AO Smith Water Heater BFM 30 User Manual

MODELS  
BFM 30  
BFM 50  
BFM 80  
INSTALLATION INSTRUCTIONS AND  
USERS MANUAL  
UNITED KINGDOM  
CLOSED COMBUSTION WATER HEATER  
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CONTENTS  
PAGE  
1.  
1.1  
GENERAL  
Water heater description ..................................................................................................................... 5  
1.2  
Technical safety equipment ................................................................................................................ 6  
Gas control .......................................................................................................................................... 6  
Control box........................................................................................................................................... 6  
Burner automat ................................................................................................................................... .6  
Air proving switch ................................................................................................................................. 6  
Gas control valve ................................................................................................................................. 6  
Technical description .......................................................................................................................... 8  
Measurements .................................................................................................................................... 8  
Technical data ................................................................................................................................... 10  
1.2.1  
1.2.2  
1.2.3  
1.2.4  
1.2.5  
1.3  
1.3.1  
1.3.2  
2.  
FORTHEINSTALLER  
2.1  
Installation instructions ..................................................................................................................... 11  
Installation ......................................................................................................................................... 11  
Water connection ............................................................................................................................... 11  
Condensation drain........................................................................................................................... 14  
Gas connection ................................................................................................................................. 14  
Flue connection (concentric) ............................................................................................................. 14  
Electrical connection ......................................................................................................................... 16  
Turning the water heater on .............................................................................................................. 19  
Filling the water heater ..................................................................................................................... .19  
Turning the water heater on .............................................................................................................. 19  
Setting up the pilot flame ................................................................................................................... 19  
Turning the water heater off............................................................................................................... 19  
Usage/temperature control ............................................................................................................... 19  
Checking the gas pressures ............................................................................................................ 20  
Conversion to another gas ................................................................................................................ 21  
Maintenance ...................................................................................................................................... 22  
Anode ................................................................................................................................................. 22  
Descale procedure ............................................................................................................................ 22  
Condensation .................................................................................................................................... 23  
Spare parts ........................................................................................................................................ 23  
2.1.1  
2.1.2  
2.1.3  
2.1.4  
2.1.5  
2.1.6  
2.2  
2.2.1  
2.2.2  
2.2.3  
2.3  
2.4  
2.5  
2.6  
2.7  
2.8  
2.9  
2.10  
2.11  
3.  
FORTHEUSER  
3.1  
Instructions for use ............................................................................................................................ 24  
Warning ............................................................................................................................................. 24  
Filling the water heater ...................................................................................................................... 24  
Turning the water heater on .............................................................................................................. 24  
Usage ................................................................................................................................................ 24  
Turning the water heater off............................................................................................................... 24  
Maintenance ...................................................................................................................................... 24  
3.1.1  
3.1.2  
3.1.3  
3.2  
3.3  
3.4  
4.  
FAULTFINDINGANDCORRECTION  
4.1  
4.2  
4.3  
Fault finding userl .............................................................................................................................. 25  
Fault finding installer ......................................................................................................................... 26  
Detailed fault finding installer............................................................................................................ 27  
5.  
WARRANTY  
5.1  
5.2  
5.3  
5.4  
5.5  
5.6  
5.7  
Guarantee in general ........................................................................................................................ 31  
Guarantee of the tank ........................................................................................................................ 31  
Conditions for installation and use ................................................................................................... 31  
Exclusions ......................................................................................................................................... 31  
Range of the guarantee..................................................................................................................... 31  
Claims ............................................................................................................................................... 31  
No other guarantee or warranty either expressed or implied is  
made on behalf of A.O. Smith Water Products Company................................................................. 31  
3
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Figure 1  
1) TOP-BOX  
9) VENTILATIONFAN  
10) ANODE  
11) FLUE TUBES  
12) FLUE BAFFLE  
13) DIAPHRAGM  
2) AIRPROVINGSWITCH  
3) TEMPERATUREREGULATOR  
ON/OFFSWITCH  
RESET-KNOB  
4) BURNER CONTROLLER  
5) GASVALVE  
14) INSULATION  
15) BURNER  
6) MANIFOLD/INJECTORS  
7) PILOT BURNER  
16) AIRDIFFUSIONPLATE  
17) CONDENSATE DRAIN  
8) HORIZONTALAIRINLET  
4
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1. GENERAL  
1.1 Description of the appliance  
Construction and fitting out of the storage appliance  
comply with the European Standard for gas fired hot  
water storage appliances for sanitary use (EN89). The  
appliance thereby satisfies the requirements of the  
European Directive for Gas Appliances, and is therefore  
entitled to bear the CE mark.  
The BFM appliance is an enclosed appliance with a  
fan in the air inlet ( appliance category C or C ). The  
13  
33  
appliance is designed for a concentric flue  
configuration. A diaphragm, across which the pressure  
difference can be measured, is fitted in the air inlet  
system. When the control thermostat calls for heat, the  
burner control unit carries out a zero position check. The  
fan is subsequently switched on and, at a signal from  
the pressure difference switch, the pre-ventilation  
period (minimally 30 seconds) commences. Following  
the pre-ventilation period the burner control unit  
switches on the ignition transformer whereby the first  
gas valve (the pilot) opens. On receiving an ionisation  
signal from the ignition burner, the second (main  
burner) gas valve opens. The appliance is now in  
operation.  
Technically this appliance falls into gas category  
II  
; the appliance is therefore suitable for natural  
2L3P  
gas as well as propane and butane gases. The storage  
appliance is suitable for working pressures to 8 bar. A  
connection is provided for the optional fitting of an extra  
safety feature, the temperature and pressure valve. The  
interior of the tank is enamelled for corrosion protection,  
and a number of magnesium anodes are fitted to the  
tank for the same purpose.  
A thick polyurethane insulating layer between the tank  
and its steel casing prevents unnecessary heat loss. If  
the storage appliance is completely filled with water it is  
under continual mains pressure. When hot water is  
tapped off the appliance, cold water is immediately  
introduced. Turbulence strips are placed in the fire tu-  
bes for the efficient transfer of heat. The flue gases pass  
their heat to the water by conduction and radiation. The  
flue gases are led to the flue via the top box. The burner  
bed consists of a number of bar burners. An injector is  
screwed into the manifold ahead of each burner, which  
ensures correct mixing of gas and primary air through  
injection into the burner inlet venturi. Secondary air is  
drawn between the bar burners. An air distribution plate,  
which also functions as a radiant heat shield, is fitted  
below the burners. Any condensation water produced is  
captured beneath the combustion chamber and led  
away via a siphon (see illustration 1).  
5
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1.2 Technical safety equipment  
continues to work.  
-
An interlocking of the burner automation can be  
cancelled out by pressing the reset knob. If the  
procedure does not succeed immediately, wait at  
least 15 seconds before pressing the interlocking  
knob again.  
1.2.1 Gascontrol  
The water heaters are equipped with a gas control  
valve which regulates the flow of gas to the burner. The  
combination gas control is equipped with a safety valve,  
gas control valve, pilot safety valve and burner control  
(on a standard natural gas setting)  
If the flame detection falls out during normal  
operation, the burner automation will automatically  
repeat its ignition procedure. As long as a flame is  
detected within the safety period of 50 seconds, the  
automation will continue to repeat the ignition proce-  
dure.  
1.2.2 Control box  
For safety purposes, water heaters are always fitted  
with three thermostats: a control thermostat, a high-limit  
thermostat and an overheat thermostat.  
The desired water temperature is set with the control  
thermostat. To protect against freezing, the control  
thermostat is also fitted with frost protection which  
ignites the burner when the water temperature drops to  
20oC, irrespective of the thermostat’s temperature  
setting. The overheat thermostat prevents the water  
reaching too high a temperature.  
As soon as the water temperature has reached the  
set value, the burner automation will close the gas  
valves.  
The control column has a potential-free contact for  
external error message.  
Should both control and high-limit thermostats  
malfunction, the overheat thermostat will automatically  
shut down the water heater.  
1.2.3. Ventilation fan  
The ventilation fan is installed in the top-box. When  
heat is required the ventilation fan is switched on by the  
burner automation. The fan switches off when the main  
burner has extinguished. The fan can be removed from  
the top box via the access panel.  
The control thermostat can be set at settings 1-4  
(approx. 40°C to 73°C). The frost protection ignites the  
burner if the water temperature drops below 20°C. The  
switch temperature of the high-limit thermostat is 84°C;  
the overheat thermostat cuts in at 93°C. The sensor for  
the control/frost thermostat is located at the level of the  
control switch; the sensors for the high-limit and  
overheat thermostats are located near the top of the  
water heater.  
The control box is fitted with an ON/OFF switch (I/0).  
At setting I, the gas control operates on the basis of heat  
demand from the control thermostat. At setting 0 the  
water heater is switched off. The burner will only ignite  
on the basis of heat demand from the frost protection.  
1.2.4 Air proving switch  
The air proving switch ensures that there is sufficient  
air flow for the safe operation of the water heater. If the  
airflow falls below the preset value this will be detected  
by the air proving switch and the gas supply to both the  
ignition and main burners will be closed. The air proving  
switch is preset and cannot be adjusted.  
Air proving switches BFM-units  
Unit  
Pstart  
(Pa)  
250  
250  
230  
Poff  
(Pa)  
220  
220  
205  
BFM 30  
BFM 50  
BFM 80  
When the control thermostat calls for heat, the water  
heater checks all controls are in the off position. Power  
is then switched to the ventilation fan. Immediately the  
air pressure switch opens. The purge cycle starts. This  
runs for between 30 and 60 seconds after which the  
safety valve opens and the spark generator is operated.  
The air proving switch must always be fitted with the  
connection points downwards!  
The air pressure differential switch must always be fitted  
with the connection points at the bottom, while the pipe  
with the letter H must be connected to the point P1. Pipe  
L goes to connection P2.  
Gas flows to the pilot burner where it is ignited by the  
spark generator. The ionization probe now detects the  
flame, switches off power to the spark generator and  
opens the main gas valve.A softlite staged ignition  
control prevents explosive ignition by allowing a small  
percentage of total gas rate into the combustion  
chamber initially followed by the full rate when  
combustion is established. When the water temperature  
reaches the set point the water heater is turned off.  
If the flame extinguishes whilst in operation both the  
safety (pilot) valve and the gas valve will close  
immediately. If the control thermostat is still calling for  
heat the burner automation will repeat the ignition  
procedure.  
1.2.5 Gascontrol  
The water heaters are provided with a gas valve that  
regulates the gas supply to the burners.  
The gas control has a safety valve and a gas valve  
and hence has a B/D-configuration. The position of both  
valves can be regulated by the burner automation. To  
ensure improved ignition the gas control valve opening  
mechanism is fitted with a delay (softlite).  
-
-
If no flame is detected within the safety time of  
50 seconds, the burner automation will interlock and  
the reset knob will light up.  
As long as the air proving switch does not operate  
(remains closed), the burner automation will remain  
in the waiting position, while the ventilation fan  
6
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Figure 2 - Positioning ventilation  
Figure 3 - Differential pressure switch  
7
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1.3 Technical description  
1.3.1 Measurements  
See figure 4  
Size  
BFM30  
BFM50  
BFM80  
A
B
C
D
E
F
G
H
K
L
1995  
1795  
600  
1995  
2020  
1820  
600  
1795  
600  
520  
520  
525  
600  
600  
590  
1640  
1360  
630  
1640  
1655  
1360  
625  
1360  
630  
710  
710  
710  
1000  
755  
1000  
1000  
755  
M
N
1
755  
80/125  
100/150  
130/200  
Cold water inletRP1½  
Hot water outletRP 1½  
Gas valve RP ¾  
Drain valve ¾"-14 NPT  
2
3
4
5
T&P-connection (temperature- and pressure valve) 1"-14 NPT  
All dimensions in mm, rounded up to the nearest 5 mm.  
8
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IM D-0057-R0  
Figure 4  
9
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1.3.2 Technical data  
Heater category:II  
2H3+  
Description  
Unit  
BFM30  
BFM50  
BFM80  
DATANATURALGASG20  
Nominal gas inlet pressure  
Burner pressure  
mbar  
mbar  
kW  
20  
12.5  
29  
20  
12.5  
47  
20  
12.5  
75  
Input  
Output to water  
kW  
27  
42  
68  
Gas consumption*  
Diameter main injector  
Diameter injector ignition burner  
Heating time T=45°C  
m3/h  
mm  
mm  
min  
3.0  
4.7  
7.9  
2.60  
0.56 / 0.41  
35  
2.50  
0.56 / 0.41  
25  
2.70  
0.56 / 0.41  
12  
DATAPROPANE/BUTANEG30-G31  
Nominal gas inlet pressure  
Input  
G30  
G31  
37  
G30  
30  
G31  
G30  
G31  
37  
mbar  
kW  
30  
29  
37  
44  
30  
75  
28  
46  
71  
Gas consumption  
kg/h  
mm  
mm  
2.3  
2.1  
3.6  
3.3  
5.8  
5.3  
Diameter main injector  
Diameter injector ignition burner  
1.45  
0.25  
1.40  
0.25  
1.50  
0.25  
GENERAL  
Storage capacity  
Number of bar burners  
Number of anodes  
Number of flue tubes  
Water connections  
Gas connection  
Drain connection  
Anode  
litre  
309  
298  
253  
-
3
2
5
5
2
7
7
-
4
-
16  
-
-
Rp11/2  
Rp3/4  
Rp11/2  
Rp3/4  
Rp11/2  
Rp3/4  
-
3/4" - 14 NPT  
3/4" - 14 NPT  
1” - 14 NPT  
8
3/4" - 14 NPT  
3/4" - 14 NPT  
1” - 14 NPT  
8
3/4" - 14 NPT  
3/4" - 14 NPT  
1” - 14 NPT  
8
-
Connection T&P-plug**  
Maximum working heat  
Empty weight  
-
bar  
kg  
270  
290  
350  
*
Gas usage at 1013,25 mbar and 15 °C.  
** For a leak-tight connection European coupling pieces with pipe screw-thread according to ISO 228/1 or ISO 7/1 can be  
used on the NPT-connection nipples.  
10  
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2.1.2 Water connections  
2. FOR THE INSTALLER  
A.O. Smith water heaters are suitable for connection  
to vented, unvented and pumped pressurised systems.  
In each case appropriate valves and fittings should be  
used to ensure the system complies with the  
requirements of the water by laws, and appropriate  
building regulations.  
If possible, use a trolley or fork-lift truck to move the  
water heater. Always move the water heater in an upright  
position.  
2.1 Installation instructions  
When fitting it is essential the rules of 'good practice'  
are applied at all stages of installation.  
The following distances should be observed:  
Vented systems  
-
Sides of the water heater:  
(free space for the accessibility of the  
hand holes)  
Rear of the water heater:  
Around top-box and concentric pipe:  
Front of the water heater:  
100 cm  
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. See diagram 5.  
-
-
-
15 cm  
15 cm  
100 cm  
(free space to take out bar burners)  
2.1.1 Installation  
A.O. Smith water heaters are tested to a maximum  
pressure of 12 bar and a maximum working pressure of  
8 bar.  
Installation should be carried out in accordance with  
all local authority and building regulations, local water  
authority and fire regulations and the following British  
standards: British Gas Publication UP1 and UP2.  
Dead legs on a hot water installation are  
undesireable. Where possible they should be avoided.  
Where the inclusion on the system of a dead leg is  
unavoidable the following restrictions should be  
applied:  
BS 5482  
part 1 1979  
part 2 1979  
part 3 1979  
BS 6644  
BS 6700  
BS 6798  
-
for pipes not exceeding 19 mm. inside diameter;  
maximum lengh of dead leg permitted 12.0 metres;  
for pipes exceeding 19 mm. but not exceeding 25  
mm. inside diameter; maximum length of dead leg  
7.5 metres;  
-
-
for pipes with an inside diameter exceeding 25 mm.  
maximum dead leg 3.0 metres.  
1) Gas cock  
2) Stop valve  
3) Three way vent valve  
4) T&Pvalve  
5) Non-return valve  
6) Circulation pump  
7) Drain valve  
A) Gas supply  
B) Hot Water  
C) Cold Water  
IM D-0065  
D) Overflow  
E) Return circulation  
Diagram 5 - Typical UK vented system  
11  
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Depending on the length and insulation of the water  
piping and the water demand frequency, it may be  
necessary to install a circulation system on the drain  
cock. The return pipe of the circulation piping can be  
fitted on the top of the drain cock after the sealing plug  
has been removed (see figure 6).  
Unvented  
To install an A.O. Smith water heater on an unvented  
cold water supply system a kit of valves and fittings  
listed by the water research centre and complying with  
part G3 of the current building regulations and BS 7206  
should be used. Installation should be carried out  
generally as shown on diagram 7. Kits are available  
from A.O. Smith or our distributors.  
1) Gas cock  
2) Stop valve  
3) Expansion vessel  
4) T&Pvalve  
Figure 6  
5) Non-return valve  
6) Circulation pump  
7) Drain valve  
8) Pressure limiting valve  
9) Expansion valve  
A) Gas supply  
B) Hot water  
C) Cold water  
D) Hot water supply  
E) Return circulation  
IM D-0066-R0  
Diagram 7 - Connection diagram (unvented system)  
12  
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Depending on the water demand pattern (e.g., small  
amounts frequently), it may be necessary to circulate the  
water in the water heater to prevent temperature  
stratification. Therefore, we recommend that a  
circulation system is installed in the event of such  
demand patterns (see figure 8). Kits are available from  
A.O. Smith or our distributors.  
1) Pump (type: Grundfos  
UP 20-15 N150, or similar)  
2) Non-return valve  
3) Gate valve  
4) Drain valve  
5) Gas valve  
A) Cold Water  
B) Hot Water  
C) Return circulation pipe  
D) Gas supply  
IM D-0059  
Figure 8 - Connection diagram including destratification  
circulation system  
13  
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2.1.3 Condensation drain  
In order to guarantee the correct operation of the  
water heater, the condensate drain of the water heater  
must open into the sewer interrupted, provided with an  
extra stench trap or siphon. A condensation drain  
section fixed to the water heater should be fitted under  
the slope. The condensate drain of the water heater  
must never be sealed.  
2.1.4 Gasconnection  
The gas installation may only be carried out by a  
registered installer and in accordance with the relevant  
local authority and building regulations and followint  
British standards.  
2.1.5 Flueconnections(concentric)  
The combined flue discharge and air intake tubes  
(concentric) should always be assembled with a rising  
slope towards the flue terminal, and in accordance with  
the table below.  
IM D-0060  
figure 9  
-
Wall configuration (see figure 9)  
Type:  
M2000 MDV SE  
Meulink & Grol  
Thick-walled aluminium with lip ring seal.  
Thin-walled galvanised steel plate.  
Ø 80 / 125 mm  
Manufacturer:  
Pipe material flue tube:  
Pipe material air supply:  
Pipe diameter BFM 30:  
BFM 50:  
Ø 100 / 150 mm  
BFM 80:  
Ø 130 / 200 mm  
Angle:  
90° (2 max.)  
Flueconfiguration/horizonaldischargeBFM-unit  
Measurement  
BFM 30  
BFM 50  
BFM 80  
min.  
max.  
7000  
7000  
min.  
max.  
7000  
7000  
min.  
max.  
A
0
0
0
0
0
0
7000  
7000  
B
A+B  
< 7000  
< 7000  
< 7000  
All measurements are in mm.  
The following applies for the horizontal pipe: slope of at least 5 mm per metre of pipe to the water heater.  
NB. Measurements A + B are the total permissible dimensions of the flue, i.e. when A = 1 metre, B = 6 metres (total 7  
metres) or A = 4 metres, B = 3 metres (total 7 metres).  
14  
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-
Roof discharge (see figures 10 and 11).  
Type:  
M2000 DDV SE HR/VR  
Meulink & Grol  
Thick-walled aluminium with lip ring seal.  
Thin-walled galvanised steel plate.  
Ø 80 / 125 mm  
Manufacturer:  
Pipe material flue tube:  
Pipe material air supply:  
Pipe diameter BFM 30:  
BFM 50:  
Ø 100 / 150 mm  
BFM 80:  
Ø 130 / 200 mm  
Angle:  
45°/90° (max 2)  
FlueconfigurationsroofdischargeBFM-unit  
Measurement  
BFM 30  
BFM 50  
BFM 80  
min.  
max.  
7000  
7000  
min.  
max.  
7000  
7000  
min.  
max.  
A
0
0
0
0
0
0
7000  
7000  
B
A+B  
< 7000  
< 7000  
< 7000  
these flue configurations.  
All measurements are in mm.  
These will each equate to 1 metre of flue length.  
The following applies for the horizontal pipe: slope of at  
least 5 mm per metre of pipe to the water heater.  
A maximum of 2 bends (45° or 90°) may be used with  
The maximum flue configuration is therefore 7000 mm  
pipe, 2 bends (45°/90°) and a lead-through set.  
IM D-0061  
IM D-0062  
Figure 10 and 11 - Roof discharge.  
15  
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2.1.6 Electrical connection  
All electrical connections must be carried out by a  
registered electrical contractor to the relevant  
regulations.  
The BFM must be connected to a supply voltage by  
means of a permanent electric connection and have a  
feeder cable not less than 3 x 1,0 mm².  
Supply voltage  
220/240 VAC  
Supply network  
frequency  
Mínimum fuse  
required  
50 Hz  
1 A  
The electrical diagram of the BFM-heater and the  
connections in the control-column are shown in figures  
12 and 13.  
Electrical connection diagram BFM  
(see figure 12)  
A) Jacket  
B) Transformer 230V/238V/2VA  
C) Air proving switch  
D) EMC single phase filter  
E) RESET knob  
F) Thermostat frost  
G) Thermostat regulation  
H) Switch ON/OFF  
K) Thermostat overheat 93°C  
L) Thermostat high limit 84°C  
M) Automatic burner controller  
N) Plastic connector strip  
P) Earth terminal block  
S) Relais  
Colour-codecables:  
1 Blue  
2 Brown  
3 Yellow/green  
4 Red  
5 White  
6 White/orange  
7 White/violet  
8 Black  
9 Black/green  
10 Black/red  
11 Black/white  
16  
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IM D 0055 R1  
Figure 12 - Electrical connection diagram BFM  
17  
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IM D-0063  
Figure 13 - Connection diagram control-column.  
D) Transformer 230  
E) Air proving switch  
F) EMC single phase filter  
G) RESET knob  
M) Thermostat overheat  
N) Thermostat high limit  
P) Automatic burner controller  
R) Relay  
H) Thermostat frost  
K) Thermostat regulation  
L) Switch ON/OFF  
X) Plastic connector strip  
Y) Earth terminal block  
18  
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2.2 Turning the water heater on  
The position of the temperature control knob  
coincides with the following temperatures:  
Position 1 = app. 40°C  
2.2.1 Filling the water heater  
1. Assemble the drain-off tap and check that it is closed.  
2. Open the cold water tap to the water heater and open  
all taps on hot water outlet points to vent them. The  
heater is filled as soon as cold water pours out of  
all outlet points.  
3. Close all taps at hot water draining points. The  
heater is now under water supply pressure. At  
this pressure, the relief valve if fitted may not release  
water.  
Position 2 = app. 50°C  
Position 3 = app. 60°C  
Position 4 = app. 70°C  
At high temperatures, more calcium precipitation is  
caused in the water heater. Moreover, the standby-  
losses of the water heater are greater with higher  
temperatures. It is recommended to set the control-  
thermostat at approximately 60°C. For reasons of  
security, the water heater is provided with a high limit  
and safety thermostats. The high limit thermostat is an  
extra control set at 80°C and will operate in the event of  
excess temperature within the water heater.  
2.2.2 Turning the water heater on  
1. Check whether the water heater is filled with water  
andwhether the gas pipe to the water heater is open.  
2. Vent the gas pipe by opening the pressure gauge  
nipple at the inlet side of the gas valve. Close the  
pressure gauge nipple as soon as the gas pipe has  
been vented.  
If the safety thermostat operates, the ‘RESET’ button  
must be pressed after the water has cooled down. The  
water heater will operate again in the usual manner.  
3. Turn the temperature control knob fully to the left.  
4. Turn on- the supply voltage by turning the main  
switch. NOTE: if the frost-thermostat is calling for heat  
the burner automation will immediately start its  
ignition procedure.  
5. Turn the ‘I/O’-switch on the column to the ‘T’  
position. The control lamp in the switch will light.  
6. Turn the temperature control switch to the desired  
position, preferably position 3 (approximately 60°C).  
The burner will ignite; the water heater will now work  
automatically.  
7. Check the standing pressure with a manometer  
which can be connected to the pressure gauge  
nipple. Check that the working pressure is set to the  
correct level (see table page 10).  
2.2.3 Setting up the pilot flame  
The pilot flame has been adjusted in the factory and  
does not have to be checked.  
2.3 Turning the water heater off  
For short periods:  
1. Turn the temperature knob fully to the left and turn the  
‘I/O’-switch in the ‘O’-position.  
For longer periods:  
1. Switch off the supply voltage.  
2. Close the gas tap in the supply line.  
3. Close the water supply tap.  
4. If there is danger of frost, drain the water heater.  
2.4 Usage/temperature control  
The water temperature is controlled via the  
temperature regulator. If the temperature in the water  
heater falls below the set value, the temperature  
regulator will call for heat. The burner automation will  
operate firstly the ventilation fan for its purge cycle, then  
a spark will ignite the pilot burner. The softlite control  
then ignites the main burner.  
19  
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2.5 Checking the gas pressures  
2. Connect the U-tube manometer to pressure nipple B.  
3. Switch on main power and ensure temperature  
control is calling for heat.  
4. Wait until water heater is firing.  
5. Check pressure against table on page 10 for relevant  
gas and adjust at main gas valve.  
The nominal load has been set at the correct value in  
the factory. A further check of the pressure should be  
carried out during the commissioning of the unit.  
A dangerous situation can occur if the following  
instructions are not followed carefully. Setting the  
nominal load is possible as there is a burner pressure  
control. If you wish to adjust the burner pressure the  
following procedures must be followed:  
6. Switch of main power as no. Y.  
7. Remove U-tube manometer and close pressure  
nipple.  
8. Switch on main power and test for gas tightness and  
correct operation, (Figure 14).  
1. Switch off main power by turning the I/O switch to ‘0’  
position.  
Figure 14 - Checking the gas pressures  
20  
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2.6 Conversion to another gas  
Important: Install a gas valve suitable for the type of  
gas to be used.  
If the water heater has to function on a gas category (LP  
or natural gas) other than the gas set as standard (ex  
works), the water heater must be converted to the  
applicable gas category with the associated conversion  
kit(s).  
Only an accredited installer may convert the heater.  
All the injectors of the main burner bars and the injector  
of the ignition pilot must be replaced.  
Regurlary natural gas units do have a burner pressure  
regulator, but LP-gas units do not.  
The burner pressure regulator on the gas control must  
be removed when converting the heater for use on LP-  
gas (if present).  
AOS 0546  
The burner pressure regulator must be fitted on the gas  
control when converting to natural gas (if required)  
The table with technical data shows which injectors  
must be fitted for the gas category in question.  
Figure 15 - mounting covering plate with sealing on the  
gas valve  
Procedure:  
1. Shut the water heater down; close the main inlet  
gas valve and switch of the electricity supply at the  
main switch;  
2. Remove the burner tray including the gas valve:  
a. remove the screws of the burner tray housing,  
b. loosen the wiring of ingition and ionisation pen  
on the burner controller,  
c. loosen the gas control cable,  
d. dismount the gas supply to the gas valve;  
3. Remove the burner tray from underneath the heater;  
4. Replace the main injectors and the injector of the  
ignition burner. Use the table with technical data to  
check that the diameter of the injectors is correct;  
5. Converting from natural gas to LP-gas:  
a. remove the burner pressure regulator on the  
gas control,  
b. mount the flat covering plate with sealing  
provided in the conversion kit,  
c. see figure 15;  
AOS 547  
Converting from LP-gas to natural gas:  
a. remove the flat covering plate with sealing on the  
gas control,  
b. mount the burner pressure regulator on the gas  
valve,  
Figure 16 - mounting burner pressure regulator on the  
gas valve,  
c. See figure 16;  
6. Mount the burner tray;  
7. Reconnect the wiring and gas supply to the gas  
valve;  
8. Open the main inlet gasvalve;  
9. Check the gas inlet pressure;  
10. Switch on the electricity supply at the main switch;  
11. Commision the water heater;  
12. Adjust the burner pressure to the value as indicated  
in the technical data;  
13. Check the soundness;  
14. Check the operation of the heater;  
15. Fix the conversion sticker from the conversion kit  
below the rating plate to the heater, so that is clear  
on which gas category the heater operates.  
21  
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2.7 Maintenance  
The water heater must be checked and cleaned  
regularly (at least once a year) by an accredited installer,  
so that proper operation is guaranteed. The bar burners,  
control and safety valves must also be checked. (see  
figure 17).  
2.8 Anode  
The life of the anode is determined by the quality and  
the quantity of water flowing through the water heater.  
Therefore, we recommend that the anode is checked  
regularly - preferably simultaneously with an internal  
inspection of the enamelled tank. In order to determine  
the frequency with which the anodes must be replaced,  
the water side of the boiler must be checked three  
months after installation. The anodes must be replaced  
if more than 50% has dissolved at any point on their  
length.  
Procedure:  
1. Shut off the cold water supply tap.  
2. Completely empty the water heater by means of the  
draw-off tap. Remember to ventilate the water heater.  
3. Remove the sealing plates at the hand holes on the  
outer cover of the water heater.  
4. Open the hand holes and inspect the anodes. In  
order to guarantee a water-tight seal at the hand  
holes, the rubber O-rings must be replaced (see  
figure 18).  
If the anodes need replacing:  
1. Disassemble the concentric flue tube.  
2. Disassemble the electrical connection of the  
ventilation fan on the top-box.  
3. Loosen the fastening bolts of the top-box.  
4. Remove the top-box, the positioning of the anodes  
will now become visible (see figure 18).  
5. Loosen the anodes with suitable tools and replace  
with new ones. NOTE: the anodes must be in contact  
with the tank (metal on metal). For if the anodes and  
tank are electrically separated (as a result of the  
sealant used), the anode cannot perform its function.  
This can shorten the life-span of the tank.  
6. Assemble everything in reverse order.  
7. Fill the water heater.  
Figure 17  
2.9 Descale procedure  
Calcium deposition depends on the type of water  
and the demand. In addition, calcium deposition  
increases at high water temperatures. A temperature  
setting of 60°C is recommended, which will keep  
calcium deposition to a minimum.  
Inspection hatches are located on the right and left  
sides for inspecting and deliming the tank. The hand  
holes can be reached via the covering plates on the  
outer jacket.  
Empty the water heater before opening the  
inspection hatches. Deliming must be executed with the  
correct tools. Consult the supplier of the water heater or  
the installer on this matter. In order to guarantee a  
water-tight seal of the hand holes, the rubber O-rings in  
the hand holes must be replaced (see figure 17).  
Figure 18 - Maintenance anodes  
22  
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2.10 Condensation  
If the water heater has been filled with cold water or if  
the hot water usage has been very high, normally  
condensation of the flue gasses will occur on the cold  
sides of the combustion chamber and the flue tubes.  
The water drops will fall on to the burner bed which can  
cause a hissing sound. This is normal and will  
disappear as soon as the water heater has reached its  
operating temperature again.  
2.11 Spare parts  
To order spare parts, it is important to state the water  
heater type, model and the complete serial number.  
Figure 19 - Maintenance anodes  
23  
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3.3 Turning the water heater off  
3. FOR THE USER  
For short periods:  
1. Turn the temperature knob fully to the left and turn  
the ‘I/O’-switch in the ‘O’-position.  
3.1. Instructions for use  
Installation and commissioning of the water heater  
should only be undertaken by a registered installer.  
For longer periods:  
1. Switch off the supply voltage;  
2. Close the gas tap in the supply line;  
3. Close the water supply tap;  
3.1.2 Filling the water heater  
1. Assemble the drain-off tap and ensure it is closed;  
2. Open the cold water tap to the water heater and open  
all taps on hot water drain-off points to vent them.  
Theheater is filled as soon as cold water pours out of  
all drain-off points;  
3. Close all taps at hot water drain-off points. The  
heater is now under water supply pressure. At this  
pressure, the relief valve if fitted may not release  
water.  
4. If there is danger of frost, drain the water heater.  
3.4. Maintenance  
The water heater must be checked and cleaned  
regularly (at least once a year) by an accredited installer,  
so that proper operation is guaranteed. The bar burners,  
the pilot burner and the control and safety valves must  
also be checked.  
3.1.3 Turning the water heater on  
1. Check that the water heater is filled with water and  
that the gas pipe to the water heater is open;  
2. Turn the temperature control knob fully to the leftl;  
3. Turn on( the supply voltage by turning the main  
switch. NOTE: if the frost-thermostat has been  
turned on, the burner automation will immediately  
start its ignition procedure);  
4. Turn the ‘I/O’-switch on the column in the ‘T’ position.  
The control lamp in the switch will now light;  
5. Turn the temperature control switch in the desired  
position, preferably position 3 (approximately 60°C).  
The ventilation fan will start. the water heater will  
ignite and work automatically.  
3.2 Usage  
The water temperature is controlled via the  
temperature regulator. If the temperature in the water  
heater falls below the set value, the temperature  
regulator call for heat. The burner automation will  
operate firstly the ventilation fan for its purge cycle, then  
a spark will ignite the pilot burner. The softlite control  
then ignites the main burner.  
The temperature is indicated by the position of the  
temperature dial:  
Position 1 = app. 40°C  
Position 2 = app. 50°C  
Position 3 = app. 60°C  
Position 4 = app. 70°C  
At high temperatures, more calcium precipitation is  
caused in the water heater. Moreover, the standby-  
losses of the water heater are greater at higher  
temperatures. It is recommended that the control-  
thermostat be set at approximately 60°C. For reasons of  
security, the water heater is provided with a high limit  
and safety thermostats. If the high limit thermostat  
operates, the burner will not fire until the water has  
cooled sufficiently to allow the thermostat to  
automatically reset. The water heater will then return to  
the control of the temperature regulator.  
If the safety thermostat operates due to high  
temperature the ignition sequence must be repeated  
after resetting the control.  
24  
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4. FAULT FINDING  
4.1 Fault finding USER  
No or insufficient  
hot water.  
Check whether the  
electricity  
is turned on.  
Reduce the water use  
or increase the  
control thermostat.  
Check whether the  
gas supply is turned  
on.  
yes  
Does the  
ON/OFF switch light  
up?  
yes  
yes  
Is the  
water heater in  
operation?  
Does the  
RESETswitch light  
up?  
yes  
no  
Push RESET switch up  
Check if  
ON/OFF switch in  
position 1?  
yes  
to three times  
no  
no  
Is the  
water heater in  
operation?  
yes  
Problem  
solved  
Put  
ON/OFF switch in  
position 1?  
Is the  
yes  
Problem  
solved  
water heater in  
no  
operation?  
no  
Consultyourinstaller.  
25  
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4.2 Fault finding INSTALLER  
Check gas connection  
and the electricity  
supply make sure that  
they are switched on.  
Problem  
solved  
yes  
Does the  
yes  
Does the  
RESETswitch  
light up?  
Is the  
water heater in  
operation?  
no  
ON/OFFswitch  
light up?  
no  
Check if  
ON/OFF switch is in  
position 1?  
yes  
Push the  
RESETbutton  
up to three times  
no  
Put  
ON/OFF switch in  
position 1.  
no  
Is the  
water heater in  
operation?  
yes  
no  
Problem  
solved  
Is the  
water heater in  
operation?  
yes  
Problem  
solved  
no  
no  
See detailed fault finding  
26  
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4.3 Detailed fault finding INSTALLER  
Check  
voltage present  
no  
Reinstate voltage supply  
at connection 1.  
yes  
Check  
voltage present  
afterFILTER  
no  
Ensure connections correct,  
if yes replace FILTER  
yes  
Check  
voltage present at  
gate3ON/OFF  
switch  
no  
Ensure connections correct,  
if yes replace ON/OFF switch  
yes  
Check  
voltage present  
at gate 11 and 12  
CONTROL  
1. Check if controle thermostat is closed  
2. Ensure connections correct.  
3. IfyesreplaceCONTROLTHERMOSTAT.  
no  
THERMOSTAT.  
yes  
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yes  
Check  
Ensure connections correct,  
if yes replace  
MAXIMUMTHERMOSTAT  
voltage present at  
GATE12MAXIMUM  
THERMOSTAT?  
no  
no  
no  
no  
no  
yes  
Check  
voltage present at  
GATE1BURNER  
AUTOMATION  
S4560D 1150?  
Ensure connections correct,  
if yes replace  
BURNERAUTOMATION  
yes  
Check  
voltage present at  
GATE8BURNER  
AUTOMATION  
Replace  
BURNERAUTOMATION  
yes  
Ensure connections correct,  
if yes replace  
IsVENTILATINGFAN  
in operation?  
VENTILATINGFAN  
yes  
Ensure connections  
correct,  
Check  
Check  
Check  
voltage present at  
voltage present at  
GATE7,BURNER  
AUTOMATION  
no  
no  
voltage present at  
GATE1AIRPROVING  
SWITCH  
if yes replace  
BURNER  
AUTOMATION  
GATE3AIRPROVING  
SWITCH  
yes  
yes  
yes  
DISCONNECT  
GASSUPPLY  
Ensure connections correct  
yes  
Check  
no  
voltage present at  
GATE7,BURNER  
AUTOMATION  
Replace  
BURNERAUTOMATION  
Disconnect the pipe air  
supply by removing the  
elbow at the rear bottom.  
Measure pressure at  
hose H  
at the column.  
yes  
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yes  
Ensure connections  
correct, if yes  
check hose H for  
leakkage or blockings  
Check  
voltage present at  
GATE12ECO  
Pressure  
H higher then  
300 PA?  
no  
Ensure connections  
correct, if yes replace  
ECO  
no  
yes  
yes  
Measure pressure at  
hose  
Check  
voltage present at  
GATE11BURNER  
AUTOMATION  
no  
Ensure connections  
correct  
H at the column  
Ensure connections  
correct, if yes  
check hose L for  
no  
Pressure L less  
then 0 PA?  
leakkage or blockings  
yes  
yes  
Check exhaust system on  
blockings if the exhaust  
system is open, replace AIR  
PROVINGSWITCH  
Check  
Check  
no  
voltage present at  
GATE10BURNER  
AUTOMATION  
no  
Replace  
voltage present at  
GATE2BURNER  
AUTOMATION  
BURNERAUTOMATION  
yes  
yes  
Problem solved  
Ensure connections  
correct, if yes replace  
RESETswitch  
no  
Does the RESET  
switch light up?  
yes  
RESET the water heater  
and wait one cycle,  
advanced Fault Finding  
29  
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no  
no  
Water heater in  
in operation?  
Re-instate gas supply  
and reset water heater  
Gas supply  
present?  
yes  
yes  
IONISATIONPROBLEMS.  
Problem  
solved  
Carry out 3 RESET cycles to make  
sure the pilot is provided with gas.  
Check gasconnections towards the  
pilot burner. Carry out one more  
RESET cycle. If no operation is valid  
replace the entire PILOT BURNER  
assy. RESET water heater after  
replacing the PILOT BURNER  
Check  
voltage on  
no  
no  
Ensure connections  
correct  
Water heater  
in operation?  
PRIMARY CIRCUIT,  
TRANSFORMER  
yes  
yes  
Problem  
solved  
Check  
voltage on  
SECUNDARYCIRCUIT,  
no  
Ensure connections  
correct. If yes replace  
transformer  
TRANSFORMER  
yes  
Problem  
solved  
30  
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and laundries or where some industrial degreasing  
products are used and stored (for further  
information and advise please contact the  
A.O. Smith Technical Department).  
5. WARRANTY  
The following conditions form the guarantee agreement  
between A.O. Smith Water Products Company (the  
warrantor) and the owner of the water heater.  
5.5 Range of the guarantee  
All replacement water heaters supplied under the terms  
of this warranty will be supplied ex stock on an F.O.B.  
basis. A.O. Smith accepts no responsability for carriage,  
labour or other installation costs.  
5.1 Guarantee in general  
If within one year of the original installation date of the  
water heater any part or component other than the tank  
shall prove upon examination by the warrantor or  
authorised agent to be defective in material or work-  
manship, the warrantor will exchange such part or  
component.  
5.6 Claims  
Any claim under this warranty should be initiated with the  
dealer who originally sold the water heater or with any  
other dealer or stockist of the warrantors products.  
5.2 Guarantee of the tank  
If within 3 years of the original installation date, the tank  
fails due to rust or corrosion from the water side, the  
warrantor will supply a complete new water heater of  
equivalent size and duty (excluding delivery and  
installation charges). On the replacement water heater a  
guarantee will be granted sufficient to cover the  
unexpired portion of the original 3 year guarantee of the  
originally installed water heater.  
5.7 No other guarantee or warranty either  
expressed or implied is made on  
behalf of A.O. Smith Water Products  
Company.  
With respect to the water heater in question further A.O.  
Smith does not guarantee this water heater as suitable  
for purpose except within the terms of warranty detailed  
above.  
5.3 Conditions for installation and use  
The guarantee applies to the water heater only while it  
remains in its orignial location, and is installed in  
accordance with local plumbing and building  
regulations and all relevant Codes of Practice.  
A.O. Smith Water Products Company will not be liable by  
virtue of this guarantee or otherwise for damage to any  
persons or property when arising out of contracts or tort.  
The terms of this guarantee do not effect your statutory  
rights under United Kingdom Consumer Legislation.  
The water heater should also have been used only:  
a) for potable water free to circulate at all times and  
with the tank free of damaging scale deposits;  
b) at temperatures not exceeding the maximum setting  
of its thermostat and ECO (Energy Cut Off device);  
c) at water pressures and/or energy inputs which do  
not exceed those stated on the rating plate of the  
water heater;  
This guarantee applies to the following models:  
BFM 30  
BFM 50  
BFM 80  
d) in a non corrosive atmosphere or area;  
e) with an approved temperature and pressure relief  
valve of adequate capacity not exceeding the  
working pressure rating shown on the water heater,  
and installed in conformity with A.O. Smith Water  
Products Companies installation instructions;  
f) when anode(s) have been inspected and renewed,  
if they are worn or erroded by 50% of more at any  
point of their length.  
5.4 Exclusions  
The guarantee will be null and void:  
a) if the water heater has been damaged by an  
external cause;  
b) in case of misuse, neglect (including frost damage)  
or incorrect use of the water heater;  
c) in case of unauthorised alteration, modification or  
repair;  
d) in case of ingress into the water heater of  
chemicals, pollutants or contaminants;  
e) if the hardness of the incoming water is, or has  
been, softened below 106 ppm CaCO3 ;  
f) if the water heater is effected by corrosive vapours  
such as those found in hairdressers, dry cleaners  
31  
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0305 664 R0  
32  
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