AO Smith Water Heater 28 30 50 60 User Guide

Release R.1.3 UK  
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60  
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EF  
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Installation  
User and  
Service Manual  
WATER PRODUCTS  
COMPANY  
A DIVISION OF A. O. SMITH CORPORATION  
XTRA HIGH EFFICIENCY  
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your installer  
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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  
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.  
Trademarks  
Liability  
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  
+31 40 294 25 00  
+31 40 294 25 37  
+31 40 294 25 38  
+31 40 294 25 39  
General:  
Sales:  
Help desk:  
Fax:  
E-mail:  
Internet:  
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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Instruction Manual BFC  
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gis  
Table of contents  
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Instruction Manual BFC  
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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  
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.  
0063  
1.2 What to do if you  
smell gas  
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.  
1.3 Regulations  
As the (end) user, installer or service and maintenance engineer, you must  
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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1
Introduction  
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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.  
Table 1.1 Target group symbols  
Symbol  
g
i
s
Target group  
(End) user  
installer  
Service and maintenance engineer  
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  
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1.7 Overview of this  
document  
Table 1.2 provides an overview of the contents of this document.  
Table 1.2 Contents of document  
Chapter  
Target groups  
Description  
This chapter describes how the appliance functions.  
This chapter describes the installation activity to be completed  
before you actually start up the appliance.  
This chapter describes how to fill and drain the appliance.  
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.  
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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1
Introduction  
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Introduction  
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2 Functioning of the  
appliance  
2.1 Introduction  
Topics covered in this chapter:  
2.2 Functional  
Figure 2.1 shows a cut-away view of the appliance.  
description of the  
appliance  
Legend  
a
b
p
q
a plastic top cover  
b hot water outlet  
c electrical connection block  
d ThermoControl  
c
r
s
d
e
f
e pressure switch  
f control panel  
g temperature sensor T  
h combustion chamber  
i anode  
1
g
t
u
j tank  
k heat exchanger  
h
i
j
k
l inspection and cleaning  
v
opening  
m temperature sensor T  
n cold water inlet  
o drain valve  
p gas control  
q burner  
2
r fan  
s air supply hose  
t glow igniter  
u ionisation rod  
v chimney pipe  
w siphon  
l
m
w
x
n
o
x PU insulation layer  
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  
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 . The value of T  
net  
net  
lies between the temperatures measured at the top and bottom of the tank. As  
soon as T falls below the set water temperature (T ), the ThermoControl  
net  
set  
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 rises above T , the heat demand ends, and the  
net  
set  
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  
2.4 Protection for the  
appliance  
The ThermoControl monitors the water temperature and ensures safe  
combustion. This is achieved by:  
the Gas control;  
the Fan;  
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Protection for the appliance  
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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.  
Table 2.1 explains the functioning of the temperature sensors.  
Table 2.1 Temperature protection  
Protection  
Description  
Against frost  
The frost protection cuts in. The water is heated to 20°C.  
(T < 5°C or T < 5°C)  
1
2
For maximum water temperature The high-limit safeguard serves to prevent overheating and/or excessive  
(T > 85°C or T > 85°C)  
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.  
1
2
Once the water has cooled sufficiently (T < 78 °C), the ThermoControl resets  
1
the appliance.  
For extra safety  
A lockout error of the water heater controller takes place. The controller must  
be manually reset before the appliance can resume operation (see paragraph  
(T > 93°C or T > 93°C)  
1
2
’6.3 Error conditions’). The reset may only be performed once T < 78°C.  
1
2.4.2 Gas control  
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’).  
2.4.3 Fan  
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.  
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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