Deihl
NG to LPG
LPG to NG
Including new pipe and Expansion Vessel
7 716 192 002 0
7 716 192 131 0
7 716 192 132 0
7 716 192 188 0
Telescopic Horizontal Flue Kit
Extension Flue Kit
Vertical Flue Kit
Vertical Flue Adaptor
Internal Fixing Kit
Flue Elbow Kit
Flue Elbow Kit
425
- 725mm
127-350
mm
716 191
191068
005 0
7 716
WHS
WHS
SIFAN
Ranco LM7
SIKA
WHS
WHS
750 mm
7 716 191 006 0
7 716
716 191
191069
015 0
Telescopic Flue
90 deg.
45 deg.
34
7 716 191 016 0
7 716 191 019 0
7 716 191 013 0
7 716 191 014 0
9
8
14
3
21
1
15
22
4
13
12
7
11
10
20
23
23
25
24
2
35
6
19
18
16
This manual is to be used in conjunction
with the variant part number of the bar
code below:
Worcester Heat Systems Limited (Bosch Group), Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: (01905) 754624. Fax: (01905) 754619.
Technical Helpline 08705 266241.
www.worcester-bosch.co.uk
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 8 716 115 050a (05/08)
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertising