A.O. Smith 28 30 50 60 User Manual

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Release R.1.3 UK
28 30 50 60
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Installation
User and
Service Manual
WATER PRODUCTS
COMPANY
A DIVISION OF A. O. SMITH CORPORATION
XTRA HIGH EFFICIENCY
www.aosmithinternational.com
your installer

Copyright

Trademarks

Liability

Warning
Read this manual carefully before first using the water heater. Failure to read this manual and to follow the instructions in this manual may lead to accidents, personal injury, and damage to the appliance.
Copyright 2003 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 stated in this manual.
Any brand names mentioned in this manual are registered trademarks of their respective owners.
A.O. Smith Water Products Company accepts no liability for claims from third parties arising from improper use other than that stated in this manual and in accordance with the General Conditions registered at the Eindhoven Chamber of Commerce.
Refer further to the General Conditions. These are available on request, and without charge.
Although considerable care has been taken to ensure a correct and suitably comprehensive description of all relevant components, the manual may nonetheless contain errors and inaccuracies.
Should you detect any errors or inaccuracies in the manual, we would be grateful to receive notification. This helps us to further improve our documentation.

More information

If you have any comments or queries concerning any aspect related to the appliance, then please do not hesitate to contact A.O. Smith Water Products Company.
A.O. Smith Postbus 70 5500 AB Veldhoven The Netherlands
Freephone: 008008 AOSMITH
008008 2 67 64 84 General: +31 40 294 25 00 Sales: +31 40 294 25 37 Help desk: +31 40 294 25 38 Fax: +31 40 294 25 39
E-mail: info@aosmith.nl Internet: www.aosmithinternational.com
In the event of problems with connecting to the gas, electricity or water supply, please contact your installation’s supplier/installer.
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4 Instruction Manual BFC
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Table of contents

1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
1.1 About the appliance - - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
1.2 What to do if you smell gas- - - - - - - - - - - - - - - - - - - - - - - - - 9
1.3 Regulations - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
1.4 Target groups - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10
1.5 Maintenance - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10
1.6 Forms of notation - - - - - - - - - - - - - - - - - - - - - - - - - - - - 10
1.7 Overview of this document - - - - - - - - - - - - - - - - - - - - - - - - 11
2 Functioning of the appliance - - - - - - - - - - - - - - - - - - 13
2.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 13
2.2 Functional description of the appliance - - - - - - - - - - - - - - - - - - 13
2.3 The appliance’s heating cycle - - - - - - - - - - - - - - - - - - - - - - 14
2.4 Protection for the appliance - - - - - - - - - - - - - - - - - - - - - - - 14
2.4.1 Water temperature protection - - - - - - - - - - - - - - - - - 15
2.4.2 Gas control - - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.4.3 Fan - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
2.4.4 Pressure switch - - - - - - - - - - - - - - - - - - - - - - - - 15
2.4.5 Ionisation rod - - - - - - - - - - - - - - - - - - - - - - - - - 16
2.5 Safety of the installation - - - - - - - - - - - - - - - - - - - - - - - - - 16
2.5.1 Unvented installation - - - - - - - - - - - - - - - - - - - - - 16
2.5.2 Vented installation- - - - - - - - - - - - - - - - - - - - - - - 16
2.5.3 T&P valve - - - - - - - - - - - - - - - - - - - - - - - - - - - 16
3 Installation - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
3.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
3.2 Packaging - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
3.3 Environmental conditions- - - - - - - - - - - - - - - - - - - - - - - - - 17
3.3.1 Humidity and ambient temperature- - - - - - - - - - - - - - - 18
3.3.2 Maximum floor loading - - - - - - - - - - - - - - - - - - - - 18
3.3.3 Water composition - - - - - - - - - - - - - - - - - - - - - - 18
3.3.4 Working clearances - - - - - - - - - - - - - - - - - - - - - - 18
3.4 Technical specifications - - - - - - - - - - - - - - - - - - - - - - - - - 20
3.5 Installation diagram - - - - - - - - - - - - - - - - - - - - - - - - - - - 23
3.6 Water connections, Unvented - - - - - - - - - - - - - - - - - - - - - - 25
3.6.1 Cold water side - - - - - - - - - - - - - - - - - - - - - - - - 25
3.6.2 Hot water side- - - - - - - - - - - - - - - - - - - - - - - - - 25
3.6.3 Circulation pipe - - - - - - - - - - - - - - - - - - - - - - - - 25
3.6.4 Condensation drainage - - - - - - - - - - - - - - - - - - - - 25
3.7 Water connections, Vented- - - - - - - - - - - - - - - - - - - - - - - - 26
3.7.1 Cold water side - - - - - - - - - - - - - - - - - - - - - - - - 26
3.7.2 Hot water side- - - - - - - - - - - - - - - - - - - - - - - - - 26
3.7.3 Circulation pipe - - - - - - - - - - - - - - - - - - - - - - - - 26
3.7.4 Condensation drainage - - - - - - - - - - - - - - - - - - - - 26
3.8 Gas connection - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 26
3.9 Air supply and flue gas discharge- - - - - - - - - - - - - - - - - - - - - 27
3.9.1 Concentric wall flue terminal - - - - - - - - - - - - - - - - - - 28
3.9.2 Concentric roof flue terminal - - - - - - - - - - - - - - - - - - 29
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3.10 Electrical connection - - - - - - - - - - - - - - - - - - - - - - - - - - - 30
3.10.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 30
3.10.2 Preparation- - - - - - - - - - - - - - - - - - - - - - - - - - - 30
3.10.3 Mains voltage - - - - - - - - - - - - - - - - - - - - - - - - - 31
3.10.4 Isolating Transformer - - - - - - - - - - - - - - - - - - - - - - 32
3.10.5 Continuous pump- - - - - - - - - - - - - - - - - - - - - - - - 32
3.10.6 program-controlled pump - - - - - - - - - - - - - - - - - - - - 32
3.10.7 Extra ON mode switch (“Tank ON”) - - - - - - - - - - - - - - - 32
3.10.8 Connecting extra error signal (“Alarm OUT”) - - - - - - - - - - 33
3.11 Checking the supply pressure and burner pressure - - - - - - - - - - - - 33
3.12 Conversion to a different gas category - - - - - - - - - - - - - - - - - - - 35
4 Filling and draining - - - - - - - - - - - - - - - - - - - - - - - 39
4.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 39
4.2 Filling the appliance - - - - - - - - - - - - - - - - - - - - - - - - - - - - 39
4.2.1 Filling unvented installations - - - - - - - - - - - - - - - - - - 39
4.2.2 Filling vented installations- - - - - - - - - - - - - - - - - - - - 39
4.3 Draining the appliance - - - - - - - - - - - - - - - - - - - - - - - - - - 41
4.3.1 Draining unvented installations - - - - - - - - - - - - - - - - - 41
4.3.2 Draining vented installations - - - - - - - - - - - - - - - - - - 41
5 The control panel - - - - - - - - - - - - - - - - - - - - - - - - 43
5.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43
5.2 Operating - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 43
5.3 Explanation of the icons - - - - - - - - - - - - - - - - - - - - - - - - - - 44
5.4 ON/OFF switch of ThermoControl - - - - - - - - - - - - - - - - - - - - - 44
5.5 Navigation buttons - - - - - - - - - - - - - - - - - - - - - - - - - - - - 44
5.6 PC connection. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 44
6 Status of the appliance - - - - - - - - - - - - - - - - - - - - - 45
6.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 45
6.2 Operating modes - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 45
6.3 Error conditions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 46
6.4 Service condition - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 47
7 Starting up and shutting down - - - - - - - - - - - - - - - - - 49
7.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
7.2 Starting up - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
7.3 Shutting down- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 49
7.3.1 Shut the appliance down for a brief period (“OFF mode”) - - - - 50
7.3.2 Disconnect the appliance from the mains - - - - - - - - - - - - 50
7.3.3 Shut the appliance down for a longer period - - - - - - - - - - - 50
7.4 The appliance’s heating cycle - - - - - - - - - - - - - - - - - - - - - - - 51
8 Main menu - - - - - - - - - - - - - - - - - - - - - - - - - - - 53
8.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 53
8.2 Notational convention for menu-related instructions - - - - - - - - - - - - 53
8.3 Switching into “ON mode” - - - - - - - - - - - - - - - - - - - - - - - - - 54
8.4 Setting the water temperature - - - - - - - - - - - - - - - - - - - - - - - 54
8.4.1 Setting the water temperature via SETPOINT MENU - - - - - - 54
8.4.2 Setting water temperature during ON mode - - - - - - - - - - - 54
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8.5 Week programme - - - - - - - - - - - - - - - - - - - - - - - - - - - - 55
8.5.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 55
8.5.2 Starting up and shutting down the week program - - - - - - - - 55
8.5.3 Changing the appliance’s standard week program - - - - - - - 55
8.5.4 Adding times to a week program - - - - - - - - - - - - - - - - 57
8.5.5 Deleting times from a week program - - - - - - - - - - - - - - 58
8.6 Extra period - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 60
8.6.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 60
8.6.2 Programming an extra period - - - - - - - - - - - - - - - - - 60
8.7 Settings - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 61
8.7.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 61
8.7.2 Setting menu language - - - - - - - - - - - - - - - - - - - - 61
8.7.3 Setting day and time- - - - - - - - - - - - - - - - - - - - - - 62
8.7.4 Displaying appliance specifications - - - - - - - - - - - - - - 62
9 Service program - - - - - - - - - - - - - - - - - - - - - - - - 65
9.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 65
9.2 Setting the hysteresis - - - - - - - - - - - - - - - - - - - - - - - - - - 65
9.3 Displaying the error history - - - - - - - - - - - - - - - - - - - - - - - - 65
9.4 Displaying the appliance history - - - - - - - - - - - - - - - - - - - - - 66
9.5 Display the selected appliance - - - - - - - - - - - - - - - - - - - - - - 66
9.6 Setting the pump on/off - - - - - - - - - - - - - - - - - - - - - - - - - 66
9.7 Setting the service interval - - - - - - - - - - - - - - - - - - - - - - - - 66
9.8 Setting the display contrast- - - - - - - - - - - - - - - - - - - - - - - - 67
9.9 Setting the backlight time- - - - - - - - - - - - - - - - - - - - - - - - - 67
9.10 Setting the display scroll speed- - - - - - - - - - - - - - - - - - - - - - 67
10 Troubleshooting - - - - - - - - - - - - - - - - - - - - - - - - 69
10.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 69
10.2 Troubleshooting table for general errors - - - - - - - - - - - - - - - - - 70
10.3 Troubleshooting table for displayed errors - - - - - - - - - - - - - - - - 72
11 Maintenance frequency - - - - - - - - - - - - - - - - - - - - 83
11.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 83
11.2 Determining service interval - - - - - - - - - - - - - - - - - - - - - - - 83
12 Maintenance - - - - - - - - - - - - - - - - - - - - - - - - - - 85
12.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 85
12.2 Preparation for maintenance - - - - - - - - - - - - - - - - - - - - - - - 85
12.3 Water-side maintenance - - - - - - - - - - - - - - - - - - - - - - - - - 87
12.3.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 87
12.3.2 Checking the anodes - - - - - - - - - - - - - - - - - - - - - 87
12.3.3 Descaling and cleaning the tank - - - - - - - - - - - - - - - - 87
12.3.4 Cleaning condensation water discharge - - - - - - - - - - - - 87
12.4 Gas-side maintenance - - - - - - - - - - - - - - - - - - - - - - - - - - 87
12.4.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - 87
12.4.2 Cleaning the burner - - - - - - - - - - - - - - - - - - - - - - 87
12.4.3 Cleaning the orifice - - - - - - - - - - - - - - - - - - - - - - 88
12.4.4 Cleaning heat exchanger - - - - - - - - - - - - - - - - - - - 88
12.5 Finalising maintenance- - - - - - - - - - - - - - - - - - - - - - - - - - 88
13 Warranty (Certificate)- - - - - - - - - - - - - - - - - - - - - - 89
13.1 General warranty - - - - - - - - - - - - - - - - - - - - - - - - - - - - 89
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13.2 Tank warranty- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 89
13.3 Installation and conditions of use - - - - - - - - - - - - - - - - - - - - - 89
13.4 Exclusions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 89
13.5 Scope of the warranty - - - - - - - - - - - - - - - - - - - - - - - - - - - 90
13.6 Claims - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 90
13.7 Limitation of liability A.O. Smith - - - - - - - - - - - - - - - - - - - - - - 90
A Appendices - - - - - - - - - - - - - - - - - - - - - - - - - - - 91
A.1 Introduction - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 91 A.2 Electrical diagram BFC - - - - - - - - - - - - - - - - - - - - - - - - - - 92
IX Index - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 95
8 Instruction Manual BFC

About the appliance

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1 Introduction

1.1 About the appliance This manual describes how to install, service and use the BFC appliance. The
BFC appliance is a condensing room-sealed water heater with a fan in the air intake. A concentric chimney connector is fitted standard to the appliance. Alternatively, the appliance can be connected using a parallel system. Installation types possible with this appliance are C13, C33, C43, C53 and C63. The information in this manual is applicable to types: BFC 28, BFC 30, BFC 50 and BFC 60.
The manner of construction and features of the appliance are in conformance with the European standard for gas-fired storage water heaters for the production of domestic hot water (ES 89). The appliances are therefore compliant with the European Directive for Gas Appliances, and have the right to bear the CE mark.
Warning
0063
Read this manual carefully before starting up the water heater. Failure to read the manual and to follow the printed instructions may lead to personal injury and damage to the appliance.

1.2 What to do if you smell gas

1.3 Regulations As the (end) user, installer or service and maintenance engineer, you must

Warning
Whenever there is a smell of gas:
No naked flames! No smoking!
Avoid causing sparks! Do not use any electrical equipment or switch, i.e. no telephones, plugs or bells!
Shut off the mains gas supply!
Open windows and doors!
Warn occupants and leave the building!
After leaving the building, alert the gas distribution company or installer.
ensure that the entire installation complies, as a minimum, with the official local:
building regulations;
energy supplier’s directives for existing gas installations;
directives and technical guidelines for natural gas installations;
safety requirements for low-voltage installations;
regulations governing the supply of drinking water;
regulations governing ventilation in buildings;
regulations governing the supply of air for combustion;
regulations governing the discharge of products of combustion;
requirements for installations that consume gas;
regulations governing indoor waste water disposal;
regulations imposed by fire service, power companies and municipality;
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Introduction
Furthermore, the installation must comply with the manufacturer’s instructions.
n Remark
Later amendments and/or additions to all regulations, requirements and guidelines published on or prior to the moment of installing, will apply to the installation.

1.4 Target groups The three target groups for this manual are:

(end) users;
•installers;
service and maintenance engineers.
Symbols on each page indicate the target groups for whom the information is intended. See Table 1.1.
Tabl e 1 .1 Target group symbols
Symbol Target group
(End) user
g
installer
i
Service and maintenance engineer
s
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1.5 Maintenance A service should be carried out at least once a year, both on the water side and

on the gas side. Maintenance frequency depends, among other things, on the water quality, the average burning time per day and the set water temperature.
n Remark
To determine the correct maintenance frequency, it is recommended to arrange for the service and maintenance engineer to check the appliance on both the water and gas side, three months after installation. Based on this check, the best maintenance frequency can be determined.
n Remark
Regular maintenance extends the service life of the appliance.

1.6 Forms of notation The following notation is used in this manual:

n Remark
Important information
cNote
Ignoring this information can lead to the appliance being damaged.
Warning
Failure to carefully read this information may lead to danger of personal injury, and serious damage to the appliance.
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Overview of this document

1.7 Overview of this document

Tab le 1. 2 Contents of document
Chapter Target groups Description
2 Functioning of the appliance
3 Installation
4 Filling and draining
Ta bl e 1. 2 provides an overview of the contents of this document.
This chapter describes how the appliance functions.
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This chapter describes the installation activity to be completed
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before you actually start up the appliance.
This chapter describes how to fill and drain the appliance.
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5 The control panel
6 Status of the appliance
7 Starting up and shutting down
8 Main menu
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This chapter describes the general control of the appliance using the display.
This chapter describes the status (mode or condition) that the appliance may have, and possible actions to take.
This chapter describes how to start up the appliance, and how to shut it down for a brief or long period of time. The general heating cycle of the appliance is also described.
Describes the main menu of the display. This is the actual menu for the user, however the installer and service and maintenance engineers will also need to use this menu.
9 Service program
10 Troubleshooting
11 Maintenance frequency
12 Maintenance
13 Warranty (Certificate)
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Describes the service menu. It is mainly intended for the installer and service and maintenance engineers. End users may also refer to this chapter for additional information about the appliance.
This chapter is mainly intended for the installer and the service and maintenance engineer. It describes appliance errors. These errors are indicated on the display. A troubleshooting table of possible causes and solutions is provided. End users may also refer to this chapter for additional information about the appliance.
This chapter describes how to determine the optimum frequency at which to carry out maintenance. Both the end user and the service and maintenance engineer are responsible for regular maintenance. They need to reach clear agreement on this.
n Remark
If the appliance is not regularly maintained, the warranty will become void.
This chapter sets out the maintenance tasks to be carried out during a service.
This chapter states the warranty terms and conditions.
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Introduction
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a
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2 Functioning of the
appliance
2.1 Introduction Topics covered in this chapter:
Functional description of the appliance;
The appliance’s heating cycle;
Protection for the appliance;
Safety of the installation.

Introduction

2.2 Functional description of the appliance

Legend
a plastic top cover
b hot water outlet
c electrical connection block
d ThermoControl
e pressure switch
f control panel
g temperature sensor T
h combustion chamber
i anode
j tank
k heat exchanger
l inspection and cleaning
opening
m temperature sensor T
n cold water inlet
o drain valve
p gas control
q burner
r fan
s air supply hose
t glow igniter
u ionisation rod
v chimney pipe
w siphon
x PU insulation layer
1
2
Figure 2.1 shows a cut-away view of the appliance.
b
c
d
e
f
g
h
i
j
k
l
m
n
o
p
q
r
s
t
u
v
w
x
IMD-0070
Figure 2.1 Cut-away view of the appliance
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Functioning of the appliance
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In this appliance the cold water enters the bottom of the tank via the cold water inlet n. The tap water, heated by the combustion chamber h and heat exchanger k, leaves the tank through the hot water outlet b. Once the appliance is completely filled with water, it remains constantly under water supply pressure. As hot water is drawn from the appliance, cold water is immediately added.
The air required for combustion is forcibly delivered to the burner q by the fan r. The gas is fed to the burner q via the gas control p. Thanks to the modulated supply of gas and air, the optimum gas/air mixture is always achieved. The special construction of the burner causes the mixture to form a vortex (the cyclone effect), before it becomes ignited. Because of this vorticity, ignition at the glow igniter t is improved, and the combustion efficiency is also optimised. Through the special design of the heat exchanger k, the flue gases are first led downwards via the combustion chamber, then upwards again via the heat exchanger, then once more downwards beside the water in the tank. In this process, the flue gases gradually become cooler. Because the cooled flue gases flow alongside the cold water below in the tank, they start to condense. This condensation causes latent heat energy to be released, which is transferred to the cooler water, and thereby increases the performance of the unit. The water of condensation yielded by this process is discharged via the siphon w.
The PU insulation layer x prevents heat loss. The inside of the tank is enamelled to protect against corrosion. The magnesium anodes i provide extra protection against corrosion.
For use during maintenance, the appliance has a inspection and cleaning opening l.

2.3 The appliance’s heating cycle

2.4 Protection for the appliance

The entire appliance is controlled (and monitored) by theThermoControl d. The temperature sensor T1 g (in the top of the tank j) and the temperature sensor T2 m (in the bottom of the tank) measure the water temperature. These temperatures are sent to the ThermoControl. Based on these two observations, the ThermoControl calculates a net water temperature: T lies between the temperatures measured at the top and bottom of the tank. As soon as T registers a ‘heat demand’. The gas control p is opened, and the gas is mixed with air. This mixture is ignited by the glow igniter t and the water becomes heated. As soon as T ThermoControl stops the heating cycle.
Both when registering and ending the heat demand, the ThermoControl assumes a certain margin. We refer to this margin as the hysteresis (see paragraph ’9.2 Setting the hysteresis’).
The ThermoControl monitors the water temperature and ensures safe combustion. This is achieved by:
the Water temperature protection;
the Gas control;
the Fan;
the Pressure switch;
the Ionisation rod.
falls below the set water temperature (T
net
rises above T
net
, the heat demand ends, and the
set
. The value of T
net
), the ThermoControl
set
net
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2.4.1 Water temperature protection

With temperature sensor T1 g and temperature sensor T2 m, the ThermoControl monitors three temperatures which are important for safety.
Ta bl e 2 .1 explains the functioning of the temperature sensors.
Tab le 2. 1 Temperature protection
Protection Description
Protection for the appliance
Against frost
< 5°C or T2 < 5°C)
(T
1
For maximum water temperature (T
> 85°C or T2 > 85°C)
1
For extra safety (T
> 93°C or T2 > 93°C)
1

2.4.2 Gas control

2.4.3 Fan

The frost protection cuts in. The water is heated to 20°C.
The high-limit safeguard serves to prevent overheating and/or excessive formation of scale in the appliance. Should the high-limit safeguard be activated, the heating is halted. This causes the water in the tank to cool down. Once the water has cooled sufficiently (T1 < 78 °C), the ThermoControl resets the appliance.
A lockout error of the water heater controller takes place. The controller must be manually reset before the appliance can resume operation (see paragraph
’6.3 Error conditions’). The reset may only be performed once T
The ThermoControl opens the gas control so that gas can be supplied to the burner. As a safety measure, the gas control has two valves. Both valves shut off the gas supply.
Smooth ignition is achieved by opening the gas control with a delay (‘softlite’).
The fan provides an optimum air supply when there is a heat demand. A safety aspect is that the fan ensures that any gases present in the combustion chamber get removed, both before and after combustion. We refer to this as pre- and post-purge.
The fan speed is continuously monitored by the ThermoControl. The ThermoControl takes control if the speed of rotation varies too much from the value set.
< 78°C.
1

2.4.4 Pressure switch

The pressure switch ensures the discharge of flue gases and the supply of incoming air during the pre-purge and normal running of the appliance. The standard position of the pressure switch is open. When sufficient pressure differential is reached, the pressure switch closes. However, in the event of a fault, the pressure switch will be tripped open, and the heating cycle will be interrupted.
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Table 2.2 shows the trip point per appliance.
Tabl e 2 .2 Pressure switch trip points
AppliancePressure differential [Pa]
Closing Opening

2.4.5 Ionisation rod

2.5 Safety of the instal­lation

2.5.1 Unvented installation

BFC 28 >
BFC 30 >
BFC 50 >
BFC 60 >
635 < 605
855 < 825
885 < 855
1085 < 1055
n Remark
The trip point of the pressure switch is not adjustable.
To ensure that no gas will flow when there is no combustion, an ionisation rod has been fitted. The ThermoControl uses this rod for flame detection, by means of ionisation detection. The ThermoControl cuts in, the instant it detects that there is a gas flow but no flame.
In addition to the appliance’s standard safety monitoring, the appliance must also be protected by an expansion vessel, pressure overflow valve, non-return valve and a T&P valve.
Use of an expansion vessel, a pressure relief valve and/or a pressure reducing valve depends on the type of installation: unvented or vented.
With an unvented installation, a pressure relief valve and expansion vessel prevent excessive pressure in the tank. This prevents damage being caused to the enamelled coating (in the appliance) or to the tank. A non-return valve prevents excessive pressure in the water supply system. This valve also prevents water from flowing backwards from the tank into the cold water supply system. The pressure reducing valve protects the installation against an excessively high water supply pressure (> 8 bar). These components are fitted to the cold water pipe. See paragraph ’3.6.1 Cold water side’.

2.5.2 Vented installation

With a vented installation, excess pressure is taken up by the open water reservoir. The level of the water reservoir determines the maximum working pressure in the tank, which may not exceed 8 bar. The installation must also be fitted with an overflow from the hot water pipe, which discharges into the water reservoir. See paragraph ’3.6.2 Hot water side’.

2.5.3 T&P valve

A T&P valve is only mandatory in an ‘unvented’ installation. However, A.O. Smith also recommends the use of a T&P valve in ‘vented’ installations.
A T&P valve monitors the pressure in the tank, and the water temperature at the top of the tank. If the pressure in the tank becomes excessive (>10 bar) or the water temperature is too high (>97°C), the valve will open. The hot water will immediately flow out of the tank. Because the appliance is under water supply pressure, cold water will automatically flow into the tank. The valve remains open until the unsafe situation has been averted. A connecting point for a T&P valve is standard on the appliance. See paragraph ’3.6.2 Hot water side’.
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3 Installation

Warning
The installation should be carried out by an approved installer in compliance with the general and local regulations imposed by the gas, water and power supply companies and the fire service.
The appliance may only be installed in a room which complies with the requirements stated in national and local ventilation regulations.
Refer also to paragraph ’1.3 Regulations’.
3.1 Introduction This chapter describes the installation activities to be carried out before the
appliance may be started up, namely:

Packaging;

Environmental conditions;

Technical specifications;
Water connections, Unvented;
Water connections, Vented;
Gas connection;
Air supply and flue gas discharge;
Electrical connection;
Checking the supply pressure and burner pressure;
Conversion to a different gas category.
n Remark
Starting up the appliance is described in chapter ’7 Starting up and shutting
down’.
3.2 Packaging To avoid damaging the appliance, remove the packaging carefully. We
recommend unpacking the appliance at or near its intended location.
cNote
The appliance may only be manoeuvred in an upright position. Take care that the appliance is not damaged after unpacking.
3.3 Environmental
conditions
The BFC appliance is a room-sealed appliance. Installation types possible with this appliance are C13, C33, C43, C53 and C63. This makes it possible to install the appliance in either a closed or an open boiler room.
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3.3.1 Humidity and ambient temperature

The boiler room must be frost-free, or be protected against frost. Table 3.1 shows the environmental conditions that must be adhered to, for correct functioning of the electronics present in the appliance to be guaranteed.
Table 3 . 1 Humidity and ambient temperature specifications
Humidity and ambient temperature
Humidity max. 93% RH at +25°C
Ambient temperature Functional: 0 ≤ t ≤ 60°C

3.3.2 Maximum floor loading

In connection with the appliance’s weight, take account of the maximum floor loading, see Tab le 3 .2 .
Table 3 . 2 Weight specifications related to maximum floor loading
Weight of the appliance filled with water
BFC 28 392 kg
BFC 30, BFC 50, BFC 60 593 kg

3.3.3 Water composition

The appliance is intended for heating drinking water. The drinking water must comply with the regulations governing drinking water for human consumption.
Table 3.3 shows these requirements.
Table 3 . 3 Water specifications
Water composition
Hardness (alkaline earth ions)
Conductivity > 125 µS/cm
Acidity (pH value) 7.0 < pH value < 9.5
n Remark
If the water specifications deviate from those stated in Ta bl e 3 .3 , then the tank protection cannot be guaranteed. See also chapter ’13 Warranty (Certificate)’.

3.3.4 Working clearances

For access to the appliance it is recommended that the following clearances are observed (see Figure 3.2):
AA: around the appliance’s control column and cleaning openings: 100 cm.
BB: around the appliance itself: 50 cm.
Above the appliance (room to replace the anodes):
- 100 cm if using fixed anodes, or
- 50 cm if using flexible anodes.
> 1.00 mmol/l:
German hardness >5.6° dH
French hardness > 10.0° fH
British hardness > 7.0° eH
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a
Environmental conditions
If the available clearance is less than 100 cm, flexible magnesium anodes may be ordered from A.O. Smith, the installer / supplier.
n Remark
When installing the appliance, be aware that any leakage from the tank and/ or connections can cause damage to the immediate environment or floors below the level of the boiler room. If this is the case, then the appliance should be installed above a wastewater drain or in a suitable metal leak tray. The leak tray must have an appropriate wastewater drain and must be at least 5cm deep with a length and width at least 5cm greater than the diameter of the appliance.
Figure 3.1 Working clearances
IMD-0073
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3.4 Technical specifications

The appliance is supplied without accessories. Check the dimensions and other specifications for the accessories to be used, based on Figure 3.2 and
Table 3.6.
IMD-0073
Figure 3.2 Plan and elevation of the appliance
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Tab l e 3.4 Dimensions
Technical specifications
Dime nsion
A Total height (mm) 1370 1900 1900 1900
D Diameter of the appliance (mm) 705 705 705 705
G Diameter of air supply/flue gas discharge (mm) 80/125 100/150 100/150 100/150
K Height of the gas connection (mm) 1270 1810 1810 1810
M Height of cold water supply connection (mm) 160 160 160 160
N Height of hot water outlet connection (mm) 1405 1920 1920 1920
P Height of cleaning and inspection opening (mm) 200 200 200 200
R Height of drain valve (mm) 75 75 75 75
S Height of T&P valve (mm) 890 1415 1415 1415
W Height of condensation drainage (mm) 110 110 110 110
X Height of air supply connection (mm) 1205 1730 1730 1730
1 Cold water supply connection R 1½ (external)
2 Hot water outlet connection R 1½ (external)
3 Gas control connection Rp ¾ (internal)
4 Drain valve connection (external) ¾”
Description BFC 28 BFC 30 BFC 50 BFC 60
5 T&P valve connection (internal) ¾” NPT 1 - 11.5 NPT
6 Dimensions cleaning and inspection opening
7 Condensation drainage connection (internal) Ø 40 mm Rp 1 Rp 1 Rp 1
Tab le 3. 5 General and electrical data
DESCRIPTION Unit BFC 28 BFC 30 BFC 50 BFC 60
Capacity litres 217 368 368 368
Maximum working pressure bar 8 8 8 8
Empty weight kg 175 225 225 225
Heating time T = 45
Number of anodes - 4 4 4 4
Number of bar burners/orifices - n.a. n.a. n.a. n.a.
Number of flue tubes/flue baffles - 1/? 1/? 1/? 1/?
Fan rotational speed at ignition r. p.m. 4500 4500 4500 4500
Working speed of fan rpm 4980 5400 6000 6660
Diameter of air restrictor mm 23.0 23.0 28.0 29.0
(mm)
o
C minutes 23 35 24 20
95 x 70
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Tabl e 3 .5 General and electrical data
DESCRIPTION Unit BFC 28 BFC 30 BFC 50 BFC 60
Electrical power consumption W 175
Supply voltage VAC 230 (-15% +10%)
Mains frequency Hz 50 (±1 Hz)
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Tab l e 3.6 Gas data

Installation diagram
Gas category dataII
Data for natural gas 2H: G20-20 mbar
Orifice diameter mm 4.90 5.10 7.00 7.10
Nominal load (upper value) kW 32.1 34.5 52.6 63.2
Nominal capacity kW 30.3 32.8 48.6 59.6
Supply pressure mbar 20 20 20 20
Burner pressure mbar 8.5 8.5 8.5 11.5
Gas consumption
Data for LP gas 3+
General
Orifice diameter mm 2.50 2.60 3.40 3.80
Restrictor diameter mm n.a. n.a. n.a. n.a.
G30-30 mbar (butane)
Nominal load (upper value) kW 30.7 32.8 50.6 59.4
Supply pressure mbar 37 37 37 37
Burner pressure
Gas consumption
(1)
(2)
(1)
Unit BFC 28 BFC 30 BFC 50 BFC 60
2H3+
m3/h 3.1 3.3 5.0 6.0
mbar 37 37 37 37
kg/h 2.2 2.4 3.7 4.3
G31-37 mbar (butane)
Nominal load (upper value) kW 29.0 30.9 50.3 59.1
Supply pressure mbar 37 37 37 37
Burner pressure
Gas consumption
(1) Based on 1013.25 mbar and 15oC. (2) If using a flat sealing plate instead of a burner pressure regulator, it is assumed that the burner pressure is equal to the supply pressure.
In practice however, the burner pressure will be lower.

3.5 Installation diagram

(2)
(1)
Figure 3.3 shows the water and gas connection diagrams for unvented and
vented installations. The following paragraphs, describing the connections in detail, make reference to these diagrams
mbar 37 37 37 37
kg/h 2.1 2.2 3.6 4.2
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Legend
a pressure-reducing valve
(mandatory)
b expansion vessel (mandatory)
c T&P valve (mandatory)
d stop valve (recommended)
e non-return valve (mandatory)
f circulation pump (optional)
g drain valve
h gas valve (mandatory)
i stop valve (mandatory)
j temperature gauge (optional)
k condensation drainage
(mandatory)
l hot water draw-off points
m pressure relief valve
(mandatory)
n water cistern
o float valve
p 3-way venting valve
(recommended)
q overflow pipe
a cold water supply
b hot water outlet
c circulation pipe
d gas supply
e flue gas discharge and air
supply
UNVENTED
d
h
VENTED
d
b
l
i
j
T
e
E N
T
T
E
E
S
R
E R
c
d
f e
d
c
b
a
a
m
ei
k
g
po
IMD-0139
a
q
l
b
i
T
j
e
c
n
h
i
c
a
c
d
efd
k
g
IMD-0138
Figure 3.3 Installation diagrams
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3.6 Water connections,
Unvented

3.6.1 Cold water side

3.6.2 Hot water side

Water connections, Unvented

See a in Figure 3.3.
1. Fit an approved stop valve i on the cold water side as required by regulations. Refer also to paragraph ’1.3 Regulations’.
2. The maximum working pressure of the appliance is 8 bar. Because the pressure in the water pipe at times can exceed 8 bar, you must fit an approved pressure-reducing valve a.
3. Fit a non-return valve e and an expansion vessel b.
4. Fit a pressure relief valve m and connect the overflow side to an open wastewater pipe.
See b in Figure 3.3.
n Remark
Insulating long hot water pipes prevents unnecessary energy loss.
1. Optional: fit a temperature gauge j to be able to check the temperature of the tap water.
2. Fit the T&P valve c.
3. Fit a stop valve i in the hot water outlet pipe, for use when servicing.

3.6.3 Circulation pipe

See c in Figure 3.3.
If an immediate flow of hot water is required at draw-off points, a circulation pump can be installed. This improves comfort and reduces water wastage.
1. Fit a circulation pump f of the correct capacity for the length and resistance of the circulation system.
2. Fit a non-return valvee behind the circulation pump to guarantee the direction of circulation.
3. Fit two stop valves d for service purposes.
4. Connect the circulation pipe to the cold water supply pipe.

3.6.4 Condensation drainage

1. Fit a sloping wastewater pipe to the siphon k for condensation drainage and connect this to the wastewater discharge in the boiler room.
cNote
All piping behind the siphon must be condensation-resistant.
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3.7 Water connections, Vented

3.7.1 Cold water side

3.7.2 Hot water side

Installation
is
See a in Figure 3.3.
1. Fit an approved stop valve i on the cold water side between the water cistern n and the appliance, as required by regulations. Refer also to paragraph ’1.3 Regulations’.
See b in Figure 3.3.
n Remark
Insulating long hot water pipes prevents unnecessary energy loss.
1. Fit the T&P valve c.
2. Optional: fit a temperature gauge j to be able to check the temperature of the tap water.
3. Fit a stop valve i in the hot water outlet pipe, for use when servicing.
4. If a circulation pipe is to be fitted, then refer to paragraph 3.7.3.

3.8 Gas connection

3.7.3 Circulation pipe

See c in Figure 3.3.
If an immediate flow of hot water is required at draw-off points, a circulation pump can be installed. This improves comfort and reduces water wastage.
1. Fit a circulation pump f of the correct capacity for the length and resistance of the circulation system.
2. Fit a non-return valvee behind the circulation pump to guarantee the direction of circulation.
3. Fit two stop valves d for service purposes.
4. Connect the circulation pipe to the cold water supply pipe.

3.7.4 Condensation drainage

See paragraph ’3.6.4 Condensation drainage’.
Warning
Gas installation may only be carried out by an authorised installer in compliance with the general regulations imposed by the gas company. Refer also to paragraph ’1.3 Regulations’.
cNote
Make sure that the diameter and length of the gas supply pipe are large enough to supply sufficient capacity to the appliance.
See d in Figure 3.3.
1. Fit a gas valve h in the gas supply pipe.
2. Blow the gas pipe through before use, to be sure it is clean.
3. Close the gas valve.
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3.9 Air supply and flue gas discharge

Air supply and flue gas discharge
4. Fit the gas supply pipe to the gas control.
Warning
Check for leaks after fitting.
Warning
The installation should be carried out by an authorised installer, in compliance with the general and local regulations imposed by gas, water supply and power supply companies and the fire service. Refer also to paragraph ’1.3 Regulations’.
Depending on the approved installation types, there are several alternatives for connecting the air supply and flue gas discharge. The BFC appliances are approved for installation types C13, C33, C43, C53 and C63.
The most common installation types are:
C13: Concentric wall flue terminal and
C33: Concentric roof flue terminal.
This manual describes these installation types. If an explanation of other types of installation is required, please contact A.O. Smith.
cNote
A.O. Smith prescribes the use of a roof or wall-mounted terminal, exclusively of a type approved for the appliance. See paragraph
’3.9.1 Concentric wall flue terminal’ and ’3.9.2 Concentric roof flue terminal’.
Use of an incorrect roof or wall-mounted terminal can cause the installation to malfunction.
n Remark
Make sure that the chimney discharges into an area where this is permitted for this category of appliance.
Ta bl e 3 .7 shows the maximum length of the chimney configurations. The
following requirements must also be fulfilled:
the maximum chimney length is 15 metres.
The maximum permitted number of 45° or 90° bends is four.
Tabl e 3.7 Chimney configurations for concentric wall and roof termination.
Dimension
(1)
A 0-15 m 0-15 m 0-15 m 0-15 m
B 0-15 m 0-15 m 0-15 m 0-15 m
BFC 28 BFC 30 BFC 50 BFC 60
a + B max. 15 m max. 15 m max. 15 m max. 15 m
1. See ’Figure 3.4 Wall flue terminal’ and ’Figure 3.5 Roof flue terminal’.
cNote
If you make use of horizontal piping, then this must slope towards the appliance with a minimum of 5 mm per metre running length!
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3.9.1 Concentric wall flue terminal

Table 3.8 shows the wall flue terminal prescribed by A.O. Smith (installation
type C13).
B
A
IMD-0075
Figure 3.4 Wall flue terminal
Table 3 . 8 Concentric wall flue terminal specifications
Specification Description
Manufacturer Muelink & Grol
Model M2000 MDV SE
Pipe material, flue gas discharge Thick-walled aluminium with lip ring seal
Pipe material, air intake Thin-walled galvanised sheet steel
Pipe diameter Concentric
BFC 28: Ø 80/125 mm.
BFC 30, 50 and 60: Ø 100/150 mm.
1. The M2000 MDV SE model is a special version of the Mugro 3000 series. No other wall flue terminal may be used, as the BFC-appliance is approved exclusively for this model of wall flue terminal. You can order the wall flue terminal from A.O. Smith or your trade supplier, by specifying model: M2000 MDV SE.
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3.9.2 Concentric roof flue terminal

A.O. Smith Water Products Company prescribes the roof flue terminal (installation type C33) as specified in Ta b le 3 .9 .
Tabl e 3.9 Concentric roof flue terminal specifications
Specification Description
Manufacturer Muelink & Grol
Model M2000 DDV SEC HR
Air supply and flue gas discharge
(1)
Pipe material, flue gas discharge
Pipe material, air intake Thin-walled galvanised sheet steel
Pipe diameter Concentric
1. The model M2000 DDV SEC HR is a special version of the Mugro 3000 series. No other roof flue terminal may be used, as the BFC- appliance is approved exclusively for this model of roof flue terminal. You can order the roof flue terminal from A.O. Smith or your trade supplier, by specifying model: M2000 DDV SEC HR.
Thick-walled lip ring seal
BFC 28: 80/125 mm.
BFC 30, 50 and 60: Ø 100/150 mm.
IMD-0004
Figure 3.5 Roof flue terminal
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