Worcester GB162-50 V2 User guide

6720814332 (2019/04) GB
Installation, commissioning and servicing instructions
Wall hung gas fired condensing boilers
Worcester Commercial Boiler Series
GB162-50/65/85/100 V2

Table of contents
Worcester Commercial Boiler Series – 6720814332 (2019/04)
2
Table of contents
1 Explanation of symbols and safety instructions . . . . . . . . . . . 3
1.1 Explanation of symbols . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 General safety instructions . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Regulations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 Appliance information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Declaration of conformity . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Appliance types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Data plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.4 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.5 LPG conversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.6 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.7 Removing the casing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.8 Anti-Freeze Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.9 Pump anti-seizure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.10 Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.11 Product overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.12 Wiring diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2.13 Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.14 Product data on energy consumption. . . . . . . . . . . . . . 11
2.15 Gas specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.16 Hydraulic resistances. . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.17 Residual head. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3 Pre-Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
3.1 Cleaning primary systems . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Water quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3 Mains supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3.1 Electrical supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3.2 Gas supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.4 Water systems and pipe work . . . . . . . . . . . . . . . . . . . . 13
3.5 Condensate pipe work. . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.5.1 Internal connections . . . . . . . . . . . . . . . . . . . . . . . . . . .15
3.5.2 External connections . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.6 Pressure relief pipe work. . . . . . . . . . . . . . . . . . . . . . . . 17
3.7 Boiler location and clearances . . . . . . . . . . . . . . . . . . . 18
3.7.1 Installation and servicing clearances . . . . . . . . . . . . . . 18
3.7.2 Compartments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.7.3 Bathrooms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
3.8 Flue options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.8.1 Air supply and flue gas exhaust in a room sealed
installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
3.8.2 Maximum Flue length (L) . . . . . . . . . . . . . . . . . . . . . . . . 19
3.8.3 Additional flue parts. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.8.4 Standard 100 mm flue systems . . . . . . . . . . . . . . . . . .20
3.8.5 Installation of the horizontal flue. . . . . . . . . . . . . . . . . . 20
3.8.6 Flue pipe preparation and assembly. . . . . . . . . . . . . . . 20
3.9 Flue gas connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.9.1 Open flue operation . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
3.9.2 Room sealed operation . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.9.3 Flue material. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
3.9.4 Calculating the air intake and flue gas pipe
dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.10 Flue terminal positions . . . . . . . . . . . . . . . . . . . . . . . . . 21
4 Transport. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5 Fitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
5.1 Unpacking the boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.2 Check gas type. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.3 Mounting the boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
5.4 Remove the protective caps . . . . . . . . . . . . . . . . . . . . . 23
5.5 Hydraulic and gas connections . . . . . . . . . . . . . . . . . . . 23
5.6 Mounting the pump group (accessory) . . . . . . . . . . . . 23
5.6.1 Installing the gas isolation valve . . . . . . . . . . . . . . . . . . 24
5.6.2 Mounting the pump group . . . . . . . . . . . . . . . . . . . . . . . 24
5.7 Hydraulic and gas connections (without pump
group). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
5.7.1 Gas connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.7.2 Mounting the pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.8 Install the low loss header . . . . . . . . . . . . . . . . . . . . . . . 25
5.9 Installing the siphon. . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
5.10 Connecting the condensate drain. . . . . . . . . . . . . . . . . 26
5.11 Expansion vessel connection . . . . . . . . . . . . . . . . . . . . 26
5.12 Mounting the back panel insulation . . . . . . . . . . . . . . . 27
6 Electrical connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.1 Control principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
6.2 Connection of the control units. . . . . . . . . . . . . . . . . . . 28
6.3 Installation of the strain relief . . . . . . . . . . . . . . . . . . . . 28
6.4 Connecting the on/off room temperature-
dependent control unit . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.4.1 Connecting the RTH convertor (only for 50-V2 and
65-V2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.5 Connecting the modulating controller . . . . . . . . . . . . . 29
6.6 Connecting an external switching contact . . . . . . . . . . 29
6.7 Connecting an outside temperature sensor
(accessory) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
6.8 Connecting a cylinder temperature sensor . . . . . . . . . 30
6.9 Connecting the 3-way valve. . . . . . . . . . . . . . . . . . . . . . 30
6.10 Connecting the function module (accessory) . . . . . . . 30
6.11 Connecting the cylinder primary pump . . . . . . . . . . . . 30
6.12 Connecting the hot water circulation pump . . . . . . . . . 30
6.13 Connecting the pump . . . . . . . . . . . . . . . . . . . . . . . . . . 30
6.14 Connecting to the mains . . . . . . . . . . . . . . . . . . . . . . . . 30
7 Operating the boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.1 Information menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
7.2 Setup menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.3 Chimney sweep mode . . . . . . . . . . . . . . . . . . . . . . . . . . 32
7.4 „Fault history“ menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
7.5 Key lock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8 Commissioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.1 Filling the heating system . . . . . . . . . . . . . . . . . . . . . . . 33
8.2 Purging the gas line . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
8.3 Inspecting the flue system. . . . . . . . . . . . . . . . . . . . . . . 33
8.4 Adjusting the output . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.5 Setting the maximum boiler temperature. . . . . . . . . . . 34
8.6 Adjusting the pump group . . . . . . . . . . . . . . . . . . . . . . . 34
8.7 Testing the gas supply pressure . . . . . . . . . . . . . . . . . . 34
8.8 Measure gas/air ratio . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
8.9 Measure the CO and CO2 content . . . . . . . . . . . . . . . . 36

Table of contents
3
Worcester Commercial Boiler Series – 6720814332 (2019/04)
1 Explanation of symbols and safety instructions
1.1 Explanation of symbols
Warnings
In warnings, signal words at the beginning of a warning are used to
indicate the type and seriousness of the ensuing risk if measures for
minimising danger are not taken.
The following signal words are defined and can be used in this document:
DANGER:
DANGER indicates that severe or life-threatening personal injury will
occur.
WARNING:
WARNING indicates that severe to life-threatening personal injury may
occur.
CAUTION:
CAUTION indicates that minor to medium personal injury may occur.
NOTICE:
NOTICE indicates that material damage may occur.
Important information
The info symbol indicates important information where there is no risk to
people or property.
Additional symbols
Table 1
8.9.1 CO and combustion checks . . . . . . . . . . . . . . . . . . . . . .36
8.10 Measure ionisation current . . . . . . . . . . . . . . . . . . . . . .37
8.11 Testing for gas leaks . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
8.12 Check the operating characteristics of the boiler. . . . .38
8.13 Final steps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
8.14 Inform the user . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
8.15 Commissioning report (for installations below
70 kW) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
9 Shutdown. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
9.1 Standard shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
9.2 Shutting down when there is a risk of frost . . . . . . . . . .39
10 Environmental protection/disposal. . . . . . . . . . . . . . . . . . . . .39
11 Inspection and servicing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39
11.1 Important information . . . . . . . . . . . . . . . . . . . . . . . . . .39
11.2 Remove the gas-air unit . . . . . . . . . . . . . . . . . . . . . . . . .39
11.3 To clean the burner. . . . . . . . . . . . . . . . . . . . . . . . . . . . .40
11.4 Cleaning the heat exchanger . . . . . . . . . . . . . . . . . . . . .41
11.5 Checking the ignition system . . . . . . . . . . . . . . . . . . . . .41
11.6 Clean condensate trap/siphon . . . . . . . . . . . . . . . . . . .42
11.7 Cleaning the condensate sump . . . . . . . . . . . . . . . . . . .42
11.8 Testing the gas supply pressure. . . . . . . . . . . . . . . . . . .43
11.9 Measure gas/air ratio . . . . . . . . . . . . . . . . . . . . . . . . . . .43
11.10 Measure CO/CO2 content . . . . . . . . . . . . . . . . . . . . . . .44
11.11 Check flue gas non-return valve. . . . . . . . . . . . . . . . . . .44
11.12 Measure ionisation current . . . . . . . . . . . . . . . . . . . . . .44
11.13 Testing for gas leaks . . . . . . . . . . . . . . . . . . . . . . . . . . . .44
11.14 Check for correct operating characteristics . . . . . . . . .44
11.15 Inspection and maintenance reports. . . . . . . . . . . . . . .44
12 Display codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
12.1 Code types in the display. . . . . . . . . . . . . . . . . . . . . . . .45
12.2 Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45
12.3 Operating and fault codes . . . . . . . . . . . . . . . . . . . . . . .45
12.4 Service record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Symbol Meaning
 a step in an action sequence
a reference to a related part in the document
• a list entry
– a list entry (second level)

Explanation of symbols and safety instructions
Worcester Commercial Boiler Series – 6720814332 (2019/04)
4
1.2 General safety instructions
HPleasereadthese instructions carefully before
starting installation.
• These instructions are applicable to the Worcester
appliance model(s) stated on the front cover of this
manual only and must not be used with any other
make or model of appliance.
• These instructions apply in the UK and Ireland only
and must be followed except for any statutory
obligations.
• This appliance must be installed by a competent
registered gas engineer, such as a Gas Safe
registered engineer including a British Gas
engineer. Failure to install correctly could lead to
prosecution.
• If you are in any doubt, contact the Worcester
Technical help-line
(0330 123 3366).
• Distance learning and training courses are available
from Worcester.
• The BENCHMARK Commissioning Checklist can be
found on page 50 of this Installation manual.
Abbreviations used in this manual
HNotices for the target group
These installation instructions are intended for gas,
plumbing, heating and electrical contractors. All
instructions must be observed. Failure to comply with
instructions may result in material damage and
personal injury, including danger to life.
 Read the installation instructions (heat source,
heating controller, etc.) before installation.
 Observe the safety instructions and warnings.
 Follow national and regional regulations, technical
regulations and guidelines.
 Record all work carried out.
HDetermined use
The product may only be used in a domestic situation
for the heating of central heating water and for DHW
heating in closed-loop DHW and heating systems.
Any other use is considered inappropriate. Any
damage that may result from misuse is excluded from
liability.
If you smell gas
A gas leak could potentially cause an explosion. If you smell gas, observe
the following rules.
 Prevent flames or sparks:
– Do not smoke, use a lighter or strike matches.
– Do not operate any electrical switches or unplug any equipment.
– Do not use the telephone or ring doorbells.
 Turn off the gas at the meter or regulator.
 Open windows and doors.
 Warn your neighbours and leave the building.
 Prevent anyone from entering the building.
 Well away from the building: call the National Gas Emergency Service
on 0800 111 999.
 L.P.G. boilers: Call the supplier’s number on the side of the gas tank.
HDanger to life from poisoning by flue gas
There is a danger to life from escaping flue gas.
 Ensure that flues and gaskets are not damaged.
HDanger of death from poisoning by flue gas due
to inadequate combustion
Danger of death due to flue gas leak. If flues are
damaged or leaking, or if you smell flue gas, observe
the following rules.
 Close the fuel infeed.
 Open doors and windows.
 If necessary, warn all residents and leave the
building.
 Prevent third parties from entering the building.
 Rectify any damage to the flue gas pipe
immediately.
 Check the combustion air supply.
 Do not cover or reduce the size of ventilation
openings in doors, windows and walls.
 Ensure that there is adequate combustion air
supply, including for any appliances installed at a
later date, e.g. extractor fans, kitchen fans or air
conditioning units that discharge air to the outside.
 Never operate the device if there is insufficient
combustion air supply.
HInstallation, commissioning and maintenance
Installation, commissioning and maintenance must
only be carried out by an approved contractor.
 Carry out a gas tightness test after completing work
on gas-carrying components.
Ø Diameter
NG Natural Gas
LPG Liquid Petroleum Gas
CH Central Heating
DHW Domestic Hot Water
HE Heat exchanger
DCW Domestic Cold Water
PRV Pressure Relief Valve
NTC Negative Temperature Coefficient (sensor)
IP Ingress Protection
RCD Residual Current Device
TRV Thermostatic Radiator Valve
ECV Emergency Control Valve
ErP Energy related Products

Explanation of symbols and safety instructions
5
Worcester Commercial Boiler Series – 6720814332 (2019/04)
 In the case of open flue operation:Ensure that the
installation location meets the ventilation
requirements.
 Only use original spares.
HElectrical work
Electrical work must only be carried out by electrical
installation contractors.
Before starting electrical work:
 Isolate all poles of the mains voltage and secure
against reconnection.
 Make sure the mains voltage is disconnected.
 Observe the wiring diagrams of other system
components as well.
HServicing
Advise the user to have the system serviced annually
by a competent, registered gas engineer, such as a Gas
Safe registered engineer or British Gas engineer.
Approved spares must be used to help maintain the
efficiency, safety and reliability of the appliance.
HBenchmark Service Record
The service engineer must complete the Benchmark
Service Record at the back of this manual after each
service.
Benchmark places
responsibilities on both
manufacturers and
installers.
The purpose is to ensure that customers are provided
with the correct equipment for their needs, that it is
installed, commissioned and serviced in accordance
with the manufacturer's instructions by competent
persons and that it meets the requirements of the
appropriate Building Regulations. The Benchmark
Checklist can be used to demonstrate compliance
with Building Regulations and should be provided to
the customer for future reference.
Installers are required to carry out installation,
commissioning and servicing work in accordance with
the Benchmark Code of Practice which is available
from the Heating and Hot water Industry Council who
manage and promote the scheme.
Visit centralheating.co.uk for more information.
HHandover to the user
When handing over, instruct the user how to operate
the heating system and inform the user about its
operating conditions.
 Explain how to operate the heating system and draw
the user's attention to any safety relevant action
 Explain that conversions and repairs must only be
carried out by a competent person.
 Point out the need for inspections and maintenance
for safe and environmentally-compatible operation.
 Leave the installation instructions and the
operating instructions with the user for
safekeeping.
Combustible and corrosive materials
Do not store or use any combustible materials (paper, thinners, paint
etc.) inside or close to the appliance.
Chemically aggressive substances, such as halogenated hydrocarbons.
The presence of halogenated hydrocarbons in the combustion air causes
surface corrosion on affected metals.
In order to limit the damage, the source of the air contamination must be
located and sealed off. If this is not possible, the combustion air must be
drawn from an alternative clean source.
HFitting and modification
Fitting the appliance and any controls to the appliance
may only be carried out by a competent engineer in
accordance with the current Gas Safety (Installation
and Use) Regulations.
Flue systems must not be modified in any way other
than as described in the fitting instructions. Any
misuse or unauthorised modifications to the
appliance, flue or associated components and
systems could invalidate the warranty. The
manufactureraccepts no liability arising fromanysuch
actions, excluding statutory rights.
HSafety of electrical devices for domestic use
and similar purposes
The following requirements apply in accordance with
EN 60335-1 in order to prevent hazards from
occurring when using electrical appliances:
“This appliance can be used by children of 8 years and
older, as well as by people with reduced physical,
sensory or mental capabilities or lacking in experience
and knowledge, if they are supervised and have been
given instruction in the safe use of the appliance and
understand the resulting dangers. Children shall not
play with the appliance. Cleaning and user
maintenance must not be performed by children
without supervision.”
“If the power cable is damaged, it must be replaced by
the manufacturer, its customer service department or
a similarly qualified person, so that risks are avoided.”

Appliance information
Worcester Commercial Boiler Series – 6720814332 (2019/04)
6
1.3 Regulations
Installation regulations
Current Gas Safety (Installation and Use) Regulations:
All gas appliances must be installed by a competent, registered gas
engineer, such as a Gas Safe registered engineer or British Gas engineer
in accordance with the current regulations.
Failure to install appliances correctly could lead to prosecution.
The appliance must be installed in accordance with, and comply to, the
current:
Gas Safety Regulations, IET Regulations, Building Regulations, Building
Standards (Scotland) (Consolidation),
Building Regulations (Northern Ireland), local water by-laws,
Health and Safety Document 635 (The Electricity at Work Regulations
1989) and any other local requirements.
EU Regulations No. 811/2013 - Energy Labelling.
British Standards
Where no specific instruction is given, reference should be made to the
relevant British Standard codes of Practice.
BS7074:1 Code of practice for domestic and hot water supply
BS6891 Installation of low pressure gas pipe work up to 28mm (R1)
BS5546 Installation of gas hot water supplies for domestic purposes
EN12828 Central heating for domestic premises
BS5440:1 Flues and ventilation for gas appliances of rated heating not
exceeding 70kW (net): Flues
BS5440:2 Flues and ventilation for gas appliances of rated heating not
exceeding 70kW (net): Air Supply
BS7593 Treatment of water in domestic hot water central heating
systems
BS6798 Installation of gas fired boilers of rated input up to 70kW (net)
Irish Standards
The current relevant Irish standards should be followed, including:
• ECTI
– National rules for electrical installations
• IS 813
– Domestic Gas Installations
LPG Installations
An appliance using LPG must not be installed in a room or internal space
below ground level unless one side of the building is open to the ground.
Timber framed buildings
Where the appliance is to be fitted to a timber framed building the
guidelines laid down in BS5440: Part 1 and IGE “Gas Installations in
Timber Frame Buildings” should be adhered to.
Potable water
All seals, joints and compounds (including flux and solder) and
components used as part of the secondary domestic water system must
be approved by WRAS.
CH Water
Salt based artificially softened water must not be used to fill the central
heating system.
2 Appliance information
2.1 Declaration of conformity
The design and operating characteristics of this product comply with the
European and national requirements.
The CE marking declares that the product complies with all the
applicable EU legislation, which is stipulated by attaching this
marking.
The complete text of the Declaration of Conformity is available on the
Internet: worcester-bosch.co.uk.
2.2 Appliance types
Table 2
This document refers to the following appliance types:
• GB162-50 V2
• GB162-65 V2
• GB162-85 V2
• GB162-100 V2
The designation of the boiler comprises the following:
• Worcester: manufacturer
• GB162 V2: product name
• 50, 65, 85 or 100: type name (output)
2.3 Data plate
The data plate is on the top of the boiler to the left of the flue gas adaptor
(figure 4, [8]). The data plate contains the serial number, gas group
classification and approvals.
These appliances are for use with Natural Gas or L.P.G.
(Cat. II2H3P type C13, C33 & C53)
Model Gas Council Number
Natural gas 50 kW 41-406-66
65 kW 41-406-67

Appliance information
7
Worcester Commercial Boiler Series – 6720814332 (2019/04)
2.4 Scope of delivery
The boiler is supplied pre-assembled from the factory.
 Check that the delivery is complete and undamaged.
Fig. 1 Scope of delivery
[1] Wall mounted gas condensing boiler
[2] Mounting bracket
[3] Compression elbow
[4] Technical documentation
[5] Condensate trap
[6] RTH convertor (50-V2 and 65-V2 only)
[7] Condensate hose
[8] Screw, washer, rawl plug (2 × )
[9] Screw fitting with gasket (2 × )
[10] Strain relief (6 × )
2.5 LPG conversion
This boiler is approved for the gas type specified on the data plate. If the
boiler can be converted for another gas type, corresponding information
will be provided in the gas data (chapter 2.15, page 11).
2.6 Accessories
A wide range of accessories is available for the GB162 V2 boilers.
Please contact the manufacturer for further details. You will find the
relevant contact details on the back cover of these instructions.
2.7 Removing the casing
 Undo locking screws [1.].
 Pull the 2 click fasteners on the underside of the control panel down
[2.].
 Remove the casing [3.].
Fig. 2 Casing removal
2.8 Anti-Freeze Protection
NOTICE:
System damage.
The central heating system may freeze up during severe frost due to:
intermittent electricity supply, inadequate gas supply or an appliance
error.
 Install the boiler in a frost-free room.
 Drain the water from the central heating system if it will be out of
operation for an extended period.
The boiler is equipped with integral frost protection. This means that the
boiler requires no external frost protection system. The frost protection
system fires the boiler at a boiler temperature of 7 °C and will operate the
circulating pump until a boiler temperature of 15 °C is reached.
The boiler does not guarantee the protection of the entire heating system
from frost.
0010025975-001
3
5
4
10
1
9
8
7
6
2
0010020123-001
1. 1.
2.
3.
3.

Appliance information
Worcester Commercial Boiler Series – 6720814332 (2019/04)
8
2.9 Pump anti-seizure
The pump starts automatically for 10 seconds every 24 hours if the
pump has not been operated during this time. This procedure prevents
the pump from seizing.
2.10 Dimensions
Fig. 3 Dimensions [mm]
[1] Concentric flue, Ø 80/125 mm (50-V2 and 65-V2) or
Ø 100/150 mm (85-V2 and 100-V2)
[2] Ventilation panel
[3] Gas connection for boiler, R 1'' male thread
[4] Heating return, G 1½ '' screw fitting with female thread
[5] Pump group for return, G 1½ '' male thread with flat seal
[6] Condensate pipe, Ø external diameter 24 mm
[7] Pump group for gas connection, R 1" female thread
[8] Pump group for flow, G 1½ '' male thread with flat gasket
[9] Heating flow, G 1½ '' screw fitting with female thread
0010009975-001
520
= = 469
1326
980
140
156
330
130
= = 40
6
35
138
4
21
1
9
5
6
8
6
7
3

Appliance information
9
Worcester Commercial Boiler Series – 6720814332 (2019/04)
2.11 Product overview
Fig. 4 GB162 V2 with pump group
0010025976-001
3
5
6
815
17
18
19
20
21
22
23
24
26
25
28
31
29
30
3227
16
10 11 12 13 149
4
7
2
33
34
31
1
35
Wall mounted gas condensing boiler:
[1] Control panel
[2] Terminal strip
[3] Condensate sump
[4] Burner cover release clips
[5] Auto air vent
[6] Air intake pipe
[7] Venturi nozzle
[8] Data plate
[9] Gas valve
[10] Combustion air connection
(concentric)
[11] Flue gas connection (concentric)
[12] Flue gas testing point
[13] Flue gas temperature sensor
[14] Incoming air testing point
[15] Cap, combustion air connection
(overpressure flue)
[16] Flue pipe
[17] Fan
[18] Burner
[19] Ignition device
[20] Flow temperature sensor
[21] Safety temperature sensor
[22] Pressure sensor
[23] Heat Exchanger
[24] Return temperature sensor
[25] Boiler ID module (KIM)
[26] Locking screw
[27] Condensate trap
Pump group (accessory):
[28] Pump
[29] Drain & fill valve (DFV)
[30] Expansion vessel connection
[31] Hydraulic isolation valves
[32] Gas isolation valve
[33] Drain cock
[33] Pressure gauge
[34] Pressure Relief Valve

Appliance information
Worcester Commercial Boiler Series – 6720814332 (2019/04)
10
2.12 Wiring diagram
Fig. 5 Wiring diagram
[1] Fan
[2] Transformer
[3] Glow ignitor
[4] Gas valve type 50-V2 and 65-V2
[5] Gas valve type 85-V2 and 100-V2
[6] Boiler ID module (KIM)
[7] Burner control unit
[8] Control panel
[9] Pressure sensor
[10] Return temperature sensor
[11] Flue gas temperature sensor (cascade flue accessory)
[12] Flow temperature sensor
[13] Safety temperature sensor
[14] Flame sense electrode
[15] Earth
[16] Turquoise - no function
[17] Grey - no function
[18] Blue - outside temperature sensor
[19] Red - external switching contact (link added as standard)
[20] Orange - modulating temperature controller
[21] Green - on/off room temperature-dependent controller /
RTH convertor (included in 50-V2 and 65-V2 delivery)
[22] Pump control signal PWM
[23] On/off switch
[24] Grey - no function
[25] White - power supply 230 V AC, 50 Hz
[26] Orange - power supply of the 1st function module 230 V AC
[27] Purple - no function
[28] Green - pump group or external
[29] Pump group, external pump 230 V AC, max. 250 W
0010025977-001
D17 D13 D16
C4 C3 C8 C7 A8 A7 A2 A1 A4 A5
G6 G5
F2 F1
0V
24V
13 12 11 10 9 8 7 6 5 4 3 2 1
12 34
0 VAC
24 VAC
PEPE
10
F2 F1
PE
F4
F3
PE
G2 G1
PE
L
PE
N
A9
C10
B12
B13
C9
1
2
3
B16
B17
C1
C2
C14
C17
D9
D10
A6
B2
A11
A12
D14
D12
D11
D1
D3
C16
C15
1
2
3
4
5
1
2
3
4
5
A14
A13
A16
A15
6
7
24 VAC
0 VAC
24 VAC
10 VAC
10 VAC
230 VAC
230 VAC
24 V RAC 1
2
3
4
5
D6
D7
24 VAC
1
2
3
4
D5
D8
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
E1
E2
E3
E4
E5
E6
E7
E8
B7 B3 B6
B14
B15 11
1
2
3
4
5
8
7
9
10
12
13
14 15
29
16 17
19
20 21 26 27
18
23
22
24 25 28
6

Appliance information
11
Worcester Commercial Boiler Series – 6720814332 (2019/04)
2.13 Specifications
Table 3 Specifications
The information in brackets corresponds to the information on the data
plate.
2.14 Product data on energy consumption
The product data on energy consumption can be found in the operating
instructions for the user.
2.15 Gas specification
Gas consumption
Table 4 Gas consumption
50-V2 65-V2 85-V2 100-V2
General Information Unit
Rated output G20 (50/30 °C) [Pncond] kW 14.3 – 49.9 14.3 – 69.5 20.8 – 84.5 20.8 – 99.5
Rated output G20 (80/60 °C) [Pn] kW 13.0 – 46.5 13.0 – 62.6 18.9 – 80.0 19.0 – 94.5
Rated input G20 [Qn(Hi)] kW 13.3 – 47.5 13.3 – 64.3 19.3 – 82.0 19.3 – 96.5
Efficiency G20 (37/30 °C) partial load 30% in accordance with
EN 15502
% 108.3 108.4 109.4 109.5
Efficiency G20 (80/60 °C) full load % 98.2 98.0 98.4 97.8
Standby loss in accordance with EN 15502 % 0.18 0.14 0.11 0.09
Pump over-run time min 5
Residual head of fan (pmax) Pa 85 130 195 220
IP classification [IP rating] IP X4D (B23, B33: X0D)
Flue categorisation (according to EN 15502) B23, B33, C13, C33, C43, C53, C63, C83, C93
Temperature classification in accordance with EN 14471 T120
Appliance fuse 230 V, 5AF
Mains voltage, frequency [U] 230 V, 50 Hz
Electrical power consumption (without a pump group),
standby / partial load / full load
W 6 / 18 / 41 6 / 18 / 82 6 / 25 / 102 6 / 25 / 155
Permissible ambient temperature °C 0 - 40
Maximum flow temperature [Tmax] °C 90
Maximum operating pressure [PMS] bar 4
Maximum condensate accumulation rate l/h 6.0 7.6 9.3 11.0
Connections
Flue gas connection/concentric air supply mm 80/125 100/150
Heating flow/return pipe (boiler) inch G1½
Gas connection (boiler) inch R1
Condensate drain (flexible hose external diameter) mm 24
Emission levels in accordance with EN 13384
CO2content with natural gas G20, partial load/full load % 8.9 / 9.3 8.9 / 9.3 8.9 / 9.3 8.9 / 9.3
CO output G20 at full load ppm 33 57 83 100
NOx,pond, Hs EN 15502 modulating Qn mg/kWh 21 32 39 42
NOxclass 5
Flue gas mass flow rate at max. rated output g/s 22.2 29.8 37.7 43.8
Flue gas temperature at 80/60 °C, partial load/full load °C 57 / 60 57 / 62 57 / 66 57 / 68
Flue gas temperature at 50/30 °C, partial load/full load °C 34 / 39 34 / 39 34 / 49 34 / 53
Differential pressure gas/air (with partial load) Pa - 5
Dimensions and weight
Height x width x depth mm 980 x 520 x 465
Height x width x depth including pump group mm 1329 x 520 x 465
Weight (dry) kg 70
Pump group
Heating flow pipe inch G1½
Heating return pipe, male thread with flat gasket inch G1½
Gas inch G 1
Electrical power consumption WILO Stratos PARA 25/1-8, min./max. W 8 / 140
Maximum current drawn WILO Stratos PARA 25/1-8 A 0.95
Maximum gas consumption m³/h
Gas type 50-V2 65-V2 85-V2 100-V2
Natural gas E, H, Es(G20) 5.03 6.81 8.68 10.24
Propane 3P (G31) 1.80 2.48 3.19 3.76

Appliance information
Worcester Commercial Boiler Series – 6720814332 (2019/04)
12
Gas supply pressures
Table 5 Gas supply pressures
Natural gas
Table 6 Natural gas
2.16 Hydraulic resistances
Table 7 Hydraulic resistances
Fig. 6 Resistance graph per type
[l/h] Flow rate
[mbar]Pressure drop
2.17 Residual head
Fig. 7 Residual head per boiler type, with pump group and non-return
valve
[A] Resistance of boiler
[l/h] Flow rate
[mbar]Residual head
[min.]Residual head at minimum pump speed
Fig. 8 Residual head per boiler type, with pump group
[A] Resistance of boiler
[l/h] Flow rate
[mbar]Residual head
[min.]Residual head at minimum pump speed
Gassupplypressure
[mbar]
Country Gas category Min. Rated Max.
GB, IE Natural gas H, G20 171)
1) Can be reduced by 3 mbar if measured at the inlet of the gas valve.
20 25
GB, IE Propane, G31
(conversion
required)
251) 37 45
Country Gas design
pressure
[mbar]
Gas
category
Gas family Default
setting [mbar]
GB, IE 20 2H 2H, G20 20
Appliance type
Unit 50-V2 65-V2 85-V2 100-V2
Required flow rate at
T = 20 K
l/h 2200 3000 3600 4300
Max. flow rate at T = 20 K l/h 5000
Resistance of boiler with
required flow rate
mbar 90 170 225 320
001002647-001
500
450
400
350
300
250
200
150
100
50
0500 1000 1500 2000 2500 3000 3500 4000 4500 5000
[l/h]
[mbar]
100 kW
85 kW
65 kW
50 kW
0010025979-001
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
[mbar]
[l/h]
65-V2
50-V2
85-V2
min.
100-V2
[A]
0010025980-001
0
50
100
150
200
250
300
350
400
450
500
550
600
650
700
750
800
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
[mbar]
[l/h]
65-V2
85-V2
50-V2
min.
100-V2
[A]

Pre-Installation
13
Worcester Commercial Boiler Series – 6720814332 (2019/04)
3 Pre-Installation
3.1 Cleaning primary systems
CAUTION:
 Isolate the mains supplies before starting any work and observe all
relevant safety precautions. Guard against unintentional re-
connection.
NOTICE:
 All the following pre-installation sections must be read and
requirements met before starting the boiler or flue installations.
NOTICE:
 Debris from the system can damage the boiler and reduce efficiency.
Failure to comply with water treatment guidelines will invalidate the
appliance guarantee and contravene the Building Regulations.
 It is recommended that you fit a primary water cleanser to the
system. Worcester recommends a filter that will help remove both
magnetite and non-magnetic debris.
Before cleaning the system:
 Ensure that the system and pipe work is in good working order.
 Where possible keep the existing boiler/circulating pump in place
when flushing the system.
3.2 Water quality
Unsuitable or contaminated heating water can lead to faults in the boiler
and can damage the heat exchanger, among other things, due to sludge
formation, corrosion or lime scale deposits. Please get in touch with the
manufacturer if you require additional information on the water quality.
You will find the relevant addresses on the back cover of these
instructions.
 Do not use any chemical additives (e.g. inhibitors or pH-increasing or
reducing agents) other than those approved by Bosch
Thermotechnology (table 8). The pH of the heating system water
must be between 7 and 8.5. If this is not the case, please contact
Worcester Customer Service before proceeding.
Table 8 Approved inhibitors by Bosch Thermotechnology Ltd.
3.3 Mains supply
NOTICE:
This boiler must not be connected to a 3 phase supply.
3.3.1 Electrical supply
• Supply: 230V - 50 Hz, 130 Watts
• Cable: PVC insulated H05VVF 3G1 (3 x 1mm2) temperature rated to
90 °C.
• External 3A fuse to BS1362.
• The boiler must be earthed.
• IPX4D.
• Wiring must comply with the latest edition of BS 7671 (IEE wiring
regulations).
3.3.2 Gas supply
• Boilers using Natural Gas (NG) must be connected to a governed
meter.
• Liquid Petroleum Gas (LPG) must be connected to a regulator.
• Installation and connection of the gas supply to the appliance must
be in accordance with BS6891 or IGE/UP/2 as appropriate.
• Gas pipe sizing should be calculated to ensure no more than the
permitted pressure drop between the meter/governor to the
appliance inlet (Commissioning section).
• The meter or regulator and pipe work to the meter must be checked,
preferably by the gas supplier.
• This is to ensure that the equipment is in good working order and can
meet the gas flow and pressure requirements, in addition to the
demand from any other appliance being served.
3.4 Water systems and pipe work
If the boiler is used in heating systems with natural water circulation or
open systems (where heating water is in contact with outdoor air):
 Install a system separation solution (a plate heat exchanger for
example) between the boiler and the heating system
If plastic pipes are used in the heating system, with an underfloor heating
system for example,
 use plastic pipes with sufficient oxygen diffusion resistance
-or-
 Install a system separation solution (a plate heat exchanger for
example) between the boiler and the heating system.
Plastic pipe work:
• Any plastic pipe work must have a polymeric barrier with 600mm
(minimum) length of copper pipe before being connected to the
boiler.
• Plastic pipe work used for underfloor heating must be correctly
controlled with a thermostatic blending valve limiting the
temperature of the circuits to approximately 50 °C.
Primary systems connections/valves:
• All system connections, taps and mixing valves must at least be
capable of sustaining a pressure equal to the opening pressure of the
PRV used.
• Radiator valves should conform to BS2767:10.
• All other valves should conform to BS1010.
• Thermostatic radiator valves (TRV’s) must be fitted to all rooms
except bathrooms and the room in which the room thermostat is
fitted.
• A drain cock is required at the lowest point(s) in the system.
• An air vent is required at the high point(s) in the system.
An external automatic bypass should be used if the system flow can be
significantly adjusted or stopped by zone valves and thermostatic
radiator valves (TRV).
Sealed primary system:
NOTICE:
Artificially softened water must not be used to fill the central
heating system.
• The CH sealed system must be filled using a WRAS approved filling
method or comply with figure 10 for system fill.
• An expansion vessel must be fitted as close as possible to the
appliance in the central heating return. When a pump group is used,
see Chapter 5.11.
• Do not use galvanised pipes or radiators.
Product Concentration
Fernox F1 See Fernox product data sheet
Sentinel X100 See Sentinel product data sheet

Pre-Installation
Worcester Commercial Boiler Series – 6720814332 (2019/04)
14
System fill:
Filling and refilling of the heating circuit must have been carried out by a
method that has been approved by the Water Regulation Advisory
Scheme (WRAS), for the type of heating appliances, i.e. Domestic (in-
house) Fluid Category 3. Non-Domestic (other than in-house) Fluid
Category 4. Depending on the Fluid Category the approved method
should comprise of the following:
Requirements Fluid Category 3 systems:
• Control valve (stop valve) including a double check valve on the mains
cold water supply pipe.
• Temporary connection to be removed after filling (filling loop).
• Control valve (stop valve) on the heating system pipework.
Fig. 9 System fill - category 3
Requirements Fluid Category 4 systems:
• Control valve (stop valve) on the mains cold water supply pipe.
• Strainer.
• Water non-return valve with reduced pressure Zone (RPZ valve
assembly) incorporating a Type BA air gap.
• Tundish.
• Control valve (stop valve) on the heating system pipework.
Fig. 10 System fill - category 4
Typical sealed system
Fig. 11 Sealed system
[1] Expansion vessel - CH return
[2] Pressure relief discharge
[3] Drain cock
[4] Radiators
Fig. 12 Sealed system with zone valves
[1] Expansion vessel - CH return
[2] Pressure relief discharge
[3] Drain cock
[4] Radiators
[5] Zone valves
3.5 Condensate pipe work
NOTICE:
 Where a new or replacement boiler is being installed, access to an
internal “gravity discharge” point should be one of the factors
considered in determining boiler location.
 The condensate pipe must be nominally 22mm Ø plastic pipe.
 The condensate pipe work must fall at least 52mm per metre towards
the outlet and should take the shortest practicable route.
 Ensure there are no blockages in the pipe run.
Table 9
0010025981-001
Heating return
SYSTEM FILL
Hose
return
Stop
cock Test cock
Non return
valve Non return
valve
Mains
supply
Temporary hose
Stop cock
0010025982-001
Mains
cold water
Stop
cock
Stop
cock
Strainer RPZ
Tundish
0010025983-001
3
3
1
2
4 4
44
Key to condensate illustrations
1 Condensate discharge from boiler
2 Soil and vent stack
3 Minimum 450mm and up to three storeys
4 Visible air break at plug hole
5 Sink or basin with integrated overflow
6 75mm sink waste trap
7 Condensate pump
8 PVCu strap on fitting
9 100mm Ø minimum plastic pipe
10 Drainage holes
11 Limestone chippings
12 Bottom of sealed tube
13 Insulate and increase pipe size
14 Pipe work transition
15 External air break
16 Air gap
17 External rain water pipe into foul water
18 43mm 90° male/female bend
* Condensate trap of 75mm already incorporated into the
boiler
0010025984-001
M
M
3
5
3
1
2
4 4
44

Pre-Installation
15
Worcester Commercial Boiler Series – 6720814332 (2019/04)
3.5.1 Internal connections
In order to minimise risk of freezing during prolonged cold spells, the
following methods of installing condensate drainage pipe should be
adopted, in order of priority.
Wherever possible, the condensate drainage pipe should be routed and
terminated so that the condensate drains away from the boiler under
gravity to a suitable internal foul water discharge point such as an
internal soil and vent stack. A suitable permanent connection to the foul
waste pipe should be used.
Fig. 13 Disposal to soil vent stack
Alternatively if the first option is not possible an internal kitchen or
bathroom waste pipe, washing machine waste pipe etc. can be used.
Ensure that the condensate drain pipe is connected “down stream” of
the waste trap.
Fig. 14 Disposal to a waste pipe
[1] Condensate discharge from boiler
[4] Visible air break at plug hole
[5] Sink or basin with integrated overflow
[6] 75mm sink waste trap
Condensate pump
Where “gravity discharge” to an internal termination is not physically
possible, or where very long internal runs would be required to reach a
suitable discharge point, condensate should be removed using a
proprietary condensate pump, of a specification recommended by the
boiler or condensate pump manufacturer.
The pump outlet pipe should discharge to a suitable internal foul water
discharge point such as an internal soil and vent stack, internal kitchen
or bathroom waste pipe, washing machine waste pipe etc. A suitable
permanent connection to the foul waste pipe should be used.
Fig. 15 Condensate pump disposal
[1] Condensate discharge from boiler
[4] Visible air break at plug hole
[5] Sink or basin with integrated overflow
[6] 75mm sink waste trap
[*] Condensate trap of 75mm already incorporated into the boiler
3.5.2 External connections
NOTICE:
Freezing conditions
 Pipe work length should be kept to a minimum and the route as
vertical as possible.
 Weather proof insulation must be used.
NOTICE:
Condensate waste
 Care should be taken when siting a soak-away to avoid obstructing
existing services.
If no other discharge method is possible then the use of an externally run
condensate drainage pipe terminating at a suitable foul water discharge
point, or purpose-designed soak away, may be considered. If this
method is chosen then the following measures should be adopted:
 The external run be kept as short as possible and not exceed three
metres.
 The pipe should be run internally as far as possible before going
externally and the pipe diameter should be increased to 32mm
before it passes through the wall to the exterior. The pipe should be
insulated using suitable waterproof and weather resistant insulation.
 The external pipe should take the shortest and least exposed route to
the discharge point, and should “fall” as steeply as possible away
from the boiler, with no horizontal runs in which condensate might
accumulate.
 The use of fittings, elbows etc. should be kept to a minimum and any
internal “burrs” on cut pipe work should be removed so that the
internal pipe section is as smooth as possible.
Fitting an external air break
• Refer to figure 16 when a rain water down pipe is used to dispose of
condensate.
• An air break must be installed in the 43mm pipe work, between the
boiler condensate outlet and the drainpipe, outside the property, to
avoid flooding during adverse weather conditions.
0010025985-001
*
2
22mm Ø
1
3
0010025986-001
*
100mm
75mm
min.
4
6
1
22mm Ø
5
0010025987-001
*75mm
min.
4
7
5
6
1
22mm Ø

Pre-Installation
Worcester Commercial Boiler Series – 6720814332 (2019/04)
16
Fig. 16 Disposal into a rainwater down pipe
[1] Condensate discharge from boiler
[8] PVCu strap on fitting
[14] Pipe work transition
[15] External air break
[16] Air gap
[17] External rain water pipe into foul water
[18] 43mm 90° male/female bend
[*] Condensate trap of 75mm already incorporated into the boiler
Condensate drainage pipe can be run above or below ground.
Where the pipe terminates over an open drain or gully, the pipe should
terminate below the grating level, but above water level, in order to
minimise “wind chill” at the open end.
The use of a drain cover (such as those used to prevent blockage by
leaves) may offer further protection from wind chill.
Pipe drainage will be improved if the end is cut at 45° as opposed to a
straight cut.
Fig. 17 External disposal
[1] Condensate discharge from boiler
[13] Insulate and increase pipe size
[14] Pipe work transition
[*] Condensate trap of 75mm already incorporated into the boiler
Condensate soak away
• The condensate drainage pipe may be run above or below the ground
to the soak away. The examples shown on this page run above
ground.
• The soak away must use a 100mm Ø plastic tube with two rows of
three 12mm holes on 25mm centres and 50mm from the bottom of
the tube. The holes must face away from the house.
• The tube must be surrounded by at least 100mm of limestone
chippings to a depth of 400mm.
Minimum hole size for the condensate soak away must be 400mm deep
by 300mm Ø .
In situations where there are likely to be extremes of temperature or
exposure, the use of a proprietary trace-heating system for external pipe
work, incorporating an external frost thermostat, should be considered.
If such a system is used, the requirement to use 32mm pipe does not
apply. However, all other guidance above and the instructions for the
trace heating system, should be closely followed.
NOTICE:
Unheated internal areas.
 Internal pipe runs in unheated areas such as lofts, basements and
garages should be treated as external runs.
Fig. 18 Soak away
[1] Condensate discharge from boiler
[9] 100mm Ø minimum plastic pipe
[10] Drainage holes
[11] Limestone chippings
[12] Bottom of sealed tube
[13] Insulate and increase pipe size
[14] Pipe work transition
[*] Condensate trap of 75mm already incorporated into the boiler
0010025988-001
*
18 8
13
14
17
15
16
1
0010025989-001
*
25mm min.
14
13
1
0010025990-001
13
14
10
500mm min.
25mm min.
400mm
min.
1
9
10
12
11
9

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Worcester Commercial Boiler Series – 6720814332 (2019/04)
Fig. 19 Condensate pump to external disposal
[1] Condensate discharge from boiler
[7] Condensate pump
[13] Insulate and increase pipe size
[14] Pipe work transition
[*] Condensate trap of 75mm already incorporated into the boiler
3.6 Pressure relief pipe work
NOTICE:
 The pressure relief valve is a safety device for the boiler and if
activated may discharge boiling water or steam through the relief
valve drain pipe.
 Care should be taken when siting the outlet pipe so that it does not
cause an obstruction or discharge above a window, entrance or other
public access where it could cause a hazard.
• The pressure relief drain pipe (1) from the boiler should be the same
diameter as the outlet of the safety valve, copper pipe, and run
downwards, away from any electrical equipment or other hazard,
preferably to an external drain or soak away.
• In domestic installations pressure relief drain pipe (1) should be
finished with a partial bend, near the outlet to face the external wall
(as shown) to help prevent freezing.
• In commercial installations an internal drain in the plant room can be
used for both the pressure relief and condensate discharge.
Fig. 20 Pressure relief pipe work
[1] Drain pipe
[2] Outside wall
[3] Drain pipe
[4] External drain
Combined PRV and condensate
The PRV and condensate discharge can be combined by the installer on
the 50kW and 65kW models only according to BS 6798. However, care
must be taken to ensure that an air gap is present between the PRV
discharge pipe and the connection to the condensate discharge pipe.
This is to guard against any potential blockage of the PRV, for example,
frozen condensate.
If the system pressure exceeds the maximum pressure this will result in
the volume of water being discharged through the PRV to be greater than
the storage capacity of condensate pumps.
DO NOT fit a condensate pump when combining the PRV and
condensate.
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25mm min.
14 13
1
7
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3.7 Boiler location and clearances
3.7.1 Installation and servicing clearances
Fig. 21 Clearances [mm]
3.7.2 Compartments
Follow the requirements of BS6798 and BS5440 Part 2 and note:
• Minimum clearances must be maintained.
• If fitting the appliance into an airing cupboard use a non-combustible
material to separate the appliance from the airing space. The material
can be perforated up to a maximum hole size of 13mm.
• An access door is required to install, service and maintain the
appliance and any ancillary equipment.
3.7.3 Bathrooms
If the boiler is fitted in bathrooms, additional RCD (Residual Current
Device) protection may be required.
Consult the latest version of BS7671 (IEE wiring regulations).
3.8 Flue options
CAUTION:
in domestic installations
 Where a flue system is not going to be accessible, provision must be
made for service and inspection.
 Voids containing concealed flues must have at least one inspection
hatch no less than 300mm square.
 Flue joints within the void must not be more than 1.5metres from the
edge of the inspection hatch.
 Inspection hatches should be located at changes of direction.
 If this is not possible, bends should be viewable from both directions.
Groups of appliances with net input in excess of 333kW must comply
with the Clean Air Act by application to the Local Building control
department for flue termination approval. Horizontal terminations above
333kW net input are not permitted (IGE/UP/10 latest edition for full
guidance.)
Horizontal terminations above 70kW net input must comply with the risk
assessment appendix 9 of IGE/UP/10 as well as the general
requirements of IGE/UP/10.
3.8.1 Air supply and flue gas exhaust in a room sealed installation
A ventilation cover is integrated into the boilers. This cover houses a
number of components, such as the burner and the heat exchanger.
Since this ventilation cover is part of the air supply system, it is vital that
it is always installed correctly.
To ensure optimal operation, the appliances should be connected to a
Worcester horizontal or vertical flue terminal. These terminals have been
developed specifically for Worcester condensing gas boilers and have
been comprehensively tested for trouble free operation when correctly
installed. These boilers are also compatible with third party flues if
required.
Standard horizontal flue pack (fig. 22) for 50-V2 and 65-V2:
• 1: Flue turret 80/125;
• 2: Horizontal flue terminal 80/125;
• 3: Flue finishing kit.
Standard horizontal flue pack (fig. 22) for 85-V2 and 100-V2:
• 1: Flue turret 100/150;
• 2: Horizontal flue terminal 100/150;
• 3: Flue finishing kit.
Fig. 22 Standard horizontal flue pack
0010025993-001
300 300
600
25
25
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Worcester Commercial Boiler Series – 6720814332 (2019/04)
Fig. 23 Side flue and rear flue installation
Standard vertical flue pack (fig. 24) for 50-V2 and 65-V2:
• Concentric vertical flue pipe 80/125;
• Wall clamp.
Standard vertical flue pack (fig. 24) for 85-V2 and 100-V2:
• Concentric vertical flue pipe 100/150;
• Wall clamp.
Fig. 24 Standard vertical flue pack
3.8.2 Maximum Flue length (L)
The maximum pipe length (L) of the flue run is determined by the total
pressure loss of all components in the flue system.
Maximum length of horizontal or vertical extensions for 80/125 and
100/150 flue system (fig. 25 and fig. 26). For flue length see
table 10.
Fig. 25 Vertical flue length
Fig. 26 Horizontal flue length
[A] Distance from centre of flue to inside rear wall
[B] Distance from centre wall bracket to centre of flue elbow
[L] Distance from centre of flue to outside wall
Take the flue pipe clearances into account when installation the
linstallation location.
Maximum wall thickness without extensions is 415mm. Maintain a
minimum side clearance of 25mm (fig. 23).
3.8.3 Additional flue parts
The additional flue parts listed can be ordered from your chosen heating
merchant.
Flue size 100/150 and 80/125
Table 10 Max. flue lengths, incl. wall/roofterminal in metres
0010025995-001
415 mm
25 mm
L
0010025996-001
Model Maximum flue length [m]
concentric flue system
100/150mm 80/125mm
50-V2 20 7.7
65-V2 20 7.7
85-V2 18 -
100-V2 18 -
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B

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Table 11 Reduced flue lengths in metres
The total reduction length must never exceed the maximum flue length.
Weathering slates for 80/125 and 100/150
Flat roof, pitched roof.
3.8.4 Standard 100 mm flue systems
The standard concentric flue system provides for a max.
horizontalstraight length (table 10, subsection 3.8.3). Full
instructions for fitting this flue are in subsection 3.8.5: ” Installation of
the horizontal flue” on page 20.
Important: Any horizontal flue system fitted to a condensing boiler must
be declined towards the appliance at an angle of 53mm per metre length
to prevent condensate dripping from the flue terminal. This means that
the clearance above the appliance must factor in the horizontal flue run
length. See fig. 21 on page 18.
3.8.5 Installation of the horizontal flue
The standard flue is suitable for lengths up to 660mm (fig. 27).
For longer flue runs up to 20.0m for the 100/150 flue system and 7.7m
for the 80/125 flue system, flue extensions are available.
Fig. 27 Installation with horizontal flue kit
[1] maximum length
[2] terminal assembly
[3] 90° flue turret
[4] finishing kit
[5] outer wall
3.8.6 Flue pipe preparation and assembly
Measure the flue length L. Refer to figures 28 and 29.
Fig. 28 Flue length - rear
[A] 152mm
[B] 337.5mm for Ø 80/125mm horizontal flue
339.5mm for Ø 100/150mm horizontal flue
[L] flue length
Fig. 29 Flue length - side
The flue must be inclined from the boiler.
 For connection into the elbow, a minimum length of pipe must be
maintained.
The flue gas pipe (inner pipe) and air intake pipe (outer pipe) must
maintain different lengths:
Air intake = L minus 50mm
Flue gas = L minus 70mm
Mark off the lengths and cut to length. The cuts must be square and
free from burrs.
 Assemble flue system completely. Push the flue fully together.
The slope of the terminal outlet [2] must face downwards.
The assembly will be made easier if a solvent free grease is lightly
applied to the male end of the flue.
Fig. 30 Flue terminal position
Model Reduced flue length [m]1)
1) For every bend or extension the max. flue length (L) has to be reduced by the
corresponding length in m.
concentric flue system
100/150mm
concentric flue system
80/125mm
bend extension bend extension
45° 90° 0.5m 1m 45° 90° 0.5m 1m
50-V2 1.2 2.1 0.5 1.0 0.9 1.9 0.5 1.0
65-V2 1.2 2.1 0.5 1.0 0.9 1.9 0.5 1.0
85-V2 1.2 2.1 0.5 1.0 - - - -
100-V2 1.2 2.1 0.5 1.0 - - - -
0010025999-001
5
4
3
2
1
0010026000-001
A
L
B
0010026001-001
L
0010026002-001
4
3
2
1