Bosch WORCESTER HEATSLAVE 12/14 User manual

HEATSLAVE
12/14, 15/19, 20/25, 26/32
FLOOR-STANDING OIL-FIRED COMBINATION BOILERS FOR
CENTRAL HEATING AND MAINS-FED DOMESTIC HOT WATER
USER INSTRUCTIONS &
CUSTOMER CARE GUIDE

EXCELLENCE COMES
AS STANDARD
Thank you for purchasing a Danesmoor oil-fired central
heating boiler.
Heatslave oil boilers are made by Worcester Heat Systems and
the strictest quality control standards ever demanded are applied
throughout every stage of production.
Indeed, Worcester Heat Systems have led the field in
innovative boiler design and
performance for more than 30
years.
The result is that your
new Heatslave boiler offers you
the very best of everything –
quality, efficiency, economical
running costs, proven
reliability and value for money.
What’s more, you also
have the assurance of our no-
nonsense 2 year parts and
labour guarantee.
And it’s backed up by
Worcester Care Call – a
complete maintenance scheme to keep your boiler operating at
peak condition and efficiency.
No wonder that more and more people are agreeing that when
it has to be oil, it has to be Heatslave.
Page No.
General Information ....... 3
Your Heatslave system
controls........................... 5
How to operate your
boiler............................... 8
Fault Finding Guide .... 12
Maintenance and
Extended Warranty ..... 13
The Heatslave
Guarantee ..................... 15
CONTENTS
2

GENERAL
INFORMATION
To ensure you get the very best from your new Worcester
Heatslave oil boiler, please read these notes and instructions
carefully.
The Worcester Heatslave is a combination boiler which
provides mains-fed domestic hot water and full central heating. It
utilises a Heatslave tank and a heat exchanger, which ensure that
whenever a tap is turned on there is an instantaneous output of hot
water.
The boilers control system gives priority to the domestic hot
water supply. This means that during hot water draw-off and
Heatslave tank recovery periods, the total output of the boiler is
directed to the Heatslave tank. If the central heating is switched on
during this period, the circulation of hot water to the radiators will
be temporarily interrupted but will resume as soon as the Heatslave
tank has been recharged to the temperature set on the hot water
control thermostat.
SERIAL NUMBER
Your boiler serial number and model number should always
be quoted in any contact with Worcester Heat Systems. This will
help identify spare parts and also avoid confusion and delays
during any service call-out. You will find these numbers on a label
on top of the electrical control box cover plate, and access can be
gained by removing the top panel of the boiler casing.
FUEL
Your Worcester Heatslave pressure jet boiler is set to burn 28-
second kerosene fuel. Some models can be converted to burn 35-
second gas oil. If this conversion has been made your installer will
inform you.
PLEASE NOTE: Appliances fitted with a low-level discharge
flue MUST NOT be used with 35-second gas oil.
OPEN-FLUED BOILERS
Your installer will create airways (in walls or doors) to ensure
an adequate supply of fresh air to the boiler for combustion. Do not
block these airways, and never hang clothes or other combustible
materials over the boiler or against the flue pipe.
Never place anything on top of the boiler.
3

4
ROOM-SEALED BALANCED FLUE
BOILERS
Air for this type of boiler is supplied via the balanced flue
terminal, and no other air supply is required, except for ventilation
if the boiler is installed in a cupboard or compartment.
ELECTRICAL SUPPLY
The mains supply for your Heatslave boiler is 230/240 volts
AC-50Hz. The internal fuse is a 3- amp, 20mm quick-blow fuse.
ELECTRICAL CONNECTION
A mains cable should be connected to a double pole isolator
with a contact separation of 3 mm on all poles and supplying the
appliance and controls only.
Your boiler must be earthed and protected by a 5-amp fuse.
ROUTINE MAINTENANCE
It is essential that your boiler is installed and serviced by a
competent heating engineer, and Worcester Heat Systems will be
pleased to arrange regular servicing and a comprehensive
maintenance contract.
Alternatively, the Oil Firing Technical Association for the
petroleum industry (OFTEC) will gladly advise you of engineers
trained by and registered with OFTEC.
Servicing should be carried out at least once a year for boilers
which burn 28-second kerosene, and twice a year for boilers which
burn 35-second gas oil.
When considering additional controls or fittings for your new
Heatslave hot water and central heating system, please note the
following:
ROOM THERMOSTAT
It is recommended that a mains voltage room thermostat is
fitted, as this will improve your control of room temperatures.
THERMOSTATIC RADIATOR VALVES
Any thermostatic radiator valves fitted to your central heating
system must conform to BS 2767/10.
ADDITIONAL FITTINGS
& CONTROLS

5
SHOWERS, BIDETS, TAPS AND MIXERS
Any taps and mixers used with your system must be suitable
for operating at mains pressure.
For a shower it is recommended that you fit a
thermostatically-controlled shower valve, as this will give added
safety by protecting against excessive water temperatures.
Mains-fed hot and cold water can be supplied direct to an
over-rim flushing bidet, subject to local water bye laws.
If a loose shower head with a flexible hose is to be used over
the bath, the hose must be fixed so that the head cannot fall closer
than 25mm (1 inch) above the top edge of the bath, so preventing
its immersion in bath water. Alternatively, the shower must
incorporate or be fitted with an anti-syphonage device at the point
of the flexible hose connections.
HOT AND COLD FLOW
The flow of water from your hot and cold taps depends on the
mains water pressure, and in some homes it might not be possible
to operate several taps simultaneously. To ensure an even
distribution of water to all outlets in the home, you can fit
individual flow regulators to the supply pipes.
USER OPERATING SWITCH
Your boiler facia panel is supplied with a user operating
switch as standard, although this may have been replaced with the
optional facia mounted electronic programmer or a remote
programmer.
If ‘HOT WATER’ only is selected
The boiler will keep the Heatslave tank at the temperature set
on the hot water control thermostat.
Whenever a tap or shower is turned on, the burner will ignite
and water will be pumped through the water to water heat
exchanger to provide hot water.
YOUR HEATSLAVE
SYSTEM CONTROLS

6
Your installer will
have provided adequate
space around the appliance
for safety and servicing. Do
not restrict this space by
the addition of cupboards,
shelves etc. close to the
appliance.
Minimum clearances in millimetres.
NOTE: If the appliance is to be enclosed after the
installation then the instructions given in Section 6, Air
Supply, of the Installation Book MUST be followed.
ROOM THERMOSTAT
A room thermostat may be fitted for control of the central heating
temperature. It will be located in one room of the home. The method
of setting a room thermostat varies with the type and manufacture.
Refer to the instructions supplied with the room thermostat.
THERMOSTATIC RADIATOR VALVES
If thermostatic radiator valves are to be fitted to the system then
they must conform to the requirements of BS2767:1972. It is advisable
to leave one valve permanently set at maximum to prevent the boiler
short cycling.
SHOWERS, BIDETS, TAPS AND MIXING
VALVES
Standard hot and cold taps and mixing valves used with the
appliance must be suitable for operating at mains pressure.
Thermostatically controlled shower valves will guard against the flow
of water at too high a temperature.
If using a pressure equalising valve, set the Domestic Hot Water
temperature control knob to the ‘MAX’ position.
Hot and cold mains fed water can be supplied direct to an
overrim 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.
For further information contact Worcester Heat Systems
Technical Helpline.
HOT AND COLD FLOW
If the flow of water demanded from both hot and cold service
outlets is dependent upon mains supply, it may not be possible in
some installations to operate all outlets simultaneously.
WATER MAINS FAILURE
It is important to note that in the event of a mains water supply
failure, no tap water will be available until the mains supply is
restored. The appliance can still be used for heating provided that the
system is of the sealed system type.
RSF
Left-hand side 10
Right-hand side 10
In Front 600
Above the casing 180
Below 200
CLEARANCES

7
EXTERNAL PROGRAMMER
You may opt to have a programmer sited away from the
boiler, in which case your installer will provide setting and
operating instructions.
CENTRAL HEATING TEMPERATURE
CONTROL
The central heating temperature control knob on the boiler
facia panel enables you to control the temperature of the water in
your radiators. A low temperature is indicated by a single
horizontal bar, and the control knob can be set anywhere between
this and the maximum temperature, which is indicated by five
horizontal bars. (As shown in Fig. 1.)
PLEASE NOTE: The control knob must not be set below the
first indicating bar.
HOT WATER TEMPERATURE CONTROL
The hot water control temperature knob on the boiler facia
panel controls the temperature of the primary hot water stored in
the Heatslave tank. The temperature control settings are as for the
central heating control thermostat
(described above). A high setting will give
higher hot water temperatures and greater
quantities of hot water.
The temperature of your hot water
can also be controlled at the tap by varying
the flow rate; increasing the flow rate will
decrease the temperature, and vice versa.
WARNING. Care should be taken when
washing your hands as the combination of
low water flow rate and a high setting of
the hot water control thermostat can result
in very hot water at the tap.
The control knob has a range of adjustment as
indicated by the symbols.
Fig. 1.
TEMP
Low
Setting
High
Setting

8
INDICATION LIGHTS
There are two indicator lights on the facia panel — POWER ON
and LOCKOUT.
The POWER ON light shows that there is an electrical power
supply to the electrical control panel. This will remain on at all times
provided there is an external electrical supply and the internal fuse has
not blown.
The LOCKOUT light illuminates if a burner ignition failure
occurs. The burner can be reset after two minutes by pressing the
illuminated lockout reset button located on the burner control box.
PLEASE NOTE: Do not attempt to repeatedly restart the boiler
as persistent lockout indicates a fault and you should consult a service
engineer.
OVERHEAT THERMOSTAT
Your boiler is fitted with a manual reset overheat thermostat. If
the burner fails to operate and the LOCKOUT indicator light is not
illuminated, check the overheat thermostat by pressing the reset
button. The thermostat is located on the underside of the electrical
panel and is accessible by removing the boiler casing front panel. If
the problem continues after pressing the reset button, consult a
service engineer.
If your boiler is being operated for the very first time following
the installation your installer should have commissioned the system
as specified in the Installation Instructions.
HOW TO OPERATE YOUR
BOILER
Fig. 2. Control Facia
Domestic Hot Water Temperature
Control Knob
Overheat Thermostat
Reset Button
Lockout Indicator
Light
Central Heating Temperature
Control Knob
Mains Power Indicator
Light
Optional programmer
location

9
TO START YOUR BOILER
First ensure that the oil supply is turned on.
Now switch on the mains electricity and turn the hot water
and central heating temperature control knobs to maximum. Set
the user operating switch (or programmer) so that both HEATING
& HOT WATER ARE ON.
The burner should now ignite.
Set the user operating switch (or programmer) to suit your
own requirements, and if a room thermostat is fitted set the desired
temperature.
Similarly, set the hot water and central heating temperature
control knobs to the desired temperature level.
TO SWITCH YOUR BOILER OFF FOR
SHORT PERIODS
Set the programmer to OFF.
TO SWITCH YOUR BOILER OFF FOR
LONG PERIODS
Set the user operating switch (or programmer) to OFF and
switch off the mains electricity at the isolator switch. The facia-
mounted programmer (where fitted) will retain its settings for
about four weeks, after which it will revert to the factory-set
programme, but the display will disappear after approximately
twelve hours.
CENTRAL HEATING SYSTEM
OPERATION
During the first operation of the central heating system, check
that all radiators are heated evenly. If the top of a radiator is at a
lower temperature than the bottom, vent it by releasing air through
the vent screw at the top of each radiator. Your installer should
show you how to carry out this simple procedure, and give you the
special key required to do it.
Should you find any leaks in the system, or find that any
radiator requires excessive venting, ask the installer or a service
engineer to rectify the system.
SEALED SYSTEM OPERATION
If your boiler has been fitted to a sealed primary water system,
a minimum water operating pressure must be maintained. This
minimum pressure is indicated by the pre-set pointer located on
the pressure gauge, which can be viewed by removing the front
panel of the boiler casing.

10
If the pressure falls below this minimum level, the system
must be re-pressurised using the method described by your
installer.
To ensure that the boiler and system are full of water and
pressurised, check the pressure gauge indicator needle. Consult
your installer or service engineer if the system continues to lose
pressure, as this could indicate a leak.
MAINS SERVICE INTERRUPTIONS
In the event of mains water supply failure, no hot water will
be available from the boiler. However, the central heating system
will continue to operate.
If the electricity supply fails, the boiler will not operate. When
the supply is restored, the boiler will return to normal operation,
but you should check that the programmer has maintained your
required settings.
It is essential that your boiler is serviced by a competent
engineer, as previously described on page 4. These notes will also
be helpful in maintaining your boiler‘s efficiency and performance.
CLEANING
Use a damp cloth and a small amount of detergent to clean the
boiler casing. Never use abrasive cleaners.
FROST PRECAUTIONS
To protect your central heating system from freezing, your
installer may have fitted a mains voltage frost thermostat. If so,
your boiler should only be switched OFF at the user operating
switch (or programmer), otherwise the burner will not operate
when there is a demand via the frost thermostat.
If your boiler has not been fitted with a frost thermostat and is
not to be used during a long period of cold weather, the boiler and
the system should be drained to prevent freezing. If your boiler is
not to be used during short periods of cold weather, leave it on a
low temperature setting.
LOOKING AFTER YOUR
BOILER AND SYSTEM

11
FAULTS & BREAKDOWNS
Many calls made to Worcester Heat Systems to report boiler
faults or breakdowns prove to be false alarms, as there is often a
simple explanation for the apparent malfunction.
So, to help you save time and money - not to mention
frustration and inconvenience - a quick-reference fault finder is
included on page 12.
If, after checking through the points suggested, there is still a
fault, you should call your local Worcester Heat Systems Service
Centre. Arrangements will be made for an engineer to call as soon
as possible.
CALL-OUT CHARGES
All of Worcester Heat Systems’ field service engineers are
factory trained.
If you request a visit from an engineer and your boiler has been
installed within the last 24 months, no charge will be made for
parts and/or labour providing:
●The appliance was commissioned correctly on installation
and a completed Guarantee Registration Card returned to
Worcester Heat Systems.
●An appliance fault is found and the appliance has been
installed within the past 24 months, provided that the first
annual service has been carried out on a boiler which is more
than 12 months old. Reasonable evidence of this must
be supplied on request.
HARD-WATER AREAS
If you live in an area where the mains water is exceptionally
hard, it is recommended that an in-line scale inhibitor is used in
your boiler and system, in strict accordance with the requirements
of your local water company and bye laws. An isolating valve, to
facilitate servicing, should also be incorporated.
Water hardness can be determined by reference to your local
water company. Further information can be obtained from
Worcester Heat Systems.

12
SYMPTOM POSSIBLE CAUSE CHECK/REMEDY
Red ‘Power On’ There is no electricity supply • Power supply is switched on.
Indicator is not to the boiler. • Check the fuse has not blown.
illuminated. Boiler internal fuse has blown.
• Check Fuse F1 on boiler PCB Board.
‘Power On’ Indicator There is no demand
• Check boiler thermostat is set on
illuminated only. requiring the boiler to operate. medium to high.
• Check operating switch (or programmer)
is set for hot water and/or central heating
and re-set if necessary. (If programmer is
fitted see operating instructions).
• If the boiler is programmed for
central heating, check the room
thermostat is turned on.
Boiler overheat thermostat
• Check the pressure gauge indicator
has operated. needle and re-pressurise if necessary.
(See section “Sealed System Operation”.)
• Press overheat thermostat reset button.
(See section “Overheat Thermostat”.)
‘Power On’ & ‘Lockout’ The boiler has attempted • Check the level in your oil tank &
indicators both to ignite, but has gone to replenish if necessary.
illuminated. lockout. Remove the appliance front cover and
depress the lockout reset button on the
burner. (See section “Indication Lights”.)
FAULT FINDER
A call-out charge will be made where:
●The appliance has been installed for over 24 months
●The appliance has been installed for more than 1 year but less
than 2 years and has not had a first annual service by an
approved company.
OR
●Our Field Service Engineer finds no fault with the appliance
(see note).
OR
●The cause of breakdown is misuse or with other parts of your
plumbing/heating system, or with equipment not supplied by
Worcester.
NOTE: Invoices for attendance and/or repair work carried out
on your Worcester Heatslave boiler by any third party will not be
accepted.
If your boiler is not operating, it is suggested that you go through
the following simple checks before either calling your installer or
Worcester Heat Systems.

13
MAINTAINING YOUR
BOILER’S EFFICIENCY &
PERFORMANCE
Your new Worcester Heatslave oil-fired boiler represents a
long-term investment in a reliable, high quality product.
In order to realise its maximum working life, and to ensure it
continues to operate at peak efficiency and performance, it is
essential that your boiler receives regular, competent servicing and
annual maintenance checks beyond the initial 24 month guarantee
period.
Regular service contracts can be arranged with your installer –
however, if you have difficulty making a satisfactory arrangement
simply contact Worcester Heat Systems on
08457 256206 for help.
If you would like to know more about Worcester’s extended
warranty options please tick the appropriate box on your
Guarantee Registration Card.

14
SERVICE CENTRES
CONTACT NUMBERS:
UK Call Centre Tel. [phone]
UK Call Centre Fax. [phone]
Scotland only Fax. [phone]
OPERATING HOURS:
Mon - Fri 8.00am to 6.00pm
Sat 8.30am to 1.00pm
Please contact our UK Call Centre number where our friendly operators
will book your call with one of our team of nationwide engineers.
NOTE:
Sunday and Bank Holiday cover is not available
IMPORTANT
Do not touch or adjust any sealed component

15
YOUR WORCESTER
HEATSLAVE GUARANTEE
GUARANTEE
REGISTRATION
This appliance is guaranteed against faulty materials or
workmanship for a period of twenty four calendar months from the
date of installation subject to the following conditions and
exceptions.
1. That during the currency of this guarantee
any components of the unit which are
proved to be faulty or defective in
manufacture will be exchanged or repaired
free of material charges and free of labour
charges by Worcester Heat Systems
Limited.
2. That the householder may be asked to
prove the date of installation, that the
boiler was correctly commissioned and,
where appropriate, the first 12 month
service has been carried out to the
satisfaction of Worcester Heat Systems
Limited when requested.
3. That any product or part thereof returned
for servicing under the guarantee must be
accompanied by a claim stating the Model,
Serial Number, Date of Installation, proof
of commissioning, proof where
appropriate of the first 12 month service
and the address of the householder.
4. That Worcester Heat Systems Limited will
not accept responsibility for damage
caused by faulty installation, neglect,
misuse or accidental damage, the non-
observance of the instructions contained in
the installation and Operating Instructions
Leaflets.
5. That the appliance has been used only for
normal domestic purposes for which it was
designed.
6. That this guarantee applies only to
equipment purchased and used in Great
Britain and Northern Ireland.
You should complete and return the postpaid Guarantee
Registration Card within 14 days of purchase.
The card will register you as the owner of your new Worcester
Heatslave boiler and, while this will not affect your statutory rights
in any way, it will assist us to maintain an effective and efficient
customer service by establishing a reference and permanent record
for your boiler.
FOR YOUR OWN RECORD
MODEL SERIAL NUMBER
(See identity label inside appliance casing)
TYPE/SIZE DATE OF INSTALLATION
This guarantee is given in addition to all your normal statutory rights.

Worcester Heat Systems Limited. Cotswold Way, Warndon, Worcester WR4 9SW.
Telephone: [phone]. Fax: [phone].
Technical Service Helpline 08705 266241.
www.worcester-bosch.co.uk
8 716 101 859c 03/01