A.O. Smith TWI 35-200 Troubleshooting guide

Twister
Condensing Stainless Steel
Water Heater
TWI 35-200/45-200
Installation, User and Service Manual
0313279 / R1.1 0819 / EN

A.O. Smith Water Heaters
Unit B7-B8 Armstong Mall
Southwood Business Park
Farnborough Hampshire
GU14 ONR UK
T : 0870 267 6484
[email protected]
www.aosmith.co.uk
A.O. Smith Europe
De Run 5305
PO Box 70
5500 AB Veldhoven
The Netherlands
Data is subject to change.

Preface
Copyright
Copyright © 2018 A.O. Smith Water Products Company
All rights reserved.
Nothing from this publication may be copied, reproduced and/or published by means of
printing, photocopying or by whatsoever means, without the prior written approval of
A.O. Smith Water Products Company.
A.O. Smith Water Products Company reserves the right to modify specifications in this
manual.
Trademarks
Brand names in this manual are registered trademarks of their respective owners.
Warranty
Refer to the appendix Warranty (see 13.7) for the warranty provisions.
Liability
User
A.O. Smith accepts no liability when the water heater is not used correctly and requires
the user to:
•Read this manual carefully and obey the instructions.
•Ask your installation engineer for advise about the use of the water heater.
•Make sure that the service and maintenance activities are done by a qualified
engineer.
•Store the manual, in good condition, near the water heater.
Installation engineer
A.O. Smith accepts no liability when the water heater is not used correctly and requires
the installation engineer to:
•Read this manual carefully and obey the instructions.
•Make sure that the entire water heater installation complies with the applicable
regulations (on page 4).
•Make sure that the water heater is tested before the installation is taken into use.
•Explain the correct use to the user.
•Notify the user when service and maintenance activities are necessary.
•Make sure that you hand over all applicable manuals.
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Supplier
The Twister water heater is designed in accordance with the applicable regulations. The
water heater is delivered with the CE-marking and all necessary documentation to obey
these regulations. See the compliance section. (on page 4)
A.O. Smith accepts no liability for claims from third parties when:
•The instructions for the correct installation of the water heater are not obeyed.
•The instructions for the correct use of the water heater are not obeyed.
•The water heater did not have maintenance on the correct maintenance interval.
For more information, refer to the General Terms of Sales. These are available on request,
free of charge.
We believe that this manual provides you with accurate and complete descriptions of all
relevant components. If you, nonetheless find errors or inaccuracies in this manual, please
inform A.O. Smith. This helps us to further improve our documentation.
Compliance
To safely produce domestic hot water, the design and construction of the Twister water
heaters is in accordance with:
•the European Regulations 2016/426 on appliances burning gaseous fuels (GAR).
•the European Standard for Gas–fired storage water heaters for the production of
domestic hot water (EN89).
•The European ECO-Design Directive.
•The European Energy Labeling Directive
Refer to the appendix Declaration of conformity.
Regulations
It is law that all gas appliances are installed by competent persons, in accordance with The
Gas Safety (Installation and Use) Regulations 1998. Failure to install appliances
correctly could lead to prosecution. It is in your own interest, and that of safety, to ensure
that this law is complied with. The installation of the equipment MUST be in accordance
with the relevant requirements of the Gas Safety Regulations, Building Regulations,
I.E.E. Regulations and the bylaws of the local water undertaking.
In addition, the installation should follow the relevant guidance offered in the following
documents. It is not practical to list all relevant information due to continuous changes but
emphasis is placed on the following documents, as failure to comply with the guidance
given will almost certainly result in an unsatisfactory installation:
•British Standards (BS)
•Institute of Gas Engineers and Managers (IGEM) Publications
•CIBSE Guides
•Clean Air Act
•H.S.E Guidance
Note
Manufacturer's notes must not be taken in any way as overriding statutory obligations.
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Contact information
If you have any comments or questions, please contact:
A.O. Smith Water Products Company
Adress: PO Box 70
5500 AB Veldhoven
The Netherlands
Telephone: 0870 - AOSMITH (free)
0870 - 267 64 84
General: [phone]
Fax: [phone]
E-mail: [email protected]
Website: www.aosmith.co.uk
In the event of problems with your gas, electricity or water supply connections, contact
your (energy/water) supplier.
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6

About this manual
Scope
This manual gives information about safe and correct use of the water heater and how
installation, maintenance and service activities have to be done correctly. You must obey
the instructions in this manual.
Caution
Read this manual carefully before you start the water heater. It can cause personal injury
and damage to the water heater when you do not read the manual and/or do not obey
the instructions.
The purpose of this manual is to:
•describe the working principles and layout of the water heater
•explain the safety devices
•highlight possible hazards
•describe the use of the water heater
•describe the installation, service and maintenance of the water heater
This manual has two parts:
•An User part that describes the correct usage of the water heater.
•An Installation, Maintenance and Service part, that describes the correct installation
and maintenance procedures.
Target group
The information in this manual applies to three target groups:
•users
•installation engineers
•service and maintenance engineers
The User part is intended for the (end) users. The Installation, Maintenance and Service
part is intended for the installation engineers and the service and maintenance engineers.
Notation conventions
This manual uses the following text conventions:
•Numbers between parentheses e.g. (1), refer to elements in a figure that are
described by the text.
•Buttons are always shown between brackets, for example: [ACCEPT], [BACK].
•Cross-references to sections, tables, figures etc. are underlined and written as (see
"..."). In the digital version, the cross-references function as hyperlinks that can be
used to navigate through the manual by clicking on them. Example: Safety (see 2).
This manual contains the following text styles/symbols for situations that may endanger
users/engineers, cause damage to equipment or need special attention:
Note
A note gives more information on a topic.
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Caution
Obey the caution instructions to prevent damage of the water heater.
Warning
Obey the warning instructions to prevent danger of personal injury, and serious damage
to the water heater.
Document identification
Article number Language Version
0313279 UK 1.1
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Table of Contents
Preface........................................................................................ 3
Copyright.......................................................................... 3
Trademarks....................................................................... 3
Warranty...........................................................................3
Liability.............................................................................3
Compliance....................................................................... 4
Regulations....................................................................... 4
Contact information............................................................ 5
About this manual....................................................................... 7
Scope............................................................................... 7
Target group......................................................................7
Notation conventions.......................................................... 7
Document identification.......................................................8
User part.................................................................. 13
1 Introduction.............................................................................. 15
2 Safety........................................................................................17
3 Interface................................................................................... 19
3.1 Operator interface............................................................ 19
3.1.1 Control Switch..................................................................19
3.1.2 Display............................................................................19
3.1.3 Display buttons................................................................ 20
3.2 Status of the water heater................................................. 21
3.2.1 Operating modes.............................................................. 22
3.2.2 Error conditions................................................................22
4 Use............................................................................................ 23
4.1 Turn on the water heater................................................... 23
4.1.1 Switch to ON mode........................................................... 23
4.1.2 Set the water temperature.................................................23
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4.2 Turn off the water heater................................................... 24
4.2.1 Turn off for a short period.................................................. 24
4.2.2 Isolate from the mains...................................................... 24
4.2.3 Turn off for a long period................................................... 24
Installation, Maintenance and Service part.............. 25
5 Introduction.............................................................................. 27
5.1 About the water heater..................................................... 27
5.2 Working principle..............................................................27
6 Safety........................................................................................29
6.1 Safety instructions............................................................29
6.2 Instructions on the water heater.........................................30
6.3 Safety devices..................................................................31
6.4 Environmental aspects...................................................... 33
6.4.1 Recycling.........................................................................33
6.4.2 Disposal.......................................................................... 33
7 Water heater............................................................................. 35
7.1 Structure of the water heater............................................. 35
8 Installation............................................................................... 37
8.1 Packaging........................................................................37
8.2 Conditions....................................................................... 37
8.2.1 Ambient conditions........................................................... 37
8.2.2 Maximum floor load.......................................................... 37
8.2.3 Water composition............................................................ 37
8.2.4 Working clearances...........................................................38
8.3 Installation diagram..........................................................38
8.4 Water connections............................................................ 39
8.4.1 Cold water connection....................................................... 39
8.4.2 Hot water connection........................................................ 40
8.4.3 Circulation connection....................................................... 40
8.5 Condensate drain............................................................. 40
8.6 Gas connection.................................................................40
8.7 Venting system................................................................ 41
8.7.1 C13/C33 concentric systems.............................................. 43
8.7.2 C13/C33 parallel systems.................................................. 45
8.7.3 C43/C53/C63 systems.......................................................47
8.8 Electrical connections........................................................ 48
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8.8.1 Preparation......................................................................48
8.8.2 Mains power.................................................................... 49
8.8.3 External ON mode switch (optional).................................... 49
8.8.4 Finalization...................................................................... 49
8.9 Commissioning.................................................................49
8.9.1 Filling..............................................................................49
8.9.2 Air pressure differential..................................................... 50
8.9.3 Gas supply pressure..........................................................50
8.9.4 CO2 value........................................................................51
8.9.5 Turn on the water heater................................................... 52
8.10 Decommisioning...............................................................52
8.10.1 Turn off the water heater................................................... 52
8.10.2 Draining.......................................................................... 53
9 Conversion of gas type.............................................................. 55
10 Settings.....................................................................................57
10.1 Display............................................................................57
10.2 Temperatures...................................................................57
10.2.1 Temperatures...................................................................58
10.2.2 Hysteresis....................................................................... 58
10.3 Appliance Status...............................................................59
10.4 Display settings................................................................59
10.4.1 Set the display brightness..................................................59
10.4.2 Set the backlight delay......................................................60
10.4.3 Set the language.............................................................. 60
10.5 Appliance information........................................................61
10.5.1 Use external enable.......................................................... 61
10.5.2 Ignition attempts..............................................................62
10.6 Error history.................................................................... 62
10.7 Error occurrence...............................................................63
10.8 Restore default.................................................................63
10.9 Service menu...................................................................63
10.9.1 Set the service mode........................................................ 64
10.9.2 Set the fan speed............................................................. 65
11 Maintenance.............................................................................. 67
11.1 Performance check........................................................... 67
11.2 Preparation......................................................................68
11.3 Water-side maintenance.................................................... 68
11.3.1 Descale the tank.............................................................. 68
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11.3.2 Clean the condensate drain................................................68
11.4 Gas-side maintenance....................................................... 68
11.4.1 Clean the burner.............................................................. 69
11.4.2 Assemble the burner......................................................... 70
11.4.3 Clean the air inlet filter......................................................70
11.5 Finalization...................................................................... 71
12 Troubleshooting........................................................................ 73
12.1 Errors and warnings..........................................................73
12.1.1 General errors..................................................................73
12.1.2 Displayed errors............................................................... 75
12.1.3 Warnings.........................................................................79
13 Appendices................................................................................81
13.1 Technical details............................................................... 81
13.2 Dimensions......................................................................82
13.3 Gas details...................................................................... 84
13.4 Energy labeling................................................................ 85
13.5 Electrical wiring diagram....................................................86
13.6 Declaration of conformity...................................................87
13.7 Warranty......................................................................... 88
Index........................................................................................ 91
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User part
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1 Introduction
The Twister water heater stores and heats water for sanitary purposes.
Cold water enters the bottom of the tank through the water inlet (1). The heated water
leaves the tank at the top through the hot water outlet (2). To operate the water heater,
the display (3) and control switch (4) are used.
Fig. Twister water heater
3
4
2
1
1. Water inlet
2. Water outlet
3. Display
4. Control switch
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16 User part

2 Safety
A.O. Smith cannot be held responsible for damages or injuries which can be lead back to:
•Failure to follow the instructions provided in this manual.
•Carelessness during use or maintenance of the water heater.
Every user must study the user part of this manual and must follow the instructions in this
part of the manual strictly. Do not change the sequence of the described actions. This
manual must be available for the user and service engineer at all times.
Warning
If you smell gas:
•Shut off the mains gas supply valve!
•Avoid causing sparks! Do not use any electrical equipment or switch, i.e.
no telephones, plugs or bells!
•No naked flames! No smoking!
•Open windows and doors!
•Warn occupants and leave the building!
•After leaving the building, alert the gas distribution company or your
installation engineer.
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Caution
Do not store or use chemical substances in the room where the water heater is installed
because of the risk of explosion and corrosion of the water heater. Some propellants,
bleaching agents and degreasing agents etc. disperse of explosive vapors and/or cause
accelerated corrosion. If the water heater is used in a room where such substances are
stored or used, the warranty will be void.
Caution
Installation, maintenance and service may only by carried out by a qualified engineer.
Caution
The water heater is not intended for use by persons with reduced physical, sensory or
mental capacities, or who lack the necessary experience or knowledge. When the person
responsible for their safety is supervising or has explained how the water heater should
be used, these persons can use the water heater.
Caution
This water heater is not intended to be used by children. Always supervise children, and
make sure that they do not play with the water heater.
Note
Regular maintenance extends the service life of the water heater. To determine the
correct service interval, the service and maintenance engineer must do a check on both
the water and gas side of the water heater three months after installation. Based on this
check, the best service interval can be determined.
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18 User part

3 Interface
3.1 Operator interface
The operator interface consists of:
•a control switch (see 3.1.1) on the front side of the water heater, between the doors.
•a (touchscreen) display (see 3.1.2) to navigate through the menu and on which
settings, functions, values and errors can be viewed and entered.
The display is completely menu-driven and enables the user to change settings and to
verify the status and history of the water heater
.
3.1.1 Control Switch
With the control switch you can turn the water heater on I or off 0.
Warning
The power of the water heater stays on when the control switch is set to 0.
3.1.2 Display
The display can show two different types of screens:
•A home screen that shows texts and symbols to indicate the actual status of the
water heater.
•A control screen where more information of the the water heater is shown and where
you can change settings.
Fig. Display - Home screen
1. Title bar
2. Status screen
3. Status bar
4. Control bar
5. Settings screen
Fig. Display - Control screen
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3.1.2.1 Symbols on the display
The symbols on the display give visual information about the status of the water heater.
Symbol Explanation
Water heating is disabled
End of water heating
(stand-by)
Water temperature drops
(during water heating and when in stand-by)
Water temperature rises
(during water heating and when in stand-by)
There is a heat demand
(Pre- and post-) purge
Air pressure switch is closed
A flame is detected
Gas control valve is open
Spark plug is activated / enabled
Error
Warning
3.1.3 Display buttons
With the buttons on the display, the menu of the water heater can be accessed.
Button Function
[MENU] Go to menu
[BACK] One step back in menu. Changed settings will
not be saved
[ACCEPT] Save changed settings
[ ] Value up
[ ] Value down
[>] Enter the submenu
20 User part