A.O. Smith BTI - 65 Guide

MODEL BTI 65 G
HOT WATER STORAGE HEATER
UNITED KINGDOM / IRELAND
INSTALLATION AND USER
INSTRUCTION

2
Read these installation instructions rst before installing the appliance. Carefully read the
user instructions before igniting the appliance. Failure to follow these instructions may
lead to risk of explosion and/or re and could cause material damage and/or bodily harm.
Installation and commisioning should be carried out by a qualied competent installer.
The type of gas and the value at which the appliance is set standard in the factory are
registered on the rating plate. The appliance may only be installed in a room if this room
meets the ventilation requirements.
A.O. SMITH ACCEPTS NO RESPONSIBILITY FOR WARRANTY, SERVICE AND/
OR PRODUCT LIABILITY IN CASE OF UNAUTHORISED ALTERATIONS, PRODUCT
MODIFICATIONS OR REPAIR.

3
CONTENTS PAGE
1. GENERAL
1.1 Description .......................................................................................................... 4
1.2 Technical safety equipment ................................................................................ 6
1.2.1 Gas control valve ................................................................................................ 6
1.2.2 Control panel ...................................................................................................... 6
1.2.3 Operation of the storage water heater ................................................................ 7
1.2.4 Combustion products discharge safety device ................................................... 7
1.3 Technical information .......................................................................................... 8
1.3.1 Dimensions ......................................................................................................... 8
1.3.2 Technical data ................................................................................................... 10
2. FOR THE INSTALLER
2.1 Installation instructions ..................................................................................... 12
2.1.1 Installation ........................................................................................................ 12
2.1.2 Water circulation system................................................................................... 13
2.1.3 Gas connection ................................................................................................. 15
2.1.4 Flue system ...................................................................................................... 15
2.1.5 Flue down draught safety device ...................................................................... 15
2.1.6 Electrical connection ......................................................................................... 15
2.2 Commissioning ................................................................................................. 16
2.2.1 Filling the water heater ..................................................................................... 16
2.2.2 Putting in to operation ....................................................................................... 16
2.2.3 Shut down ......................................................................................................... 16
2.3 Removing and replacing the control panel front cover ..................................... 17
2.4 Setting the gas pressure ................................................................................... 17
2.5 Temperature regulation ..................................................................................... 18
2.6 Converting to another type of gas .................................................................... 18
2.7 Maintenance ..................................................................................................... 19
2.7.1 Magenesium anode .......................................................................................... 19
2.7.2 Cleaning ........................................................................................................... 19
2.7.3 Decalcication .................................................................................................. 19
2.7.4 Spare parts ....................................................................................................... 19
2.8 Inlet combination .............................................................................................. 20
2.9 Gas smell .......................................................................................................... 20
2.10 Condensation ................................................................................................... 20
3. FOR THE USER
3.1 Commisioning ................................................................................................... 21
3.1.1 Filling the water heater ..................................................................................... 21
3.1.2 Putting into operation ........................................................................................ 21
3.1.3 Use ................................................................................................................... 21
3.2 Fault overview .................................................................................................. 22
4. WARRANTY. .......................................................................................................23
5. Appendix 1. ........................................................................................................ 25

4
1. GENERAL
1.1 Description of the
appliance
Construction of the water heater is in
accordance with the European standard
for gas heated water storage heaters for
sanitary application (EN89). The appliance
thus meets the European Directory for
Gas Appliances and is therefore entitled to
carry the CE-marking. It is an open ued
appliance without ventilator and with a ue
gas down draught safeguard, a Thermal
Reux Safeguard (TRS) (category
B11BS). The water heater is suitable for a
maximum working pressure of 8 bar. The
water heater tank is manufactured from
low carbon sheet steel and is glasslined on
the inside. In addition the tank is tted with
a magenesium anode as extra protection
against corrosion. A thick, CFC-free, PU
insulation layer covered in a steel jacket
reduces unnecessary heat loss. When the
appliance is lled with water it continuously
is under water pressure. As hot water is
drained from the tank, cold water is added
immediately. A ue bafe has been placed
in the ue tube to improve heat tranfer. The
ue gasses pass their heat on to the water
by means of radiation and convection. The
exhaust of the ue gasses is realized by
natural thermal draught (see gur 1).
Dead legs on a hot water installation are
undesireable. Where possible they should
be avoided. When the inclusion on the
system of a dead leg is unavoidable the
following restrictions should be applied:
- for pipes not eceeding 19 mm. inside
diameter; maximum length of dead leg
permitted 12 metres;
- for pipes exceeding19 mm. but not
exceeding 25 mm. inside diameter;
maximum lenght of dead leg 7,5 metres;
- for pipes with an inside diameter
exceeding 25 mm. maximum length of
dead leg 3 metres.

5
1) Draught diverter
2) Hot water outlet
3) Insulation
4) Flue tube
5) Glass lined tank
6) Gas valve and spark ignition
7) Control panel
8) Inspection cover plate
9) Intermittent pilot burner
and ame probe
Figur 1 - Cross section of the heater
10) Cold water inlet
11) Combustion products discharge
safety device
12) T&P valve connection
13) Outer casting
14) Flue bafe
15) Magnesium anode
16) Drain valve and secondary
return connection
17) Main burner
11
14
15
16
17
1
2
3
4
5
6
9
7
13
10
12
8
AOS 1120

6
1129
1.2 Technical safety
equipment
1.2.1 Gas control valve
The water heater is equipped with a gas
control wich regulates the ow of gas to
the burner. The gas block is equipped
with a safety valve, gas valve and burner
control (on a standard natural gas
setting). To ensure improved ignition the
gas control valve opening mechanism is
tted with a delay (softlite).
The gas control block is suitable for
gasses from the rst, second and third
gas family. The maximum inlet pressure
is 60 mbar.
The automatic incandescent ignition (hot
surface) ensures that the burner ignites
as soon as there is a demand for heat.
1.2.2 Control panel
Temperature control for the water heater
is housed in the control panel (See gur
2). For safety purposes, heaters are
always tted with two thermostats: a
control thermostat is adjustable between
40 °C and 80 °C and a safety thermostat
90 °C. The control panel is tted with
an ON/OFF switch (I/0). At setting
”I”, the gas control is activated on the
basis of heat demand from the control
thermostat. At setting ”0” the heater is
switched off.
A) Hot water outlet
B) Cold water inlet
1) Electrical connection
2) ON/OFF switch
3) Ignition controller reset button
4) Control thermostat knob
5) Safety thermostat reset button
Figur 2 - Top view of the heater

7
1.2.3 Operationofthestorage
water heater.
Normal operation
When there is a demand for heat
a waiting period of about 1 second
elapses before the built-in spark
generator and pilot gas valve are
switched on. The ignition sparks ignite
the pilot burner and the resulting ame
is detected by the ionisation electrode.
Almost immediately after the pilot
ame is detected, sparking stops and
the main gas valve is openend. The
main burner is lit by the pilot ame.
The unit is now in operation. When the
temperature of the water in the unit
reaches the temperature that is set with
the thermostat, the thermostat switches
and disconnects the electrical heat
demand signal to the burner controller.
The gas valves are then closed.
Ignition failure
If the ame is not established within
the safety period the automatic ignition
controller locks out. The safety period is
about 25 seconds. Lock-out is indicated
by the lamp in the RESET-button on
the control panel. The unit has to be
manually reset by pushing the reset
button. If the ame is lost during normal
run, the automatic ignition controller
repeats the start sequence.
1.2.4 Combustion products
discharge safety device
The heater has been tted with a
combustion products discharge safety
device. It is the function of the safety
device to prevent ue gases from the
water heater entering the room where
the water heater has been placed,
instead of passing through the ue to
outside atmosphere. The gas supply
is disconnected as soon as the device
is activated by hot gases owing over
the sensor. After the cause of the re-
entry of ue gases has been traced the
device can be put back into operation
by pressing its reset button. If this
failure occurs frequently, this indicates
that the ue suffers from down draught
conditions. It is recommended that a
competent person carry out the necessary
remedial action.
Important
The combustion products discharge
safety device should never be put out
of operation. Re-entry of ue gases
to the building could be harmful and
cause poisoning or death.

8
1.3 Technical information
1.3.1 Dimensions
These water heaters are only suitable for
a ue tube with minimal the announced
diameter (dimension G).
All dimensions are given in mm. (rounded off on 5mm). See gur 3.
Dimensions BTI65
A 1680
B1510
D520
E655
G100
K 340
M1540
N1540
R 295
S1350
1Cold water inlet
2Hot water outlet
3Gas control
4Drain valve
5T&P relief valve tapping
6Clean out

9
Figur 3 - Dimensions

10
1.3.2 Technical data device category: II2H3+
* Gas consumption at 1013,25 mbar and 15 °C
** For a leak proof sealed connection European coupling pieces can be used on the NPT
connection nipples with a pipe thread of ISO 228/1
Description unit BTI 65
DATA NATUREL GAS G20 - 20 mbar
Nominal capacity kW 12.7
Nominal load (gross) kW 18.1
Supply pressure mbar 20
Burner pressure mbar 12.0
Gas consumption * m3/h 1.7
Diameter main orice mm 3.40
Diameter pilot orice mm 0.56/0.41
Heating time ∆T= 45K min 45
DATA BUTANE G30 - 28/30 mbar
Nominal load (gross) kW 17.2
Nominal capacity kW 12.3
Supply pressure mbar 30
Gas consumption * kg/h 1.3
Diameter main orice mm 1.90
Diameter pilot orice mm 0.23
DATA PROPANE G31 - 37 mbar
Nominal heat input (gross) kW 16.4
Output kW 11.7
Inlet pressure mbar 37
Gas consumption * kg/h 1.2
Diameter main orice mm 1.90
Diameter pilot orice mm 0.23
GENERAL
Storage capacity liters 178
Water connections** - 3/4"-14NPT
Gas connection - Rp1/2
Drain valve - 3/4"-14NPT
Anode -3/4"-14NPT
T&P plug - 3/4"-14NPT
Maximum operating pressure bar 8
Empty weight kg 93

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Electrical connection
Electrical Frequency Electrically
supply fused to
220/240 V AC 50 Hz 5A
Ionisation current.
The minimal ionisation current is 0.9
micro-Amperes DC. Below this current
the burner controller will assume
no ame present. When in normal
operation, the ionisation current wil be
about 1.2 to 1.3 micro-Amperes DC
when only the pilot ame is burning.
(Adjust the main burner pressure to
zero to be able to measure under this
condition) With pilot- and main burner in
operation, the ionisation current will be
about 6.0 and 6.3 micro-Amperes DC.
Ionisation current can be measured by
connecting a universal-meter in series
in the connection to the ionisation
electrode. Make sure to measure in
Direct Current; Alternating Current in fact
gives no information about the system’s
behaviour.

12
2. FOR THE INSTALLER
2.1 Installation instructions
This water heater must be tted in a
location which will permit the provision
os an approved ue system and
adequate ventilation.
A service clearance of 15 cm at the sides
and rear of the unit and 60 cm at the front
of the unit should be allowed for ease of
servicing. Adequate distance must be
allowed between the top of the unit and
any obstruction or ceiling to allow the ue
bafe and anode to be inspected, cleaned
or in the case of the anode replaced if
necessary.
The water heater must stand on a level
surface resistant to heat, insulted in
accordance with local bylaws and Building
Regulations 1985, with sufcient strength
to support the weight of the unit when full
of water.
This water heater must not be installed
in a bathroom, bedroom or in a cupboard
opening on to such rooms. This water
heater must not be installed in any area
where amable materials are used or
stored.
Insufcient ventilation may give rise to
a risk of re, explosion or suffocation. If
in doubt consult the national and local
regulations governing the installation of
gas appliances or your British gas sevice
department.
2.1.1 Installation
The installation of this water heater should
be carried out by a suitably qualied
competent person. It is a criminal offence
for unqualied persons to install gas
equipment.
Installation should be carried out in
accordance with all local authority and
Building Regualions, Model Water Bylaws,
bylaws of the local water supplier, Building
Standards (Scotland) (Consolidation)
Regulations and any relevant requirements
of the Local Authority, local gas regions
and the following British Standards (current
editions):
For domestic applications:
BS 5440 - part 1 and part 2.
BS 5546 - Installation of gas hot
water supplies for domestic
purposes.
BS 6700 - Specications for design,
installation and maintenance
of services supplying water
for domestic use within
buildings and their curtilages.
BS 6798 - Specication for installation
of gas red hot water boilers
of rated input not exceeding
60 kW.
BS 6891 - Specication for installation
of low pressure gas pipework
of up to 28 mm in domestic
premises.
For non-domestic applications:
BS 5400 - part 1 and part 2.
BS 6798 - Specication for installation
of low pressure gas pipework
of up to 28 mm in domestic
premises.
CP 342 - Code of practice for
centralised hot water supply
part 2, buildings other than
individual dwellings and the
following additional Codes of
Practice.
IM/2 - Purging procedures for non-
domestic gas installations.
IM/5 - Soundness testing
procedures for industrial and
commercial gas installations.
IM/11 - Flues for commercial and
industrial gas red boilers
and air heaters.
IM/16 - Notes on installation of
pipework (excluding 25 mm
and below).
Some chemicals produce vapours which
can cause rapid failure of main- and
pilotburners and storage tanks if they are
drawn into the combustion air supply.

13
Figur 4 - Connection diagram vented
systems
Therefore if this water heater will be
used to supply hot water to:
- hairdressers,
- dry cleaners,
- industrial degreasing processes
or any other area where
compounds containing halogens are
used and stored, care should be ta
ken that all primary and secondary
air is drawn from outside
atmosphere free of such
contaminents.
For futher advise contact A.O. Smith.
2.1.2 Water circulation system
A.O. SMITH water heaters are suitable
for connection to vented, unvented and
pumped pressurised systems. In each
case appropriate valves and ttings
should be used to ensure the system
complies with the requirements of the
water by laws, and appropriate building
regulations.
When tting it is essential the rules of
‘good practice’ are applied at all stages
of installation.
Vented systems (See gur 4)
If the water heater is to be connected to
a cold feed tank or cistern the hot water
supply pipe must include an open vent
which discharges over the cold feed
cistern. The cold feed cistern must have
an actual capacity of greater volume
than the hourly recovery rate of the water
heater(s) which it supplies. The minimum
actual capacity is 50 gallons or 227 litres.
1) Manual gas valve
2) Stop valve
3) Three way valve
4) Safety valve
5) Non return valve
6) Circulation pump
7) Drain valve
A) Gas supply
B) Hot water outlet
C) Cold water inlet
D) Overow
E) Return circulation loop
1105
AOS 1105

14
1119
Unvented system (See gur 5)
To install an A.O. Smith water heater on
an unvented cold water supply system
a kit of valves and ttings sted by the
water reseach centre and complying
with part G3 of the current building
regulations should be used. Installation
should be carried out generally as shown
on the following diagram.
1) Manual gas valve
2) Stop valve
3) Expansion vessel
4) T&P safety valve
5) Non return valve
6) Circulation pump
7) Drain valve
8) Pressure reducing valve
9) Expansion valve
Figur 5 - Connection diagram unvented systems
A) Gas supply
B) Hot water outlet
C) Cold water inlet
D) Hot water taps
E) Return circulation
AOS 1119

15
2.1.3 Gas connection
The gas supply to this appliance must
be installed in accordance with BS 6891
(1988) and British Gas Publications UP1
and UP2.
Fit the 1/2” gas supply cock supplied
with this unit immediately before the
gas control. No heat or soldered joints
should be applied in the vicinity of the
gas control, as they could cause damage
to the control. All connections and joints
should be tested for gas soundness with
a suitable leak detector (do not use a
naked ame).
N.B. When operating this unit on LPG a
suitable gas supply cock should be used.
2.1.4 Flue system
The water heater should be tted with
a ue system connected to the draught
diverter. The ue pipe should rise for at
least 50 cm. vertically before the inclusion
of any bends. If a horizontal run of ue
is required this should be kept to the
minimum lenght possible and incorporate
a rise of 6 cm. per metre of run. A split clip
or ange should be provided in the ue
close to the draught diverter for ease of
servicing.
All ue materials should be corrosion
resident i.e. stainless steel or galvanised
and must include a tested and apprved
terminal to BS 5440 part 1.
If the ue passes through any combustible
marerial measures must be taken to
protect against the possibility of re.
All ues must terminate in free air space
approx. 1,5 metres from any vertical
surface of structure i.e. chimney stacks,
roof parapets, etc. If an existing chimney
or ue is to be used this should be swept
clean and be free of debris before an
approved liner is installed and connected
to the water heater.
2.1.5 Draught diverter
The appliance has been tted with a
ue down draught safety device. The
operation of the safeguard is based
on the principle of the Thermal Reux
Safeguard (TRS).
This TRS can be recognized by the
copper coloured spiral that is tted to the
lower edge of the draught diverter. The
spiral is connected to a thermostat by
means of a capillary tube. The wiring of
the thermostat must be connected to the
thermocouple circuit.
Important
The TRS should never be put out of
operation. The reentry of ue gasses
may cause poisoning.
2.1.6 Electrical connection
All electrical connections must be carried
out in accordance with IEE regulations
by an accredited electrical installation
company. The appliance must be
connected to the mains by means of a
permanent electrical connection.
A main switch must be tted in the phase
between the permanent connection and
the water heater. The feeder cable must
have cores of at least 3 * 1.0 mm2The
connecting clamps for the electricity supply
are indicated by the symbol for earth Á,
N for neutral and L for live. Always check
with a voltage tester if the live and the
neutral have been connected correctly in
the electricity supply. The electricity supply
must comply with the requirements below:
Electrical Frequency Electrically
supply fused to a
minimum of
220/240 V AC 50 Hz 5A
The maximum power consumption is 25 W
See electrical diagram for more
information, appendix 1.

16
2.2 Commissioning
2.2.1 Filling the water heater
1. Close the drain tap.
2. Open the cold water tap to the water
heater and open all taps where hot
water can be drained for de aeration.
The water heater is lled as soon as
cold water ows from all taps.
3. Close all hot water taps.
2.2.2 Putting into operation
1. Check to see if the heater is lled
with water by running a little to waste
from a hot water tap connected to the
heater.
2. Check wether the ON/OFF switch is
in OFF-position.
3. Ensure gas supply is fully purged of
air and turn on gas cock.
4. Ensure that power has been correctly
supplied to the unit. Use a voltage
tester to check that the live is to “L”
and neutral to “N”. (Flame detection is
phase sensitive).
5. When rst starting, the controller can
be in the lock out condition: depress
the reset button to free the control.
(After manual reset, an extended
prepurge/waiting time will occur).
6. Switch the ON/OFF switch into ON
position. If the pilot fails to ignite
within 25 seconds the controls will go
to lock out and the reset button will
need to be reset (wait 15 seconds
before attempting reset). It may be
necessary to repeat the lighting
sequence a number of times on the
initial light up if all the air has not
been purged from the gas supply.
7. The main burner pressure has been
factory set but should be checked
once normal operation is established
(see ‘Ratings’ for settings).
8. Set the temperature regulator
to the required setting (see
‘Descalcication’).
Note: If during normal use the reset
button is pressed the gas valves
will close and the automatic ignition
controller will start a new sequence after
releasing the reset button.
2.2.3 Shut down
Note:The water heater should only be
turned off when hot water will not be
required for an extended period (e.g.
holidays); otherwise it should be left on.
To shut down put the ON/OFF switch into
OFF position.

17
2.3 Removing and
replacing the control
panel front cover
Removing the cover (see gure 7)
1. Remove the screw at the top centre of
the control panel.
2. Push the cover upwards until the
hooks at the lower end clear the
burner access opening and base tray.
3. Pull the lower end of the cover slightly
forward.
4. Pull the cover down until the top edge
is clear of the control panel and then
remove.
Replacing the cover (see gure 7)
1. Place the top of the cover inside the
rim of the control panel and push it up
as far as possible.
2. Position the bottom hooks inside the
burner access opening and over the
rim of the base tray.
3. Push the cover downwards until the
lower hooks engage and the top
screw holes align.
4. Replace the screw in the top centre
of the cover.
2.4 Setting the gas pressure
The gas pressure has been set to the
correct values at the factory.
Important: The following procedure
must be followed when checking or
setting the gas pressure:
1. Shut down the heater by switching
off the mains current (switch off main
switch);
2. Connect a manometer to the pressure
test nipple to measure the burner
pressure on the gas control.
3. Activate the heater and allow the
burner to ignite;
4. Check the burner pressure. If
necessary, reset it by means of the
burner pressure adjusting screw.
Turning it anti-clockwise reduces
burner pressure. Turning it clockwise
increases burner pressure;
5. Shut down the heater, remove the
manometer and close the pressure
nipple;
6. Restart the heater (test for
soundness).
Figur 7 taking off and mounting the
control panel
AOS 1130

18
2.5 Temperature regulation
The appliance is under water supply
pressure (maximum 8 bar). The amount
of cold water that is added is equal to
the amount of hot water used. The gas
control block automatically regulates the
gas supply. The main burner will ignite as
soon as a reduction in water temperature
is sended by the thermostat. The main
burner will shut down as soon as the
preset temperature is achieved.
At high water temperatures there is more
scale buildup in the appliance. It is for
this reason that it is recommended to
place the temperature control knob in
position of
60 °C as the accumulation of scale will
be reduced.
2.6 Converting to another
type of gas
For conversion of the appliance from
natural gas to another type of gas, or
visa versa, it is necessary to exchange
the pilot injector and the main injector.
The conversion may only be executed by
a qualed competent person.
Procedure:
1. Shut the heater down. Close the main
inlet gas valve and switch off the
electricity supply at the main switch;
2. Remove the burner assembly;
3. Replace the injectors with the correct
injectors from the conversion set.
(see table below).
Remark:
- When conversion of the appliance
from natural gas to another type of
gas, x the screw on the gas block
of the burner pressure control as
far as the stop.
- When conversion of the appliance
from another type of gas to natural
gas, then the right burner pressure
should be adjust.

19
2.7 Maintenance
To ensure safe and efcient operation of
the water heater it is recommended that
it is cleaned and serviced at least once a
year by a qualied competent person.
2.7.1 Magenesium anode
The life cycle of the anode is determined
by the quality and the quantity of the
water owing through the water heater.
It is therefore recommended that the
anode be inspected and replaced if
necessary at least once a year.
1. Close the stop cock in the cold water
supply pipe;
2. Open the nearest hot water tap in
order to allow the pressure to drop
from the water heater and the pipes;
3. Slacken the anode with a tting
wrench;
4. Check the anode and replace it if it
has been reduced in diameter by 60%
or more at any point on its lenght;
5. Check for water leaks.
If is necessary to replace the anode it
should be replaced by one of the same
type. The type of anode required can be
detemined on the basis of the type of the
appliance and the serial number.
2.7.2 Cleaning
1. Close the gas supply and demount
the burner after it has cooled down
2. Disconnect the burner assembly from
the gas control
3. Remove the complete burrner
assembly
4. Clean the burner with a soft brush
5. Check the pilot burner and clean it if
so required
6. Check the combustion chamber, ue
tube and ue bafe and clean these if
required
After cleaning of the pilot- and main
burner the operation of these should
be checked. If necessary the burner
pressure should be reset.
2.7.3 Decalcication
Formation of lime scale depends on the
quality and quantity of the water used.
In addition higher water temperatures
lead to more deposit in the appliance.
A temperature setting of 60° C is
recommended in order to keep the
calcication at a low level. Decalcication
should be attempted with the proper
means. For extensive information a
decalcication instruction is available.
2.7.4 Spare parts
To be able to order spare parts it is
important to note the type of appliance
as well as the serial number of the
appliance. Based on this information the
data concerning the spare parts can be
determined.
Description unit BTI 65
G20 G30 G31
Supply pressure mbar 20 30 37
Burner pressure mbar 12.0 - -
Diameter main injector mm 3.40 1.90 1.90
Diameter pilot injector mm 0.56/0.41 0.23 0.23

20
2.8 Inlet combination
Not applicable in U.K. and Ireland.
2.9 Gas smell
Immediately shut the main gas tap. Do
not light any re or switch o any lights,
do not use any electrical switches or
alarm bells. Open windows. Thoroughly
inspect all gas connections and, if the
gas smell persists, alert the local gas
company and/or your installer.
2.10 Condensation
If the appliance is lled with cold water or
if the hot water consumption is very high,
condensation of ue gasses will occur
on the cold surfaces of the combustion
chamber and the ue tube. The water
drops will fall on the burner and cause
a sizzling noise. This is a normal
phenomenon that will disappear as soon
as the appliance reaches its normal
operating temperature.
Important warning
The applicance should never be
taken into operation with a closed
cold water supply!
Provision should always be made for
expansion.