Bosch Worcester Greenstar Comfort II RF User manual

UK/IE
Installation and operating instructions
Radio Frequency Twin Channel Programmable Room Thermostat and Receiver
Greenstar Comfort II RF
select
advance
select
advance
menu
6720810965-00.1Wo
For EMS compatible Worcester Greenstar condensing boilers
6720810965 (2017/02)

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Contents
Comfort II– 6720810965 (2017/02)
Contents
1 Key to symbols and safety instructions . . . . . . . . . . . 3
1.1 Key to symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 General safety instructions . . . . . . . . . . . . . . . . . . 3
2 Comfort II RF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Programmable room thermostat . . . . . . . . . . . . . 4
2.2 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 Comfort II RF installation . . . . . . . . . . . . . . . . . . . . . . . 5
3.1 Receiver mounting . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2 Programmable room thermostat mounting . . . . . 6
3.3 Date and time set up . . . . . . . . . . . . . . . . . . . . . . . 8
4 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1 Normal operation . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2 Programmable room thermostat . . . . . . . . . . . . . 8
4.2.1 Room temperature indication in Auto mode . . . 9
4.2.2 Room temperature indication in the On mode . 9
4.2.3 Room temperature indication in the Off mode . 9
4.2.4 Setting a new room temperature . . . . . . . . . . . . 9
5 Programmable room thermostat settings . . . . . . . . 10
5.1 User . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1.1 Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1.2 HW (Hot water) . . . . . . . . . . . . . . . . . . . . . . . . 11
5.1.3 Holiday function . . . . . . . . . . . . . . . . . . . . . . . 11
5.1.4 Info . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.1.5 Setting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2 Installer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.2.1 System data . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.2 Reset all . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.3 Heat circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.4 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.2.5 System info . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2.6 Radio settings - Pair/Unpair . . . . . . . . . . . . . . . 15
5.3 Key lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6 Receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.1 Override push button . . . . . . . . . . . . . . . . . . . . . 15
6.2 Pairing/Unpairing . . . . . . . . . . . . . . . . . . . . . . . . 15
7 Fault finding and resolution . . . . . . . . . . . . . . . . . . . 16
7.1 Fault table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
7.2 Unit replacement - single zone heating, or multi-
zone heating utilising a Greenstar wiring centre 17
7.2.1 Unpair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7.2.2 Pair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
8 Servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
9.1 Programmable room thermostat battery
replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
10 ErP Class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
11 Environment / disposal . . . . . . . . . . . . . . . . . . . . . . . 19
IMPORTANT
THE UNITS ARE PRE-COMMISSIONED,
NO RF PAIRING IS REQUIRED PRIOR TO USE
REPLACEMENT UNITS OR FOR MULTIPLE ZONE
HEATING (WITH GREENSTAR WIRING
CENTRE)WILL REQUIRE PAIRING,
PLEASE REFER TO SECTION 7.2

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Key to symbols and safety instructions
Comfort II– 6720810965 (2017/02)
1 Key to symbols and safety instructions
1.1 Key to symbols
Warnings
The following keywords are defined and can be used in this
document:
•NOTICE indicates a situation that could resultin damage to
property or equipment.
•CAUTION indicates a situation that could result in minor to
medium injury.
•WARNING indicates a situation that could result in severe
injury or death.
•DANGER indicates a situation that will result in severe
injury or death.
Important information
Additional symbols
Abbreviations
Definitions (DST/BST)
Daylight Saving Time (DST) and British Summer Time (BST)
begins on the last Sunday in March at 1:00am GMT and clocks
are put forward by one hour.
British Summer Time (BST) ends on the last Sunday in October
at 2:00am BST and the clocks are put back by one hour.
1.2 General safety instructions
These installation instructions are intended for heating
engineers, and electricians.
▶ Read any installation instructions (boiler, heating controls,
etc.) carefully before starting the installation.
▶ Observe the safety instructions and warnings.
▶ Observe national and regional regulations, technical rules
and guidelines.
▶ Record all work carried out.
Appliance operation
This appliance can be used by children aged from 8 years and
above and persons with reduced physical, sensory or mental
capabilities or lack of experience and knowledge if they have
been given supervision or instruction concerning use of the
appliance in a safe way and understand the hazards involved.
Children shall not play with the appliance. Cleaning and user
maintenance shall not be made by children without
supervision. (BS EN 60335-1 2012)
Installation, commissioning and servicing
Installation, commissioning and servicing must only be carried
out by a competent engineer.
▶ Only use original spares.
Electrical work
Electrical work must only be carried out by a qualified
electrician.
▶ Before starting electrical work:
– Isolate the mains electrical supply and secure against
unintentional re-connection.
–Checkforzerovoltage.
▶ Also observe connection diagrams of other system
components.
Handover to the user
When handing over, instruct the user how to operate the
heating system and inform him about its operating conditions.
▶ Explain how to operate the heating system and draw the
user's attention to any safety-relevant action.
▶ Explain that modifications and repairs must only be carried
out by an authorised contractor.
▶ Advise the user to have the system serviced annually by a
competent engineer.
▶ Leave the this instruction manual with the user or at the
appliance.
Warnings in this document are identified by a
warning triangle printed against a grey
background.
Keywords at the start of a warning indicate the
type and seriousness of the ensuing risk if
measures to prevent the risk are not taken.
This symbol indicates important information
where there is no risk to people or property.
Symbol Explanation
▶ Step in an action sequence
Cross-reference to another part of the document
• List entry
– List entry (second level)
CH = Central Heating
DHW = Domestic Hot Water
RF = Radio Frequency
DST = Daylight Savings Time
BST = British Summer Time
GMT = Greenwich mean time
RPB = Rotary Push Button

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Comfort II RF
Comfort II– 6720810965 (2017/02)
2ComfortIIRF
The Comfort II RF comprises a wall mounted twin channel RF programmable room thermostat and a boiler or wall mounted RF
receiver.
2.1 Programmable room thermostat
The wall mounted unit is a twin channel RF Programmable room thermostat. The Programmable room thermostat is for central
heating and hot water control with modulating/enhanced load compensating boiler regulation. Up to six time and temperature
periods can be set to control central heating as well as up to three ON and Off times to control hot water.
This enhance load compensating function enables an intelligent conversation with the boiler to achieve the desired room
temperature in the most efficient way possible. To help save the customer money by burning less fuel, and to minimise room
temperature “overshoot” the boilers burner may stop firing just prior to the desired room temperature being reached. This
behaviour including reduced radiator temperature is perfectly normal. The customer should simply set a temperature on the
thermostat that they are comfortable with and allow the room thermostat and boiler to do their work.
All programming and adjustment is conveniently done from the Programmable room thermostat making the Comfort II RF an
excellent solution if your boiler is not easily accessible.
The unit has user and installer menus to allow the setting of the temperatures, time programs, monitoring of system information,
setting current time/date, daylight savings, maintenance schedules, and pairing the device with the Receiver.
Fig. 1 Programmable room thermostat
1Display Temperature, time, date, CH and HW program selection, fault codes, menu
symbols and operational symbols
2 Hot water program selection ON, OFF, AUTO, ONCE, NA (NA displayed on additional Room stats in multiple
CH zone applications)
3 Hot water (HW) program advance button /
user menu selection button
Only functional in AUTO mode. Pressed once, advances the timer to the next
programmed ON or OFF time, pressed again, returns to the current program.
Hold the button down for more than 3 seconds to enter the user menu program
4 Rotary push button knob Turn or press to select or confirm settings
5 Central heating program advance button /
Return button
Only functional in AUTO mode. Pressed once, advances the timer to the next
programmed ON or OFF time, pressed again, returns to the current program.
When in the menu functions this button return to next higher level
6 Cental heating program selection ON, OFF, AUTO
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Comfort II RF installation
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2.2 Receiver
This unit is only used in conjunction with the Programmable
room thermostat.
The unit can be mounted in the boiler fascia, refer to your boiler
Installation, Commissioning and Servicing instruction manual
for fitting instructions.
The unit can also be wall mounted and hard-wired to the boiler
via the EMS BUS connections.
Fig. 2
[1] Fault indicator/Pairing indicator
[2] Override button/Pairing button
3 Comfort II RF installation
Refer to the boiler’s Installation, Commissioning and Servicing
instruction manual for information on the boiler.
Refer to this manual for detailed information on installing and
using the Comfort II RF.
A brief overview of the Comfort II RF installation procedure is
listed below:
▶ Isolate the boiler
▶ Remove any panels or casings required to gain access to
the control panel
▶ Mount the Receiver (boiler fascia or a suitable wall location
using the optional Wall Mounting Plate Kit, this will require
wiring between the boiler EMS BUS connections and Wall
Mounting Plate)
▶Turntheboileron
▶ Insert batteries in the Programmable Room thermostat
▶ Set time and date on the Programmable room thermostat
▶ The units will automatically connect to each other
▶ Ensure that the signal strength is adequate at the
Programmable room thermostat before mounting in a
suitable reference room Section 5.1.4 Info - Signal
strength on page 12
The Comfort II RF Programmable room thermostat consists of
two units: the Receiver that mounts into the boiler fascia or,
with an optional wall mounting kit, onto the wall and the
Programmable room thermostat which mounts on a wall in a
suitable reference room
3.1 Receiver mounting
There are two methods of mounting the Receiver:
• In the boiler fascia
• On the wall (optional wall mounting kit 7 733 600 039)
If your boiler is mounted remotely i.e. in the loft or an
outbuilding, you may want the Receiver to be conveniently
located for easy access
Boiler fascia mounted
Refer to your boiler’s Installation, Commissioning and Serving
instruction manual for mounting the Receiver into the boiler
fascia.
Wall mounted
Choose a convenient wall location, approximately 1.2 metres
from the floor, to mount the Timer.
The Receiver is a radio frequency (RF) device and as such is
flexible for positioning.
EMS connection
Run a two core cable from the boiler to the Receiver location.
Use an electrical cable with a minimum rating of H05VV-F.
For cable runs up to:
▶ 100 metres, use 0.50mm2conductor cross sectional area
▶ 300 metres, use 1.5mm2conductor cross sectional area
Connect the cable to the EMS bus point connections on the
boiler control circuit board, refer to the Installation,
Commissioning and Servicing instruction manual for your
boiler to locate the EMS connections.
CAUTION: Mains supplies
▶ Isolate the mains supplies to the boiler
before starting any work, and follow all
relevant safety precautions
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NOTICE: EMS Connections
▶The Programmer must NOT be
connected to the boiler’s 230 volt
supply or an external 230 volt supply.
▶ Ensure that the EMS cable is at least
100mm away from any power cables to
eliminate any mains interference
▶ EMS connections are not polarity sensitive

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Comfort II RF installation
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Optional wall mounting kit
Using the wall plate as a template, mark the position of the
mounting screws.
The optional wall mounting kit contains:
• 2 x countersunk screws
• 2 x plastic wall plugs
• Wall plate
•Topretainer
▶ Drill two holes to suit the size and depth of the wall plugs
▶Fitthewallplugs
▶ Feed the two core cable through the back of the wall plate
▶ Fit the wall plate [1],ensuring that it is level and tighten the
screws to secure
▶ Connect the two core cable to the terminal block, one core
to each outer connection, ignore the middle connection
Fig. 3 Receiver wall plate mounting
▶ Engage the four clips on the back of the Receiver [2] with
the four slots on the wall plate as shown in figure 4
▶ Push the Receiver down into the body of the wall plate to
secure
▶ Engage the tabs on the top retainer [3] into the slots on the
wall plate [1] and push down onto the Receiver to secure
Fig. 4 Fitting the Receiver to wall plate assembly
3.2 Programmable room thermostat mounting
Fitting the batteries
▶ Insert the batteries ensuring that the positive +end of the
battery is inserted into the positive + terminal of the holder.
Fig. 5 Fitting the batteries
▶ Fit the thermostat to the wall plate, locating the catches [1]
on the top edge and then snap the bottom edge into place
The Comfort II RF connects to your boiler’s EMS
BUS connections only, on an edge connector
identified either with BBor .
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Before mounting the Room thermostat wall
plate, fit batteries in the Room thermostat unit
and turn the boiler on to identify a location that
offers good RF signal.
Ensure that the batteries are the correct type
(LR6/AA) and oriented as shown in figure 5
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3
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Comfort II RF installation
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Room Thermostat positioning
Before mounting the room Programmable room thermostat on
the wall, it is good practice to find a position that affords good
signal strength.
Signal strength
▶Pressthemenu button for more than three seconds.
▶ Turn the knob to select Info and press the knob.
▶ Turn the knob to select Signal strength and press the knob
to enter the function.
The signal strength is displayed as a number from 0 to 10 in the
area where the temperature is normally displayed.
If the signal strength is low, try another position in that room
until the best possible signal strength is obtained.
Wall mounting plate
To remove the wall mounting plate:
1. Insert a suitable flat bladed screwdriver into the slot on the
bottom edge of the thermostat
2. Twist the screwdriver gently release the bottom catch.
3. Remove the wall plate from the programmable room
thermostat.
Fig. 6 Remove back plate
Wall mounting
The Programmable room thermostat is a radio frequency
device and as such is flexible for positioning, there is no
requirement to hard wire the device.
The thermostat requires free air flow and should be mounted in
an open area and not obscured by curtains or furniture. The
thermostat should be mounted no closer than 300mm to metal
objects, including metal wall boxes.
Mount the thermostat on a wall that is not subject to direct
sunlight or draughts, preferably on an inside wall at 1.2 metres
above the floor.
The thermostat must not be directly influenced by radiators or
other appliances giving off heat, such as televisions or lamps.
Fig. 7 Device location
Using the wall plate as a template, mark the position of the
mounting screws. The wall mounting kit provided with the
Programmable room thermostat contains:
• 2 x countersunk screws
• 2 x plastic wall plugs
▶ Drill two holes to suit the size and depth of the wall plugs
▶ Fit the wall plugs
▶ Fit the screws, but leave a sufficient amount proud to allow
the wall plate to be fitted over the screw heads
▶ Fit the wall plate, ensuring that it is level and tighten the
screws to secure
Fig. 8 Wall plate mounting
0=no signal
1 - 3 = weak signal
4 - 6 = acceptable signal
7 - 10 = very good signal
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1.
≥ 1000
≥ 1200
750
600
°C
°F
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Operation
Comfort II– 6720810965 (2017/02)
3.3 Date and time set up
4Operation
The Programmable room thermostat is supplied with factory
set default CH times and temperature periods and DHW ON and
OFF times that are shown in the table below. These settings can
be reset according to the homeowner’s requirements via the
User menu function on the Programmable room thermostat, 
section 5.1. The times and temperatures can be reset to the
factory setting via the User menu section 5.1.5. Settings -
Reset all.
4.1 Normal operation
During normal operation the display shows:
• current room temperature
• the operational modes of the central heating and hot water
• the current time and day, with am or pm for the 12 hour
time format are displayed when the screen is back lit, but
are not displayed when the screen dims after 20 seconds of
inactivity
Low battery
A battery symbol indicates the batteries require replacing,
refer to section 9.1
Burner ON indicator
The symbol is shown when the boiler is firing and heating up,
there can be up to a six minute delay between the boiler
indication and the programmer display.
Low RF signal strength
The A21 fault code indicates no RF signal, refer to section 5.2
Installer/Radio settings and section 6.2 Pairing/
Unpairing. 5.2.6
4.2 Programmable room thermostat
During normal operation the display shows:
• the operational mode for the central heating, are either
ON, OFF, AUTO, or ADV press the Central heating select
button to choose either:
–ON = heating is permanently on
–OFF = heating is permanently off
–AUTO = programmed times and temperatures for
heating
• In the Auto mode, press the Advance button once to move
to the next on or off time, press for a second time to return
to the current programme
• the operational modes for the hot water, are either
ON, OFF, ONCE, AUTO or ADV, press the HW select
button to choose either:
–ON = hot water is permanently on
–OFF = hot water is permanently off
–ONCE = hot water is on from the first programmed on
time to the last programmed off time
–AUTO = programmed times for hot water
• In the Auto mode, press the Advance button once to move
to the next on or off time, press for a second time to return
to the current programme
• the current time and day,
• am or pm for the 12 hour time format
• Graphical indication of the current time/temperature
settings, the black markers indicate half hour time periods,
and the height of the markers gives an approximation of the
temperature setting. The flashing black marker indicates
the current time position in the programmed sequence.
Fig. 9 Display elements
A21 will be displayed at initial switch on until
the two units have established an RF
communication link
Set the current time and date
▶Holdthemenu button down for more than
3 seconds to enter the user menu, turn the
knob to select Settings and press to enter
▶ Refer to section 5.1.5 Settings - Time/
Date for setting the Time and Date, and
clock format
The Programmable room thermostat and
Receiver are delivered together and are
factory paired, they automatically connect
when the system is switched on. There is no
need to pair/unpair the units during
installation. In the unlikely event that signal
issues are suspected refer to section 5.1.4. DO
NOT PAIR/UNPAIR UNITS
06:30 08:30 16:30 22:30
CH 1st 2nd 3rd 4th
CH TEMP 20 °C 16 °C 21 °C 10 °C
DHW ON OFF ON OFF
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Operation
Comfort II– 6720810965 (2017/02)
1. Current room temperature
2. HW operational status
3. Current day
4. Current time
5. Burner ON - display when boiler is heating (can be up to 6
minutes delay)
6. Frost protection - displayed when boiler is set to OFF
7. am or pm indication when in the 12 hour clock format
8. Central heating operational status
9. Battery condition indicator
4.2.1 Room temperature indication in Auto mode
When the Programmable room thermostat is in the Auto mode,
pressing the knob once and releasing will display the current
desired room temperature setting, and also when the next
temperature increase time is scheduled. The example shown
below indicates that the room temperature is 15 °C until 16:30
(4:30pm).
Fig. 10 Heating
4.2.2 Room temperature indication in the On mode
When the Programmable room thermostat is in the On mode,
pressing the knob once and releasing will display
“Permanently” and the temperature that is permanently set.
Fig. 11 Permanently ON
4.2.3 Room temperature indication in the Off mode
When the Programmable room thermostat is in the Off mode,
pressing the knob once and releasing will display
“Permanently”and the temperature of 5 °C.
After three seconds the display will revert back to show the
actual room temperature and also the frost symbol indicating
that if the room temperature goes below 5 °C the boiler will
come on and maintain that temperature to prevent freezing.
Fig. 12 Permanently OFF
4.2.4 Setting a new room temperature
Under normal operation the display shows the current room
temperature.
When the Auto or On mode, turn the knob anti-clockwise to
decrease the temperature or clockwise to increase. The new
temperature setting will flash for three seconds.
The display will briefly show the new temperature up to the next
time period change.
Fig. 13 Set target temperature
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Programmable room thermostat settings
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5 Programmableroomthermostatsettings
There are two levels of settings:
1. User
2. Installer
5.1 User
Press the menu button for more than three seconds to enter the
User setting area of the Timer/programmer.
Five icons are shown across the top of the display:
1. Heating (CH)
2. Hot Water (HW)
3. Holiday
4. Info
5. Settings
Fig. 14 User menu
Turn the knob to select an icon, the icon is encircled to confirm
the selection, and press the knob to enter that section.
5.1.1 Heating
The top line of the display shows the words Time programs plus
flashing arrow heads at each end, this indicates that there are
more programs available:
1. Time programs
Time programs
Select Time programs with the knob, and press to enter.
Press the Return button at any time to return to the
previous higher level.
In the Time program you can set up to 6 time and temperature
periods for CH.
Using the knob you can select various combinations of days, for
example:
▶MontoFri
▶ Sat and Sun
▶ Monday,Tuesday,Wednesday,Thursday,Friday,Saturday
and Sunday
Whether you choose to set the same times for Monday to Friday
and different times for Saturday and Sunday or set times for
individual days the setting operation is the same.
▶ Select the desired day(s) using the knob
▶ Press the knob to select Time setting 1, this should be the
first on time in the morning
▶ The hours flash, turn the knob to select the hours setting
▶ Press the knob to confirm
▶ The minutes flash, turn the knob to select the minutes
▶ Press the knob to confirm
▶Temp. setting 1 flashes, this will be the temperature that is
comfortable for your home during the first time period
▶ Turn the knob to set the required temperature and press
the knob to confirm
▶Time setting 2 hours flash, this will be the time that you
want the temperature set lower, maybe while the house is
unoccupied
▶ Turn the knob to select the hours setting and press the
knob to confirm
▶ The minutes flash, turn the knob to select the minutes and
press the knob to confirm
▶ Press the knob to confirm
▶Temp. setting 2 flashes, this will be the temperature that is
set for the second time period, this should be the lowest
temperature you want the house to be at while unoccupied
▶ Turn the knob to set the required temperature and press
the knob to confirm
▶Time setting 3 hours flash, this will be the time that the
temperature is set to another value, maybe higher because
the house is occupied now for the afternoon/evening and
you would like your heating on
▶ Repeat the process to set the hours and minutes for Time
setting 3
▶Temp. setting 3 flashes, this will be the temperature that is
set for the third time period,this should be the temperature
that you want the house to be at during the afternoon/
evening when the house is occupied
▶ Repeat the process to set to set the required temperature
for Temp. setting 3
▶Time setting 4 hours flash, this will be the time that the
temperature is set to another value, maybe lower for the
night time period
The display will dim after 20 seconds of
inactivity and remain dimmed until a button
is pressed or the knob is turned/pressed.
After 60 seconds of inactivity the display
will return to normal operation.
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Programmable room thermostat settings
Comfort II– 6720810965 (2017/02)
▶ Repeat the process to set the hours and minutes for Time
setting 4
▶Temp. setting 4 flashes, this will be the temperature that is
set for the fourth time period, this should be the
temperature that you want the house to cool down to
during the night
▶ Repeat the process to set to set the required temperature
for Temp. setting 4
▶ If you require time and temperature settings, repeat the
whole process for the Time settings 5, 6 and Temp.
setting 5
If after setting the time periods 5 and 6 you decide that you no
longer require it and wish to disable it, follow these steps:
▶ In the Time program, cycle through time periods by just
pressing the knob to accept the time and temperature
setting until you reach time setting 5
▶ Turn the knob to set the flashing hours to 00
▶ Press to accept and the minutes flash
▶ Turn the knob clockwise to 00 and then the display
changes to just dashes and time period 5 is disabled
▶ Repeat this process for temperature setting 5 and time
setting 6
5.1.2 HW (Hot water)
The top line of the display shows the words Time programs plus
flashing arrow heads at each end, this indicates that there are
more programs:
1. Time programs
This Time program is used to set your required ON and OFF
times for the hot water. The Programmer has default time
settings as shown below:
Time programs
Select DHW programs with the knob, and press to enter.
In the DHW program you can select ON and OFF times for the
hot water heating, there are three ON and three OFF programs.
Using the knob you can select various combinations of days or
individual days:
▶MontoFri
▶ Sat and Sun
▶ Monday, Tuesday, Wednesday, Thursday, Friday, Saturday
and Sunday
Whether you choose to set the same times for Monday to Friday
and different times for Saturday and Sunday or set times for
individual days the setting operation is the same.
▶ Select the desired day(s) using the knob
▶Presstheknobtoselect the first DHW ON setting
▶ The hours flash
▶ Turn the knob to select the desired hours setting
▶Presstheknobtoconfirm
▶Theminutesflash
▶ Turn the knob to select the desired minutes
▶Presstheknobtoconfirm
▶ThefirstDHWOFF hours flash
▶ Turn the knob to select the desired hours setting
▶Presstheknobtoconfirm
▶Theminutesflash
▶ Turn the knob to select the desired minutes
▶Presstheknobtoconfirm
▶NowthesecondDHWON hours flash
▶ Repeat the process to set the hours and minutes for the
seconding DHW ON times
▶ Repeat the process for the second DHW OFF times
▶ Repeat the whole process for the third DHW ON and OFF
times, if required
If after setting the third DHW time period you decide that you
no longer require it and wish to disable it, follow these steps:
▶ In the Time program, cycle through DHW time periods 1
and 2 by just pressing the knob to accept the time setting
until you reach period 3
▶ Turn the knob to set the flashing hours to 00
▶ Press to accept and the minutes flash
▶ Turn the knob clockwise to 00 and then the display
changes to just dashes and period 3 is disabled
5.1.3 Holiday function
Turn the knob to select the Holiday function
▶Presstheknobtoenter the program and OFF is displayed
▶PresstheknobandOFF flashes
▶IfON is selected and the knob pressed, two day/months
selections are displayed and the first day of the holiday
period flashes
▶ Turn the knob to select the desired day
▶ Press the knob to confirm the month now flashes
▶ Turn the knob to select the desired month
▶Presstheknobtoconfirm
▶ Now the last day of the holiday period flashes
▶ Turn the knob to select the desired day
▶ Press the knob to confirm and the month now flashes
▶ Turn the knob to select the desired month
▶Presstheknobtoconfirm
▶Holiday will be displayed when the function is active
▶ Press the Return button to leave the program after setting.
If the Time settings 5 and 6 are not required,
at the end of Temp. setting 4 repeatedly press
the knob to cycle through the third period
without making any settings.
06:30 08:30 16:30 22:30
DHW ON OFF ON OFF
If the third DHW period is not required
repeatedly press the knob to cycle through the
third period without making any settings.

12
Programmable room thermostat settings
Comfort II– 6720810965 (2017/02)
When the Holiday function is set, via this program, the function
will become active at midnight of the day set and inactive at
midnight on the last day set.
During the holiday period the hot water and CH functions are
off and will return to normal operation at the end of the holiday
period. The Frost symbol is displayed, indicating that the boiler
is OFF but is protected when the temperature falls below 5 °C.
To cancel the holiday function:
▶ Press the menu key for more than three seconds to enter
user menus and select Holiday, ON will be displayed.
▶PresstheknobandON flashes, turn the knob to select OFF
▶ Press the knob to confirm OFF
▶ Press the return button to go back to the normal display
5.1.4 Info
Turn the knob to select Info and press the knob, two menus are
available:
1. DHW
2. Signal strength
DHW
1. Turn the knob to select DHW and press to enter. The
current temperature of the DHW is displayed:
a. Actual temp
▶ Press the Return button to go back to DHW
Signal strength
Turn the knob to select Signal strength and press the knob to
enter the function.
The signal strength is displayed as a number from 0 to 10 in the
area where the temperature is normally displayed.
5.1.5 Setting
▶ Turn the knob to select Settings and press to enter the
function. Three sub programs are displayed:
1. Language
2. Time/date
3. Format
4. Reset all
1. Language
This function allows you to choose the language used by the
Programmer, by default is set to English (EN).
▶ Turn the knob to select language, EN flashes, select either:
–EN(English)
–NL(Dutch)
–dE(German)
▶ Press the knob to confirm the desired language
2. Time/Date
This function allows the current time and date to be set, this
would be used on initial set up of the Programmer or if the time
and date were lost due to the boiler being switched off for an
extended period of time.
Turn the knob to select Time/date and press to enter the
function:
▶Presstheknobtoselect clock time
▶ Press the knob and the hours flash
▶Turntheknobtoselect the correct hour
▶ Press the knob to confirm the selection and minutes flash
▶ Turn the knob to select the correct minutes
▶ Press the knob to confirm the selection
▶ Turn the knob to display the date set up
▶ Press the knob to select the function, the day flashes
▶Turntheknobtoselect the correct day
▶ Press the knob to confirm the correct day and the month
flashes
▶ Turn the knob to select the correct month
▶ Press the knob to confirm and the year flashes
▶Turntheknobtoselect the correct year
▶ Press the knob to confirm to set the year
▶ Turn the knob to display the DST (Daylight savings time)
▶PresstheknobandON flashes
▶ Turn the knob to select ON or OFF
▶ Press the knob to confirm the selection
▶ Press the return button to go back to Time/date and
turn the knob to select Format
3. Format
Press the knob to enter the format function and the following
sub menus are available:
1. Date format
2. Time format
3. Sensor calib.
4. Contrast
Date format
This function allows you to change the way the date is
displayed, by default the format is DD.MM.YYYY. Once the date
and time have been set the date format can be set:
▶Turntheknobto select the Date format function
▶ Press the knob to show the date format flashing
▶ Turn the knob to select either:
▶ DD.MM.YYYY
▶ MM/DD/YYYY
▶ When the desired format for the date has been selected,
press the knob to confirm and wait a few seconds for the
display to return to Date format
0=no signal
1 - 3 = weak signal
4 - 6 = acceptable signal
7 - 10 = very good signal

13
Programmable room thermostat settings
Comfort II– 6720810965 (2017/02)
Time format
▶ Turn the knob to select Time format
▶ Press the knob and the time format is displayed flashing
▶ Turn the knob to select either:
–12hour
–24hour
▶ Press the knob to confirm once the choice has been made
▶ When the desired format has been selected, turn the knob
to display Sensor calib.
Sensor calib.
If it is suspected that the temperature display is off by a few
degrees and if there is a precision temperature gauge/meter
available, the display can be offset by ±5 °C to compensate.
The default value is 0.0 °C.
▶ Press the knob to enter the temperature offset function,
the offset value is displayed, by default it is 0.0 °C.
▶ Press the knob and the display flashes.
▶ Turn the knob to adjust the temperature offset, between
-3 and +3 °C.
▶ Press the knob to confirm the desired setting
▶ When the desired format has been selected, turn the knob
to display Contrast
Contrast
▶ Press the knob to select Contrast, this function allows you
to adjust the contrast of the screen, by default it is set to 10
▶ Press the knob to select Contrast
▶ The current contrast flashes
▶ Turn the knob to select from 0 to 20 the desired level of
contrast
▶ Press the knob to confirm
Press the return button at any time to return to the next higher
level, you can keep pressing the return button until you return
to the normal display.
4. Reset all
Turn the knob to select Reset all, this function will reset all the
Programmable Room thermostat user settings back to the
factory default settings.
Any customised ON /OFF times and temperatures for heating
or ON/OFF times for hot water or any other customised settings
will have to be re-entered.
Any default settings are described at the beginning of the
functional descriptions.
Turn the knob to select Reset all
▶ Press the knob and NO flashes
▶ If a reset is required turn the knob to select YES
▶ Press the knob to confirm
▶ Dashes progress across the screen until four are displayed
briefly, then the display reverts to just showing Reset all
The Programmable room thermostat will be reset to factory
default settings, as shown in the table below, any customised
times for heating or hot water will have to be re-entered.
5.2 Installer
These functions are only used by the installer/service engineer
and are useful during both installation of the Comfort II RF to
make adjustment to suit the heating system; during an annual
service/inspection, or to assist with fault finding.
Press the menu button and return button for more than three
seconds to enter the Installer setting area of the programmer.
Six icons are shown across the top of the display:
1. Heating (CH)
2. Hot Water (HW)
3. Holiday
4. Info
5. Settings
6. Installer setting
Selections 1 to 5 are the same as the Timer / programmer user
menu, section 5.1.
Turn the knob to select the Installer icon and press the
knob to enter the function.
Fig. 15 Installer menu
06:30 08:30 16:30 22:30
CH 1st 2nd 3rd 4th
CH TEMP 20 °C 16 °C 21 °C 10 °C
DHW ON OFF ON OFF
6720810965-17.1Wo
23456
1
pmam

14
Programmable room thermostat settings
Comfort II– 6720810965 (2017/02)
Installer settings menu options
1. System data
2. Reset all
3. Heat circuit
4. Maintenance
5. System info
6. Radio settings
The menu options are displayed on the top line with flashing left
and right arrows heads, indicating that there are other menu
options available. Turning the knob will select each option in
turn, eventually returning to the first option.
5.2.1 System data
▶ Turn the knob to select System data
▶ Press the knob to enter System data and HC assignment
is displayed
▶ The display shows the number 1or 2for the second heat
zone
▶ This indicates which heating zone the controller is assigned
to
▶ Press the Return button to go back to System data
5.2.2 Reset all
The Programmer Installer menus will be reset to factory default
settings, any default settings are described at the beginning of
the functional descriptions.
▶ Turn the knob to select Reset all
▶PresstheknobandNO flashes
▶ Turn the knob to select NO or YES
▶ Press the knob to confirm, if YES is chosen all menus within
the Installer menu are reset back to default settings, four
dashes progress across thedisplay until the reset has taken
place,
if NO is chosen, no reset takes place
5.2.3 Heat circuit
This function allows the Installer/Service engineer to set the
maximum flow temperature for the central heating circuit to
potentially increase the efficiency of the heating system, the
default value is 85 °C.
▶ Turn the knob to select Heat circuit
▶ Press the knob to display Max flow in °C
▶ Press the knob and the temperature flashes
▶ Turn the knob to set the desired temperature for your
system design requirements
▶ Press the knob to confirm
▶ Press the Return button to go back to Heat circuit
5.2.4 Maintenance
1. Fault history
–Boilerfaults
–Cont.faults
2. Landlord func.
– Maint. date
– Maint. contact
a. Fault history
▶PresstheknobandBoiler. faults is displayed.
Boiler faults are displayed here and at the boiler, the
Programmable Room thermostat may be located remotely
from the boiler, so viewing the boiler faults at the
Programmable Room thermostat may be useful
▶ Press the knob and the first of five faults is displayed with
the fault code and occurrence date. The fault screens can
be scrolled through using the knob. If no faults have
occurred, the text No fault will be displayed
▶ Press the Return button to go back to Boiler faults
▶TurntheknobandCont. faults is displayed
▶ Press the knob and the first of five faults is displayed with
the fault code and occurrence date. The fault screens can
be scrolled through using the knob. If no faults have
occurred, the text No fault will be displayed.
▶ Press the Return button to go back to Cont. faults
▶ Or press the Return button again to go back to Fault
History
▶Turntheknobtoselect Landlord func. or press the Return
button go back to Maintenance
b. Landlord func.
This function is for social housing landlords only and enables a
maintenance/annual service date to be set.
The maintenance reminder message “Maintenance” is
displayed 30 days before the set date.
Along with the Maintenance message a contact telephone
number will also be displayed.
The tenant should call this number to arrange a convenient date
with the landlord for the service.
If the maintenance reminder message is not cleared or reset to
a later date, by the service engineer, then 14 days after the
scheduled maintenance date the controller will limit the room
temperature set point to 18°C.
Landlords:
▶ Call the Worcester Bosch technical support
team for instructions of how to set the
Maintenance message or contact
telephone number.

15
Receiver
Comfort II– 6720810965 (2017/02)
5.2.5 System info
1. Turn the knob to select System info
2. Press the knob and Install date is displayed
3. Press the knob and the install date is displayed
4. Press the knob to return to Install date
5. Turn the knob to select SW controller
6. Press the knob to display the software controller version
7. Press the knob to return to SW controller
8. Press the return button to go back to System info
5.2.6 Radio settings - Pair/Unpair
5.3 Key lock
When the Key lock is active, no user interaction with the units
is possible, if a button is pressed or the knob turned/pressed
the word Key lock is displayed.
Key lock ON
To activate the Keylock:
▶ Hold down the CH Select button and the knob at the same
time for more than three seconds and the Keylock is active
Key lock OFF
To de-activate the Key lock:
▶ Hold down the CH Select button and knob at the same time
for more than 3 seconds and the Key lock is de-activated
6Receiver
The Receiver is paired with the Programmable room
thermostat and they communicate via an RF signal. The
Receiver unit has an Override/Pairing push button and a LED to
indicate various sates of operation.
6.1 Override push button
If the RF signal between the Receiver and the Programmable
room thermostat is lost the LED, on the Receiver, will flash once
a second, indicating a local error (not a boiler fault).
During this time, the override push button can be briefly
pressed once (less than 3 seconds) to override the
Programmable room thermostat and maintain the boiler
function for heating and hot water.
During override the LED will be on but will flash off briefly to
indicate an override situation.
Press the override push button again briefly, to cancel the
override feature.
6.2 Pairing/Unpairing
Fig. 16 Receiver
[1] LED (for flash codes refer to the table below)
[2] Override button/Pairing button
The Programmable room thermostat and
Receiver are delivered together and are
factory paired, they will automatically
connect when the system is switched on.
The Programmable room thermostat and
Receiver are delivered together and are
factory paired, they will automatically
connect when the system is switched on.
Green indicator LED Indicates the status:
Normal
operation
OFF No central heating zone is
calling for heat
ON One or more zones calling for
heat
Manual
override
Flashing off, for
¼ second over a 2
second period
Manual override is active
Pairing
modes
2 x ¼ second flashes
over 5 a sec. period
Pairing in operation
5 x ¼ second flashes
over 5 a sec. period
Unpairing in operation
Push
button
Press for >5 seconds
for pairing
Press for >10 sec. for
unpairing
Pairing or unpairing the
Receiver with the
Programmable room
thermostat(s)
Press once, briefly, for
override, press again
for no override
Manually switching the boiler
ON or OFF
Table 1 Receiver LED flash codes
6720810965-15.1Wo
1
2

16
Fault finding and resolution
Comfort II– 6720810965 (2017/02)
7 Fault finding and resolution
7.1 Fault table
If a fault code is displayed the user must first press the knob to return to the main display.
The last 5 control faults can be viewed in the Faults history (refer to 5.2.4 Maintenance).
If a fault appears that is not listed within the table it could be that a boiler fault has occurred.
The boilers Installation & servicing manual should then be consulted.
Fault
code Problem Description Resolution
The temperature
displayed on the
thermostat unit is
different than the room
temperature
Temperature offset setting is other than 0 Check the temperature offset setting on the
Programmable thermostat (Setting menu 
Format Sensor calib. refer to section 5.1.5)
and adjust as required.
Room to room temperature difference Consider differences between rooms due to
draughts, sunshine etc. Move Room thermostat to
a more suitable location if necessary.
The required room
temperature has not
been achieved
Airlock Bleed the radiators and vent the heating system.
Low system pressure Top up the system pressure via the filling link.
Time program / weather change Is the heating on for long enough.
Flow temperature Set a higher flow temperature.
Thermostat valve in reference room Operate the TRV to ensure that it does not stick
Fully open the TRV.
The room temperature is
higher than the set value
The Room thermostat is subject to
draught or energy loss
Move the Room thermostat to a more suitable
location (refer to section 3.2).
No flame symbol visible
on the Room thermostat
The actual temperature is close to the
target temperature. The control turns the
boiler off early to prevent overshoot.
Set the target temperature is at least 2 ºC above
the current displayed temperature. It takes up to 6
minutes for the flame to come on.
The flame symbol is not available with oil fired boiler controls.
Cannot select DHW mode
on the Room thermostat.
NA is displayed.
The Room thermostat is part of a multiple
heating zone system in combination with
the Greenstar Wiring Centre. Only the
primary Room thermostat (the first to be
paired with the Receiver) is controlling
the DHW mode.
Select the required DHW mode on the primary
Room thermostat.
A21/
A22
Loss of RF signal The Room thermostat unit is incorrectly
positioned
Check signal strength and reposition
Room thermostat for better signal.
Wire the Receiver to a wall plate if the boiler is in a
loft or garage.
Receiver or Room thermostat unit has no
power supply
Check that boiler has power and that Room
thermostat batteries are not running low (see
Blank display or low battery symbol).
A21 will be displayed at initial
switch on until the two units have
established an RF communication link
Allow up to 1 minute after power up for the units to
communicate.
A23 Room stat internal sensor
failure
Internal room temperature sensor out of
valid range
Replace RF Room thermostat.
A24 Remote RF unit has a
fault
Another room thermostat in the system
has a problem
Check other room thermostats within the system
for fault codes.

17
Fault finding and resolution
Comfort II– 6720810965 (2017/02)
7.2 Unit replacement - single zone heating, or multi-zone heating utilising a Greenstar wiring centre
7.2.1 Unpair
Set the Receiver to the unpairing mode:
▶Pressandholdoverride/pairing button until the LED
flashes 5 times in a 5 second period, press for
approximately 10 seconds. Not to be confused with the
flashing frequency of the pair mode
Set the Room Thermostat in unpairing mode
▶ Turn the knob to select the Installer icon and press
the knob to enter the function
▶ Select Radio settings and press the knob
▶ Select Pairing and press the knob
▶ Select Unpairing and press the knob
Wait until the action is completed
When the unpairing between the devices is completed, A28
appears on the Room thermostat display and the Receiver’s
LED flashes once per second. The action takes approximately
one minute.
7.2.2 Pair
Set the Receiver to the pairing mode:
▶Pressandholdoverride/pairing button until the LED
flashes twice in a 5 second period, press for more than 5
seconds but less than 10 seconds.
Set the Room Thermostat in pairing mode
▶ Turn the knob to select the Installer icon and press
the knob to enter the function
▶ Select Radio settings and press the knob
▶ Select Pairing and press the knob
▶ Select Pairing and press the knob
Wait until the action is completed
When the pairing between the devices is completed, HC
assignment 1 appears on the Room thermostat display.
The Receiver’s LED stops flashing, pairing is now complete.
Wait or press the knob to return to the main screen.
The action takes approximately one minute.
A25 Multiple pairing fault Displayed when no zone is available for
this room thermostat
Unpair units and pair back up using a different
zone setting for each room thermostat. Up to 3
zones can be set up.
A26 Multiple pairing fault Displayed when 2 or more Programmable
room thermostats are paired to the same
Receiver, each with the same zone
setting.
Unpair all units and pair back up using a different
zone setting for each room thermostat.
A27 Unable to communicate
with boiler's EMS bus
Boiler is EMS compatible but no
communication
Replace the Programmer/Receiver unit.
A28 Not paired Unit is not paired Unpair and pair all (see section 7.2).
Receiver LED flashing
once per second (1 Hz)
Not a boiler fault, possibly no RF
connection with the Programmable room
thermostat(s), at least one connection
has been lost
Check the Programmable Room thermostat(s) for
fault code (if none is displayed, turn the knob).
Blank display or low
battery symbol
Batteries are depleted Replace batteries and clean battery contacts.
Other
fault
Comfort II Room thermostat also displays
boiler fault codes.
Refer to the boiler’s Installation, Commissioning
and Servicing instruction manual.
Fault
code Problem Description Resolution
IMPORTANT
▶ Do not pair units twice as this will affect their function
▶ When replacing a unit, unpair the unit from the Receiver or Room thermostat, before pairing the new unit
▶ The Greenstar Wiring Centre (7 738 110 116) is required to connect additional Programmable Room
thermostats to the Receiver
Two Central heating zones requires a second
Programmable thermostat 8 716 117 239.
Follow the same pairing procedure as above,
when HC assignment 1 is displayed, change to
HC assignment 2

18
Servicing
Comfort II– 6720810965 (2017/02)
8Servicing
These units can not be serviced.
Should either unit fail to function correctly check that the:
▶ Programmable room thermostat settings are correct
▶ RF signal link between the units is set up correctly, 
sections 6.2 and page 15 Radio settings
▶ Programmable room thermostat batteries are the correct
type, fitted correctly and are not exhausted.If in doubt, fit
new batteries section 9.1.
9Maintenance
These units require no maintenance apart from replacing used
batteries in the programmable room thermostat.
The outer casing can be wiped clean using a dry cloth, do not
used polish or detergents.
9.1 Programmable room thermostat battery
replacement
If under normal operation the battery low symbol appears, the
batteries require replacing within 60 days or the programmed
settings will be lost.
Replace the batteries with the same type: LR6/AA 1.5V
alkaline.
Fig. 17 Low battery indication
Battery access
To remove the room thermostat from the wall mounting plate:
1. Insert a suitable flat bladed screwdriver into the slot on the
bottom edge of the device
2. Twist the screwdriver gently until the bottom catches are
released.
3. Separate the Programmable room thermostat from the its
wall plate.
Fig. 18 Remove back plate
Battery replacement
Replace the spent batteries with new ones of the same type
(AA), ensuring that they are installed in the correct orientation.
Insert the batteries ensuring that the positive +end of the
battery is inserted into the positive + terminal of the holder.
Fit the Programmable room thermostat to the wall plate,
locating the catches [1] on the top edge and then snap the
bottom edge into place.
Fig. 19 Replace batteries
6720810965-11.1Wo
1
pmam
6720810965-09.1Wo
2.
1.
6720810965-10.1Wo
+
+
1

19
ErP Class
Comfort II– 6720810965 (2017/02)
10 ErP Class
The data represented in the table below is required for the
completion of Energy Related Product (ErP) Directive System
Package fiche and, subsequently, the ErP system data label.
ERP Labelling obligation applicable from 26th September
2015.
11 Environment / disposal
Environmental protection is a fundamental corporate strategy
of the Bosch Group.
The quality of our products, their economy and environmental
safety are all of equal importance to us and all environmental
protection legislation and regulations are strictly observed.
We use the best possible technology and materials for
protecting the environment taking account of economic
considerations.
Packaging
We participate in the recycling programmes of the countries in
which our products are sold to ensure optimum recycling.
All of our packaging materials are environmentally compatible
and can be recycled.
Electrical and electronic equipment
Scrap electrical and electronic
equipment must be collected separately
and returned to an environmentally
compatible recycling facility (European
Directive on waste electrical and
electronic equipment).
Use the country specific return and
collection system for the disposal of
electrical and electronic equipment.
Battery recycling
Batteries, rechargeable or not, must not be disposed of into
ordinary household waste. Instead, they must be recycled
properly to protect the environment and cut down on the waste
of precious resources. Your local waste management authority
can supply details concerning the proper disposal of batteries.
Supplier Worcester Bosch Group
Model Comfort II
ErP Class V
Function and
ERP
description
Load compensation
Modulating room thermostat, for use with
modulating heaters: An electronic room
thermostat that varies the flow
temperature of the water leaving the heater
dependant upon measured room
temperature deviation from room
thermostat set point. Control is achieved
by modulating the output of the heater.
Additional
seasonal
space
heating
efficiency
gain
+3%

WORCESTER, BOSCH GROUP:
TECHNICAL SUPPORT: 0330 123 3366
APPOINTMENTS: 0330 123 9339
SPARES: 0330 123 9779
LITERATURE: 0330 123 9119
TRAINING: 0330 123 0166
SALES: 0330 123 9669
Worcester, Bosch Group
Cotswold Way, Warndon, Worcester WR4 9SW.
Tel. [phone]
Worcester, Bosch Group is a brand name of
Bosch Thermotechnology Ltd.
worcester-bosch.co.uk
Comfort II 6 720 810965 (2017/02) *2703726_REV1*