Vaillant ecoTEC plus VUI Series User manual

en Installation and maintenance instructions
ecoTEC plus
VUI ..
0020308121_04 - 31.05.2023

2Installation and maintenance instructions 0020308121_04
Installation and maintenance
instructions
Contents
1 Safety .................................................................... 4
1.1 Intended use .......................................................... 4
1.2 Qualification ........................................................... 4
1.3 General safety information .................................... 4
1.4 Regulations (directives, laws, standards) .............. 6
1.5 List of relevant standards for Great Britain and
Ireland.................................................................... 6
2 Guarantee and Customer Service...................... 7
3 Technical data...................................................... 8
4 Notes on the documentation ............................ 10
5 Product description........................................... 10
5.1 CE marking .......................................................... 10
5.2 UKCA mark.......................................................... 10
5.3 Hot Water Association ......................................... 10
5.4 Water Regulations Advisory Scheme .................. 10
5.5 Data plate ............................................................ 10
5.6 Serial number ...................................................... 11
5.7 Sitherm Pro™ technology.................................... 11
5.8 Display of the energy consumption, energy
yields and efficiencies.......................................... 11
5.9 Product design..................................................... 11
5.10 Design of the product's hydraulic block ............... 12
5.11 Design of the product's shift-load cylinder........... 12
5.12 Safety Devices..................................................... 12
6 Set-up.................................................................. 12
6.1 Checking the scope of delivery............................ 12
6.2 Product dimensions ............................................. 13
6.3 Installation site ..................................................... 13
6.4 Minimum clearances............................................ 13
6.5 Compartment Ventilation ..................................... 14
6.6 Using the mounting template............................... 14
6.7 Wall-mounting the product................................... 14
7 Installation.......................................................... 14
7.1 Prerequisites........................................................ 14
7.2 Installing the air/flue pipe..................................... 16
7.3 Installing the gas connection ............................... 20
7.4 Installing pipe connections between the shift-
load cylinder and the heat generator ................... 21
7.5 Installing the hot and cold water connection........ 21
7.6 Installing the heating flow and heating return ...... 22
7.7 Installing the condensate discharge .................... 22
7.8 Installing the drain pipe on the expansion relief
valve .................................................................... 24
7.9 Connecting the flexible hose to the expansion
relief valve on the shift-load cylinder ................... 24
7.10 Electrical installation ............................................ 25
7.11 Installing the front casing..................................... 31
8 Operation............................................................ 32
8.1 Operating concept ............................................... 32
8.2 Calling up the installer level................................. 32
8.3 Calling up/setting diagnostics codes ................... 32
8.4 Running a check programme .............................. 32
8.5 Carrying out the actuator test .............................. 32
8.6 Calling up the data overview ............................... 32
8.7 Calling up status codes........................................ 32
8.8 Exiting the menu level.......................................... 32
8.9 Running the chimney sweep mode
(combustion analysis).......................................... 32
8.10 Switching on the button lock (Advanced Key
Lock) .................................................................... 33
9 Start-up ............................................................... 33
9.1 Pre-Commissioning checklist .............................. 33
9.2 Carrying out the initial start-up............................. 34
9.3 Checking and treating the heating water/filling
and supplementary water .................................... 34
9.4 Deactivating standby mode ................................. 35
9.5 Running through the installation assistant........... 35
9.6 Check programmes and actuator tests................ 35
9.7 Guaranteeing the system pressure ..................... 35
9.8 Flushing the heating installation for the first
time ("cold") ......................................................... 36
9.9 Filling the heating installation .............................. 36
9.10 Purging the heating installation ........................... 36
9.11 Filling and purging the domestic hot water
system ................................................................. 36
9.12 Filling the condensate siphon .............................. 37
9.13 Checking the gas settings ................................... 37
9.14 Thoroughly flushing the heating installation
("hot")................................................................... 40
9.15 Checking the heating mode................................. 40
9.16 Checking the domestic hot water generation ...... 40
9.17 Checking leak-tightness ...................................... 40
10 Adapting the unit to the installation ................ 40
10.1 Setting parameters .............................................. 40
10.2 Activating an additional component for the
multi-functional module........................................ 41
10.3 Adapting the heating settings .............................. 41
10.4 Adapting the domestic hot water settings............ 44
10.5 Displaying the product information ...................... 45
11 Handing over to the end user........................... 45
12 Inspection and maintenance ............................ 45
12.1 Complete Service Interval Record section .......... 45
12.2 Using original seals.............................................. 45
12.3 Maintenance interval............................................ 45
12.4 Actuator test......................................................... 46
12.5 Inspection and maintenance................................ 46
12.6 Preparing the maintenance work......................... 46
12.7 Removing/installing the compact thermal
module ................................................................. 46
12.8 Cleaning/checking the components..................... 48
12.9 Draining the product ............................................ 50
12.10 Completing inspection and maintenance work .... 50
13 Troubleshooting ................................................ 50
13.1 Checking the data overview ................................ 50
13.2 Service messages ............................................... 51
13.3 Fault messages ................................................... 51

0020308121_04 Installation and maintenance instructions 3
13.4 Limp home mode messages ............................... 51
13.5 Resetting parameters to factory settings ............. 51
13.6 Eliminating faults in the product........................... 51
13.7 Replacing defective components......................... 52
14 Decommissioning.............................................. 61
14.1 Activate the standby mode .................................. 61
14.2 Temporarily decommissioning............................. 61
14.3 Permanently decommissioning............................ 61
15 Disposing of the packaging.............................. 61
Appendix ............................................................................ 62
A Tightening torques ............................................ 62
B Inspection and maintenance work................... 62
C Installer level ...................................................... 64
D Diagnostics codes ............................................. 65
E Status codes ...................................................... 72
F Fault codes......................................................... 73
G Check programmes ........................................... 84
H Actuator test....................................................... 84
I Maintenance codes............................................ 85
J Reversible limp home mode codes ................. 85
K Irreversible limp home mode codes ................ 85
L Wiring diagram................................................... 88
M Commissioning Checklist................................. 91
N Commissioning Flow Chart .............................. 95
Index ................................................................................... 96

4Installation and maintenance instructions 0020308121_04
1 Safety
1.1 Intended use
The product is intended as a heat generator
for sealed heating installations and for do-
mestic hot water generation.
Improper use of any kind is prohibited.
Intended use also includes the following:
–use of the product only in mobile homes
that are made, transported once and per-
manently situated in Great Britain and Ire-
land. After the transportation of the mo-
bile home to its destination the complete
product must be checked for leak-tightness
again
–validity of the product only for Great Britain
and Ireland and for the gas types in Great
Britain and Ireland as listed on the data
plate
–Installing and operating the product only
in conjunction with accessories for the
air/flue pipe which are listed in the other
applicable documents and comply with the
type of unit
–Using the product while observing the ac-
companying operating, installation and
maintenance instructions for the product
along with all other components of the in-
stallation
–Installing and setting up the product while
observing the product and system ap-
proval
–Observing all inspection and maintenance
conditions listed in the instructions
–Installing while observing the IP code
The following is classed as improper use:
–Using the product in vehicles, such
caravans. Units that are not classed as
vehicles are those that are installed in a
fixed and permanent location (known as
"fixed installation").
–Using the product in combination with dir-
ectly connected wall-hung domestic hot
water cylinders, whether in the case of a
replacement or for a new installation.
–Using the product for a multiple-flue config-
uration or as a cascade
–Any direct use in industrial or commercial
processes
–Any use other than those described in
these instructions and any use that goes
beyond what is described here
1.2 Qualification
The person carrying out the work described
here must have completed professional train-
ing. The competent person must demon-
strably have all of the knowledge, skills and
capabilities that are required in order to carry
out the work mentioned below.
The following work must only be carried out
by competent persons who are sufficiently
qualified to do so:
–Set-up
–Dismantling
–Installation
–Start-up
–Inspection and maintenance
–Repair
–Decommissioning
▶Proceed in accordance with current tech-
nology.
▶Use the correct tool.
The above-mentioned work must always only
be carried out by persons with sufficient qual-
ifications.
This product can be used by children aged
from 8 years and persons with reduced phys-
ical, sensory or mental capabilities or lack of
experience and knowledge if they have been
given supervision or instruction concerning
use of the product in a safe way and under-
stand the hazards involved. Children must
not play with the product. Cleaning and user
maintenance work must not be carried out by
children unless they are supervised.
1.3 General safety information
The following sections convey important
safety information. It is essential to read and
observe this information in order to prevent
risk of death, risk of injury, material damage
or environmental damage.
1.3.1 Gas
If you smell gas:
▶Avoid rooms that smell of gas.
▶If possible, open doors and windows fully
and ensure adequate ventilation.

0020308121_04 Installation and maintenance instructions 5
▶Do not use naked flames (e.g. lighters,
matches).
▶Do not smoke.
▶Do not use any electrical switches, mains
plugs, doorbells, telephones or other com-
munication systems in the building.
▶Close the emergency control valve or the
main isolator.
▶If possible, close the gas stopcock on the
product.
▶Warn other occupants in the building by
yelling or banging on doors or walls.
▶Leave the building immediately and ensure
that others do not enter the building.
▶Alert the police and fire brigade, and in-
form the emergency service department of
the gas supply company as soon as you
are outside the building.
1.3.2 Flue gas
Flue gases may cause poisoning, while hot
flue gases may also cause burns. Flue gases
must therefore never be allowed to escape
uncontrollably.
What to do if you smell flue gas in the prop-
erty:
▶Open all accessible doors and windows
fully to provide ventilation.
▶Switch off the product.
▶Check the flue gas routes in the product
and the flue gas diversions.
To prevent flue gas exit:
▶Only operate the product if the air/flue pipe
has been completely installed.
▶With the exception of short periods for
testing purposes, only operate the product
when the front casing is installed and
closed.
▶In order to operate the product, ensure that
the condensate siphon is always full.
–Water seal level for units with condens-
ate siphon (third-party accessory):
≥200 mm
To ensure that the seals are not damaged:
▶Instead of grease, use only water or com-
mercially available soft soap to aid installa-
tion.
1.3.3 Air supply
Unsuitable or insufficient combustion and
room air may lead to material damage, but
also to life-threatening situations.
▶Use the data plate, to check the unit types
(air/flue gas) for which the product is ap-
proved:
–Unit type B = open-flued combustion
air supply
–Unit type C = room-sealed combustion
air supply
▶If the product has the approval for unit type
Band you want to operate the product as
open-flued, ensure that the air supply to
the product's installation room is perman-
ently unobstructed and sufficient in accord-
ance with the relevant ventilation require-
ments. This also applies, in particular, for
cupboard installations.
To prevent corrosion on the product and in
the flue system:
▶Ensure that the combustion air supply is
free from sprays, solvents, chlorinated
cleaning agents, paint, adhesives, am-
monia compounds, dust or similar sub-
stances.
▶Ensure that no chemical substances are
stored at the installation site.
▶If you are installing the product in
hairdressing salons, painter's or joiner's
workshops, cleaning businesses or similar
locations, choose a separate installation
room in which the room air is technically
free of chemical substances.
1.3.4 Air/flue pipe
The heat generators are system-certified
together with the original air/flue pipes.
▶Only use original air/flue pipes from the
manufacturer.
1.3.5 Electricity
The power supply terminals L and N remain
live.
To prevent electric shocks, proceed as fol-
lows before working on the product:
▶Disconnect the product from the power
supply by switching off all power supplies
at all poles (electrical partition with a con-
tact gap of at least 3 mm, e.g. fuse or cir-

6Installation and maintenance instructions 0020308121_04
cuit breaker) or remove the mains plug (if
present).
▶Secure against being switched back on
again.
▶Wait at least three minutes until the con-
densers have discharged.
▶Check that there is no voltage.
1.3.6 Weight
To prevent injuries when transporting the
product:
▶Make sure that the product is transported
by at least two people.
To prevent material damage to the flexible
gas pipe:
▶Never suspend the compact thermal
module on the flexible gas pipe.
1.3.7 Explosive and flammable substances
To prevent explosions and fire:
▶Do not use the product in rooms that con-
tain explosive or flammable substances
(such as petrol, paper or paint).
1.3.8 High temperatures
High temperatures may occur in the product
and its immediate vicinity, and may lead to
burns.
To prevent burns:
▶Always ensure that no high temperatures
are present, and only work on components
once they have cooled down sufficiently.
To prevent material damage that is caused
by heat transfer, particularly during soldering
work:
▶Before carrying out soldering work, remove
all sealing materials.
▶Separate components which may be in-
ternally damaged by heat from each other.
▶Only continue the installation processes
once all components have cooled down
(warm to the touch).
1.3.9 Heating water
Both unsuitable heating water and air in the
heating water may cause material damage to
the product and in the heat generator circuit.
▶Check the quality of the heating water.
(→Section 9.3)
▶If you use non-diffusion-tight plastic pipes
in the heating installation, ensure that no
air gets into the heat generator circuit.
1.3.10 Neutralisation device
To prevent contamination of the waste water:
▶Check whether a neutralising unit must
be installed in accordance with national
regulations.
▶Observe local regulations on neutralising
condensate.
1.3.11 Frost
To prevent material damage:
▶Do not install the product in rooms prone
to frost.
1.3.12 Safety devices
▶Install the necessary safety devices in the
installation.
1.4 Regulations (directives, laws,
standards)
▶Observe the national regulations, stand-
ards, directives, ordinances and laws.
1.5 List of relevant standards for Great
Britain and Ireland
▶Observe the national regulations, stand-
ards, directives, ordinances and laws.
You can find a list of relevant standards at:
https://www.vaillant.co.uk/standards

0020308121_04 Installation and maintenance instructions 7
2 Guarantee and Customer Service
Thank you for installing a new Vaillant appliance in your home.
Vaillant appliances are manufactured to the very highest standard so we are pleased to offer our
customers a comprehensive guarantee.
To maintain your guarantee, the boiler must be serviced annually by a competent person who
holds the required qualifications in accordance with the rules in force of the country where the
product is installed and in accordance with the manufactures recommendations.
We recommend you complete your guarantee registration as soon as possible.
Guarantee Registration
Sales Support:
Telephone: [phone]
Technical Enquiries:
Telephone: [phone]
Email: [e-mail]
General Enquiries:
Telephone: [phone]
Training Enquiries:
Telephone: [phone]
Email: [e-mail]
Spares Enquiries:
Telephone: [phone]
To register your Vaillant appliance visit:
https://self-service.vaillant.co.uk/warranty-registration
Vaillant is a licensed member of the Benchmark Scheme. 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 a competent person approved at the time by the Health and
Safety Executive 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 Hotwater Industry Council who manage and promote the Scheme.
Benchmark is managed and promoted by the Heating and Hotwater Industry Council.

8Installation and maintenance instructions 0020308121_04
3 Technical data
Technical data –General
VUI 30/40
Designated country (designation in accordance
with ISO 3166)
GB, IE
Permitted gas boiler category (depending on the
unit version)
I2H
CE PIN 0063CU3910
UKCA PIN 0063CU3910
Gas connection, boiler side 15 mm
Flow/return heating connections, boiler side G 3/4 ″
Domestic hot/cold water connections, boiler side G 3/4″
Expansion relief valve connection 15 mm
Condensate discharge hose connection 19 mm
Air/flue pipe connection 60/100 mm
Capacity of the heating expansion vessel 10 l
Pre-charge pressure of the heating expansion
vessel
70 kPa
(700 mbar)
DHW expansion vessel capacity 1.0 l
DHW expansion vessel pre-charge pressure 400 kPa
(4,000 mbar)
Min. flue gas temperature 35 ℃
Max. flue gas temperature 85 ℃
Approved gas boiler types C13, C33, C43, C53
NOx class 6
SAP 2009/2012 annual efficiency (%) –
Weight with packaging (incl. accessories) 66 kg
Weight (without packaging, without water) 60 kg
Weight, when unit is ready for operation 84 kg
Technical data –G20 output/heat input (depending on the unit version)
VUI 30/40
Gas connection pressure, G20 natural gas 2.0 kPa
(20.0 mbar)
NOx emission, weighted, G20 (EN 15502-2-1) 26.30 mg/kW⋅h
30% efficiency, G20 109.2 %
Gas flow rate for max. gas volume at 15 °C and
1013 mbar, G20
4.32 m³/h
Nominal heat output range at 40/30 °C 5.2 to 32.9 kW
Nominal heat output range at 50/30 °C 5.0 to 32.3 kW
Nominal heat output range at 60/40 °C 4.8 to 31.2 kW
Nominal heat output range at 80/60 °C 4.5 to 29.8 kW
Max. heat input for heating 30.6 kW
Heating min. heat input 4.8 kW
Min. flue gas mass flow rate 2.22 g/s
Max. flue gas mass flow rate 20.55 g/s
Max. DHW heat output –
Domestic hot water nominal heat input 40.8 kW
Nominal heat input range for heating 4.8 to 30.6 kW
Heating adjustment range 4.8 to 30.6 kW

0020308121_04 Installation and maintenance instructions 9
Technical data –Heating
VUI 30/40
Max. flow temperature 85 ℃
Flow temperature adjustment range (factory set-
ting: 75 °C)
30 to 80 ℃
Permissible operating pressure 0.25 MPa
(2.50 bar)
Nominal circulation water volume based on
ΔT = 20 K, 80/60 °C
1,318 l/h
Approx. condensate rate (pH value 3.5 to 4.0) in
50/30 °C heating mode
3.1 l/h
Remaining pump head at nominal circulation
water volume
0.025 MPa
(0.250 bar)
Technical data –Domestic hot water
VUI 30/40
Start-up flow rate 1.8 l/min
Specific flow rate D (ΔT = 30 K) (EN 13203-1) 21.0 l/min
Flow rate (ΔT = 35 K) 18.0 l/min
Permissible operating pressure 0.95 MPa
(9.50 bar)
Required connection pressure 0.07 MPa
(0.70 bar)
Domestic hot water temperature adjustment
range
35 to 65 ℃
Flow rate limiter 14 l/min
Classification in accordance with the total com-
fort factor (EN 13203-1)
***
Cylinder capacity 15.0 l
Technical data –Electrics
VUI 30/40
Nominal voltage/mains frequency 230 V/50 Hz
Permissible connected voltage 190 to 253 V
Built-in fuse (slow-blow) 4 A
Max. electrical power consumption for heating
mode
98.5 W
Max. power consumption in domestic hot water
mode
149 W
Electrical standby energy consumption <2W
IP rating IP X5 D

10 Installation and maintenance instructions 0020308121_04
4 Notes on the documentation
▶Always observe all the operating and installation instruc-
tions included with the system components.
▶Pass these instructions and all other applicable docu-
ments on to the end user.
These instructions apply for the following products only:
Product article number
VUI 30/40 0010036114
Gas Council Numbers
VUI 30/40CS/1-5 (N-GB) ecoTEC plus 940 47-044-96
These instructions apply only to:
–Great Britain
–Ireland
5 Product description
5.1 CE marking
The CE marking shows that the products comply with the
basic requirements of the applicable directives as stated on
the declaration of conformity.
The declaration of conformity can be viewed at the manufac-
turer's site.
5.2 UKCA mark
The UKCA marking shows that the products comply with the
basic requirements of the applicable directives as stated on
the declaration of conformity.
The declaration of conformity can be viewed at the manufac-
turer's site.
5.3 Hot Water Association
Vaillant is a full member of the Hot Water Association and
promotes the scheme in association with its cylinder range.
Details are available on the web site www.vaillant.co.uk
5.4 Water Regulations Advisory Scheme
The product meets the requirements of this quality standard.
5.5 Data plate
2
1
Two data plates are attached to the product at the factory.
The data plate on the top of the unit (2) is always accessible
and contains the basic information for the chimney sweep.
The main data plate (1) with all of the information is attached
to the rear of the electronics box. Any information that is not
listed here can be found in separate sections.
Information Meaning
Read the instructions.
VCI, VUI, VMI, VHR
I
Product with integrated domestic hot
water generation
10 - 36 Nominal heat output
C Condensing boiler
S Stainless steel heat exchanger
/1 Product generation
-5 Product equipment
N, E Gas group
E.g. AT, BE, CH,
DE, DK, ES, FR, IT,
NL, NO, PL, SE
Target market
ecoTEC plus Marketing name
E.g. I2N, 2N, I2ELw,
I2H, G20 –20 mbar
(2.0 kPa)
E.g. I3P, G31 –
50 mbar (5.0 kPa)
Gas group and gas connection pressure
as set at the factory
Cat. Gas boiler category
Type Unit types

0020308121_04 Installation and maintenance instructions 11
Information Meaning
PMS Permissible operating pressure, heating
mode
Pnw Maximum output power
PMW Permissible operating pressure for do-
mestic hot water mode
D Specific domestic hot water flow rate
value
DSN Device specific number
NOx-class NOx class (nitrogen oxide emissions)
Tmax Maximum flow temperature
V Mains voltage
Hz Mains frequency
W Maximum electrical power consumption
IP IP rating
Heating mode
DHW mode
PnNominal heat output range (80/60 °C)
Pnc Condensing nominal heat output range
(50/30 °C)
QnHeat input range
Qnw Heat input range for domestic hot water
generation
Barcode with serial number
3rd to 6th digits = production date
(year/week)
7th to 16th digit = product article number
5.6 Serial number
The serial numbers are located on the underside of the front
panel and on the data plate.
5.7 Sitherm Pro™ technology
The intelligent combustion regulation is based on the adapt-
ive Siemens Sitherm Pro™ combustion optimisation.
5.8 Display of the energy consumption, energy
yields and efficiencies
Note
When replacing the PCB, the values recorded up
to that point are completely reset in the product
and system control.
The product, the system control and the app show approx-
imate values for energy consumption, energy yields and ef-
ficiencies, which are extrapolated based on calculation al-
gorithms.
The values that are displayed in the app may differ from the
other display options due to staggered transfer intervals.
The determined values depend on:
–Installation and system of the heating installation
–User behaviour
–Seasonal weather effects
–Various tolerances of unit-internal components
The values can be read in the following time forms:
–Today
–Yesterday
–Last month
–Last year
–Total
The recording of the values only includes the product in the
factory-delivered condition. Supplementary accessories,
even if they are installed on the product, as well as any other
components in the heating system and other external con-
sumers, are not part of the data recording.
Deviations between the determined values and the actual
values may be significant. The determined values are there-
fore not suitable for creating or comparing energy billing, for
example.
5.9 Product design
14
13
3
4
5
8
7
9
11
10
12
12
6
1 Connection for the
air/flue pipe
2 Flue gas analysis point
3 Expansion vessel
4 Electronics box
5 Hydraulic block
6 Fan
7 Gas valve assembly
8 Compact thermal
module
9 Control electrode
10 Heat exchanger
11 Ignition electrode
12 Air intake pipe
13 Temperature sensor
14 Water pressure sensor

12 Installation and maintenance instructions 0020308121_04
5.10 Design of the product's hydraulic block
2 4 5
7
6
9
8
1
10
3
1 Secondary heat ex-
changer
2 Plug
Hydraulic block without
impeller water flow
sensor (-> Design of
the shift-load cylinder)
3 Strainer at the cold
water inlet
Hydraulic block without
flow rate limiter
4 Prioritising diverter
valve
5 Purging hose
6 Condensate siphon
7 Manometer
8 High-efficiency pump
9 Expansion relief valve
10 Connectivity Interface
Module
5.11 Design of the product's shift-load cylinder
6
4
3
7
8
5
2 1
1 Cylinder charging pump
2 Impeller sensor
3 Temperature sensor at
the domestic hot water
cylinder's outlet
4 Temperature sensor at
the domestic hot water
cylinder's inlet
5 Expansion relief valve
6 Temperature sensor for
the domestic hot water
cylinder
7 Expansion vessel
8 Shift-load cylinder PCB
5.12 Safety Devices
5.12.1 Electrical Supply Failure
The boiler will not work without an electrical supply. Normal
operation of the boiler should resume when the electrical
supply is restored.
Reset any external controls, to resume normal operation of
the central heating.
If the boiler does not resume normal operation press the
reset button. If the boiler does not resume normal operation
after this call your Installation/Servicing company or Vaillant
service.
5.12.2 Overheating Safety
The boiler software is designed to recognise the potential for
an overheat lockout and will shutdown before this happens.
To restart the boiler, press the reset button on the boiler
interface.
If the boiler fails to resume normal operation and all external
controls are calling for heat, then call your Installation/ Servi-
cing company or Vaillant service.
5.12.3 Frost protection
The appliance has a built in frost protection device that pro-
tects the boiler from freezing. With the gas and electric sup-
plies ON and irrespective of any room thermostat setting, the
frost protection device will operate the pump when the tem-
perature of the boiler water falls below 12 °C.
A timer is used so that the temperature can be checked peri-
odically. After 10 minutes the pump will be stopped if the
temperature is higher than 15 °C or has already reached
35 °C. The burner will activate if the boiler temperature does
not reach 15 °C after 30 minutes or at any time if the temper-
ature drops to 5 °C.
The burner will switch off when the temperature reaches
35 °C.
5.12.4 Condensate Drain Blockage
As a safety feature the boiler will stop working if the con-
densate drain becomes blocked. During freezing conditions
this may be due to the forming of ice in the condense drain
external to the house. Release an ice blockage by the use
of warm cloths on the pipe. After pressing reset the boiler
should restart.
6 Set-up
6.1 Checking the scope of delivery
▶Check that the scope of delivery is complete and intact.
Quantity Designation
1Condensing boiler
1 Shift-load cylinder
1 Wall installation set:
1 - Unit mounting bracket
1 - Bag with small parts
1 Shift-load cylinder installation set containing
the following:
2 - Connection pipe (heating flow and return)
1 - Shift-load cylinder-in connection pipe

0020308121_04 Installation and maintenance instructions 13
Quantity Designation
1 - Shift-load cylinder-out connection pipe
1 - Drain hose for the expansion relief valve on
the shift-load cylinder
1- Bag with small parts
1Heat generator installation set containing the
following:
1- Bag with drain pipe and screwed connec-
tion for the expansion relief valve
1 - Gas isolation valve
1 - Gas connection pipe, 15 mm diameter
1 - Domestic hot water connection pipe
1 - Cold water connection pipe, 15 mm dia-
meter
3 - Service valve
2 - Heating flow and return connection pipe,
20 mm diameter
2 Bag with small parts
1 Condensate discharge hose, 1000 mm
1 Manual filling device with Double Check
Valve
1 Mounting template
1 Enclosed documentation
6.2 Product dimensions
B
C
D
A
==
Dimensions
ABCD
VUI 30/40 357 mm 580 mm 440 mm 720 mm
375
325
178
35
100100
35
6.3 Installation site
This boiler is not suitable for outdoor installation. This boiler
may be installed in any room. However if the boiler is being
installed in a room containing a bath or shower it must only
be installed in zones 2 or 3. In GB this is the current I.E.E.
WIRING REGULATIONS and BUILDING REGULATIONS. In
IE reference should be made to the current edition of I.S.813
“Domestic Gas Installations” and the current ETCI rules.
If the boiler is to be installed in a timber frame building it
should be fitted in accordance with the current version of the
Institute of Gas Engineers document IGE/UP/7. If in doubt
seek advice from local building control.
6.4 Minimum clearances
CC
AB
D
Minimum clearance
A 60/100 mm diameter air/flue pipe: 165 or
248 mm. →See mounting template
80/125 mm diameter air/flue pipe: 276 mm
B 180 mm
C 5 mm
D 500 mm in front of the heat generator to enable
easy access for maintenance work (may be
provided by an opening door)

14 Installation and maintenance instructions 0020308121_04
6.5 Compartment Ventilation
The boilers are very high efficiency appliances.
As a consequence the heat loss from the appliance casing
during operation is very low.
Compartment ventilation is not required if the product is fitted
with a concentric flue system.
6.6 Using the mounting template
▶Use the mounting template to set the positions of the drill
holes, wall penetrations and to read all of the required
clearances.
6.7 Wall-mounting the product
1. Ensure that the wall or wall-mounting apparatus (e.g.
individual stands) has a sufficient load-bearing capa-
city.
2. Use approved fixing material to secure the unit mount-
ing bracket.
Note
Use suitable fixing material, in accordance
with the structure of the wall on-site, for a
load-bearing capacity of 100 kg.
The supplied fixing material is suitable only
for walls made from concrete and solid
bricks.
3. Mount the product's shift-load cylinder on the unit
mounting bracket.
4. Mount the product onto the shift-load cylinder's re-
tainer.
7 Installation
7.1 Prerequisites
7.1.1 Gas supply
In the planning phase, consult the local gas supply company
in order to guarantee the availability of sufficient gas sup-
ply. An existing gas supply line must NOT be used without
consulting the local gas supply company first. The product
must only be connected to a gas supply with a regulated gas
meter. A gas meter must only be installed by the local gas
supply company or a registered Gas Safe Engineer. In Ire-
land, it must only be installed by a registered Gas Installer
(RGII).
An existing gas meter should preferably be checked by the
gas supply company in order to ensure that the gas meter is
suitable for supplying the required gas volume. The compet-
ent person is responsible for designing the gas pipelines in
compliance with BS 6891.
If we assume an acceptable pressure loss of 1 mbar for the
gas pipelines to the unit, we can assume a maximum per-
missible operating pressure of 18 mbar at the product's gas
inlet (Reference BS 6400-1 Clause 6.2 Pressure Absorp-
tion).
Use a gas leak-tightness test to ensure that all connections
for the gas valve assembly to the gas control valve are gas-
tight. Gas pipelines must be installed correctly in compliance
with BS 6891. In Ireland, they must be installed in compli-
ance with IS 813. The entire installation MUST be checked
for gas tightness and be purged in accordance with the spe-
cifications in the listed standards.
7.1.2 Using the correct gas type
Operating with a gas type from the incorrect gas family, may
cause fault shutdowns in the product. Ignition and combus-
tion noise may occur in the product.
▶Only use gases from the gas group and gas family that
are specified on the data plate.

0020308121_04 Installation and maintenance instructions 15
7.1.3 Carrying out basic preparation for the
installation
1. Make sure that the existing gas meter is capable of
passing the rate of gas supply required.
2. Consider the maximum heat output given in DHW
mode.
3. Protect the potable water correctly by using a suitable
and approved filling device. Depending on the unit ver-
sion, a filling device is included in the scope of delivery.
4. Install the following components:
–Draining cocks at the lowest points in the heating
installation (→current version of BS 2879)
–A stopcock on the cold water connection
–A stopcock in the gas pipe
5. Install the connection pipes such that they are free
from mechanical stress.
6. If you use non-diffusion-tight plastic pipes in the heat-
ing installation, ensure that no air gets into the heat
generator circuit.
7. Only solder connectors if the connectors are not yet
screwed to the service valves.
8. Only carry out work on components once they have
cooled down.
9. Only bend connection pipes if they have not yet been
connected to the product.
10. Flush the heating installation thoroughly before in-
stalling the product.
11. If, during gas leak-tightness tests, you also place the
gas pipes and the gas valve assembly in the product
under pressure, use a max. test pressure of ≤11 kPa
(110 mbar).
12. If you cannot limit the test pressure to 11 kPa
(110 mbar), close any gas stopcocks that are installed
upstream of the product before you carry out the gas
leak-tightness test.
13. If, during gas leak-tightness tests, you have closed the
gas stopcock that is installed upstream of the product,
relieve the gas line pressure before you open this gas
stopcock.
14. Insulate bare pipes exposed to environmental influ-
ences to protect them from frost using suitable insulat-
ing material.
7.1.4 Pressure maintenance in the heating
installation
Heating installations are sealed systems. Air flows in a sys-
tem's heating circuit are disruptive factors that have negative
effects. To prevent air from getting into the system, excess
pressure is built up against the atmospheric pressure, and
this must be maintained. Excess pressure and temperature
fluctuations in the heating circuit are offset by a diaphragm
expansion vessel.
The product is fitted with a diaphragm expansion vessel.
During the installation, you must check whether the volume
of this diaphragm expansion vessel is sufficient for the heat-
ing installation.
Note
The subsequent check is an approximation
method, which does not replace a detailed
technical design. The result only provides a rough
guide for whether the installed diaphragm expan-
sion vessel with a volume of 10 l is sufficient or
whether an additional external expansion vessel is
required.
The following database is based on the diagram below:
–Pure heating water without added frost protection
–Average temperature 55 °C
–Initial pressure 0.05 MPa (0.5 bar)
–Final pressure 0.25 MPa (2.5 bar)
2
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
46810121416182022242628 30 32 34 36 38 40 B
A
2 3
4
1
A Expansion vessel
volume in l
B Installed heat output in
kW
1 Underfloor heating
2 Radiators made from
pipes or steel
3 Radiators made from
cast iron
4 Nominal volume of the
installed expansion
vessel
▶Determine the following values.
–Installed heat output in kW
–Heating system: Radiators made from cast iron, radi-
ators made of pipes or steel, or underfloor heating
▶Starting from the installed heat output in a vertical line
upwards, determine the intersection point with the curve
for the relevant heating system.
◁If the intersection point lies below the dotted line for
the installed expansion vessel, it may be the case
that no additional external expansion vessel is re-
quired.
◁If the intersection point lies above the dotted line for
the installed expansion vessel, it is probable that an
additional external expansion vessel is required.
▶If an external expansion vessel is required for the correct
pressure maintenance in the heating installation, install it
in the heating return as close as possible to the product.

16 Installation and maintenance instructions 0020308121_04
Condition: External expansion vessel installed and warm start active
▶Install a non-return valve in the product outlet (heating
flow) or decommission the internal expansion vessel in
order to prevent the warm start function from being in-
creasingly activated due to backflow.
7.1.5 Softening water
For hard potable water with a degree of hardness of >15 °dH
(267 ppm CaCO₃; 2.67 mol/m³), it may make sense to soften
or stabilise the water or, in the case of domestic hot water,
this may be necessary in order to protect the potable water
installation.
Scale deposition increases as the water temperature in-
creases.
▶Check whether the potable water may need to be
softened and, if required, soften the water.
▶Use one of the technical options that complies with the
recognised rules of technology.
7.2 Installing the air/flue pipe
7.2.1 Room-sealed air/flue pipe
Note
This product range is only permitted for the C13,
C33, C43 and C53 unit types. Only room-sealed
installation is therefore permitted. Combustion air
supply from the installation room and adjacent
rooms is not permitted. The combustion air must
be supplied from outside of the building.
7.2.2 Regulation
Different flue outlet configurations can be carried out.
–Consult the installation manual for air/flue gas systems
for more information about the other possibilities and
associated accessories.
Minimum fall
44 mm/m
–Standard flue terminal kits have an in-built fall back to
the boiler to drain the condensate. These can be fitted
level between the appliance and the termination position.
All other extended flues must have a fall of at least 44
mm/m.
The maximum length of the flue outlet is defined according to
its type (for example C13).
–Whatever the kind of flue system chosen, observe the
minimum distances to position the flue terminals.
–To install the flue, refer to the separate flue instruction
supplied with your appliance.
–Explain these requirements to the user of the appliance.
In GB the minimum acceptable siting dimensions for the
terminal from obstructions, other terminals and ventilation
openings are shown in diagram overleaf.
In IE the minimum distances for flue terminal positioning
must be those detailed in I.S. 813 “Domestic Gas Installa-
tions”.
The terminal must be exposed to the external air, allowing
free passage of air across it at all times.
Being a condensing boiler some pluming may occur from
the flue outlet. This should be taken into consideration when
selecting the position for the terminal.

0020308121_04 Installation and maintenance instructions 17
7.2.3 Position of the air/flue terminal
J
J
N
Q
S
S
P
UB
Boundary
G
D
J
JR
VM
T
G
C
W
E
F
L
A
K
S
P
S
F
X
A
Y
Boundary
Z
H
Aa
S
Z
Ba
7.2.3.1 Positioning the terminal of a fan-supported flue system
Installation site Dimensions
AAdjacent to a boundary. 300 mm
B1) The dimension below eaves, balconies and car ports can be reduced to this value, as long as the flue terminal is
extended to clear any overhang. External flue joints must be sealed with a suitable silicon sealant. 25 mm
C Between a vertical flue terminal and a window or dormer window on a roof. 1,500 mm
D Between terminals facing each other. 1,200 mm
E Vertical flue clearance, adjacent to a boundary line. 300 mm
F2) Distance to a boundary line, unless it will cause a nuisance. BS 5440:Part 1 recommends that care is taken
when siting terminal in relation to boundary lines. 600 mm
G Minimum clearance from a skylight to a vertical flue or to another vertical flue. Min. 300 mm
HVertical flue clearance, to noncombustible building material.
Vertical flue clearance to combustible building material.
500 mm
1,500 mm
J Above, below and either side of an opening door, air vent or opening window. 300 mm
K Diagonally to an opening door, air vent or opening window. 600 mm
L2) To an internal or external corner. This dimension can be reduced if a plume diverter is used. 200 mm
MBelow a Velux window.
Above or to either side of the Velux window.
2,000 mm
600 mm
NFrom a pitched roof.
In regions with heavy snowfall.
400 mm
500 mm
P From vertical drain pipes and soil pipes. 25 mm
QBelow eaves.
Below gutters, pipe and drains.
200 mm
75 mm
1) There should be no ventilation/opening in the eaves within 300 mm distance of the terminal.
2) These dimensions comply with the building regulations, but they may need to be increased to avoid wall
staining and nuisance from pluming depending on site conditions.
–Terminals must be positioned so to avoid combustion products entering the building.
–Support the flue at approximately one metre intervals and at a change of direction, use suitable brackets and
fixings.
–Installations in car ports are not recommended.
–The flue cannot be lower than 1 metre from the top of a lightwell due to the build up of combustion products.
–Dimensions from a flue terminal to a fanned air inlet to be determined by the ventilation equipment.

18 Installation and maintenance instructions 0020308121_04
Installation site Dimensions
RThe dimension below eaves, balconies and car ports can be reduced to this value, as long as the flue terminal is
extended to clear any overhang. External flue joints must be sealed with suitable silicon sealant. 25 mm
S Above adjacent ground or balcony. 300 mm
T2) Distance to a surface facing a terminal, unless it will cause a nuisance. BS 5440: Part 1 recommends that care
is taken when siting terminals in relation to surfaces facing a terminal.
600 mm
U Clearance alongside another terminal. 300 mm
V Above roof level. 300 mm
W Minimum to vertical structure on roof, roof vent. Min. 300 mm
X Minimum to opening in adjacent building. Min.
2000 mm
Y Minimum at an angle to a boundary which is not less than 300 mm to the terminal Min. 600 mm
Z Minimum measured to the nearest corner of the OPEN window Min. 600 mm
Aa No more than this value above ridge. Max.
300 mm
Ba Not less than this value below the opening window Min. 300 mm
1) There should be no ventilation/opening in the eaves within 300 mm distance of the terminal.
2) These dimensions comply with the building regulations, but they may need to be increased to avoid wall
staining and nuisance from pluming depending on site conditions.
–Terminals must be positioned so to avoid combustion products entering the building.
–Support the flue at approximately one metre intervals and at a change of direction, use suitable brackets and
fixings.
–Installations in car ports are not recommended.
–The flue cannot be lower than 1 metre from the top of a lightwell due to the build up of combustion products.
–Dimensions from a flue terminal to a fanned air inlet to be determined by the ventilation equipment.
7.2.3.2 Horizontal terminal positioning
BS 5440-1 recommends that fanned flue chimney terminals should be positioned as follows:
a) at least 2 m from an opening in the building directly opposite, and
b) so that the products of combustion are not directed to discharge directly across a boundary if the products are likely to
cause a nuisance to a neighbour or discharge over a walkway or patio.
For IE see current issue of IS 813.
For boilers covered within this manual.
Dimensions B and R:
These clearances may be reduced to 25 mm without affecting the performance of the boiler. In order to ensure that the con-
densate plume does not affect adjacent surfaces the terminal should be extended as shown below.
Balcony/eaves
Gutter
Adequately secured
air/flue gas pipe
The flue pipe must
protrude beyond any overhang
You can use a plume management kit to enable the termination point to be positioned and directed away from the building
fabric.

0020308121_04 Installation and maintenance instructions 19
7.2.4 Flue Configuration Description
7.2.4.1 Horizontal Concentric Flue ⌀60/100 mm or
⌀80/125 mm (C13 type installation)
1
1 Gasket (fitted)
Note
If the terminal is at less than 2.0 m from the
ground, you must install a terminal protection kit.
Consult the separate installation manual for air/flue gas sys-
tems supplied with your appliance for all possibilities and as-
sociated accessories and how to install the flue system.
7.2.4.2 Terminal protection
A terminal guard is required if persons could come into con-
tact with the terminal or the terminal could be subject to dam-
age.
If a terminal guard is required, it must be positioned to
provide minimum of 50 mm clearance from any part of the
terminal and be central over the terminal.
The guard should be stainless and similar to that shown in
the figure.
7.2.4.3 Vertical Concentric Flue ⌀60/100 mm or
⌀80/125 mm (C33 type installation)
Consult the separate installation manual for air/flue gas sys-
tems supplied with your appliance for all possibilities and as-
sociated accessories and how to install the flue system.
7.2.5 Installing and connecting the air/flue pipe
1. You can find out which air/flue pipes may be used
by consulting the enclosed set-up instructions for the
air/flue system.
2. Observe the information on positioning the air/flue ter-
minal.
Condition: Installation in damp rooms
▶You must connect the product to a room-sealed air/flue
system. The combustion air must not be taken from the
installation site.
Caution.
Risk of poisoning due to escaping flue
gas.
Mineral-oil-based greases can damage the
seals.
▶Instead of grease, use only water or com-
mercially available soft soap to aid install-
ation.
3. Install the air/flue pipe using the set-up instructions.

20 Installation and maintenance instructions 0020308121_04
7.2.6 Replacing the standard connector for the
air/flue pipe, where required
7.2.6.1 Removing the standard connector for the
air/flue pipe
A
B
C
7.2.6.2 Installing the connector for the air/flue pipe,
60/100 mm or 80/125 mm diameter
1. Remove the standard connector for the air/flue pipe.
(→Section 7.2.6.1)
2. Insert the alternative connector. In doing so, pay atten-
tion to the latching lugs.
3. Turn the standard connector clockwise until it clicks
into position.
7.3 Installing the gas connection
▶Install the gas pipe in accordance with the recognised
rules of technology.
▶Remove the residues from the gas pipe by decoupling on
both sides and blowing through the gas pipe.
▶Use the enclosed gas isolation valve. Observe the spe-
cified flow direction.
Note
Gas isolation valves with or without test nipple
are available in the dimensions 15 to 15 mm
or 22 to 15 mm.
Condition: Gas isolation valve without test nipple
▶Connect the product to the gas pipe as shown in accord-
ance with the recognised rules of good engineering prac-
tice.
Condition: Gas isolation valve with test nipple (requirement for BS 6891)
1
▶Connect the product to the gas pipe as shown in accord-
ance with the recognised rules of good engineering prac-
tice.
▶Always ensure that the test nipple (1) is sealed and is
correctly checked for tightness. Tightening torque, see
appendix.
–Working materials: 3 mm hex key
▶Purge the gas pipe before start-up.
▶Check the entire gas supply for tightness in accordance
with the relevant standards.