A.O. Smith STE - 400 Troubleshooting guide

0311 370 / 03-2014 Innovation has a name.
Commercial Electric Storage
Water Heater
STE - 400/500/600/750/1000
STE
Installation, User and Service
Manual
Changes Reserved

A.O. Smith Europa, De Run 5305, 5503 LW Veldhoven, The Netherlands
[phone]
your installer

Installation, User and Service Manual
3
Read this manual
carefully
Trademarks
Liability
More information
Warning
Read this manual carefully before starting the electric storage water heater. Failure to read
the manual and to follow the printed instructions may lead to personal injury and damage to
the electric storage water heater.
Copyright © 2014 A.O. Smith Water Products Company B.V.
All rights reserved.
Nothing from this publication may be copied, reproduced and/or published by means of
printing, photocopying or by whatsever means, without the prior written approval of
A.O. Smith Water Products Company.
A.O. Smith Water Products Company reserves the right to modify specifications stated in
this manual.
Any brand names mentioned in this manual are registered trademarks of their respective
owners.
A.O. Smith Water Products Company accepts no liability for claims from third parties arising
from unauthorised use, use other than that stated in this manual, and use other than in
accordance with the General Conditions registered at the Chamber of Commerce.
Refer further to the General Conditions. These are available on request, free of 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 if you would inform us. This helps us to further improve our documentation.
If you have any comments or queries concerning specific aspects related to the water
heater, then please do not hesitate to contact:
A.O. Smith Water Products Company B.V.:
PO Box 70
5500 AB Veldhoven
The Netherlands
Telephone: 008008 - AOSMITH
008008 - 267 64 84
General: [phone]
Fax: [phone]
E-mail: [email protected]
Website: -
In the event of problems with your gas, electricity or water supply connections, please
contact the supplier/installation engineer of your installation.

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Table of contents
1
1.1
1.2
1.3
1.4
1.5
1.6
2
2.1
2.2
2.3
3
3.1
3.2
4
4.1
4.2
5
5.1
5.2
5.3
5.4
5.5
5.6
5.7
Technical specifications ....................................................................................... 7
Floor load ............................................................................................................................. 7
Water composition ............................................................................................................... 7
Working clearance ............................................................................................................... 7
General specifications .......................................................................................................... 7
Electrical specifications ........................................................................................................ 8
Dimensions .......................................................................................................................... 8
Installation ............................................................................................................ 11
Installation diagram ............................................................................................................ 11
Water connections ............................................................................................................. 11
Electrical connections ........................................................................................................ 12
Maintenance ......................................................................................................... 15
Preparation for maintenance .............................................................................................. 15
Water-side maintenance .................................................................................................... 15
Errors .................................................................................................................... 17
Introduction ........................................................................................................................ 17
Troubleshooting table ......................................................................................................... 18
Warranty ............................................................................................................... 21
General warranty ................................................................................................................ 21
Tank warranty .................................................................................................................... 21
Conditions for installation and use ..................................................................................... 21
Exclusions .......................................................................................................................... 22
Scope of warranty .............................................................................................................. 22
Claims ................................................................................................................................ 22
Obligations of A.O. Smith ................................................................................................... 22

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1 Technical specifications
1.1 Floor load
1.2 Water composition
1.3 Working clearance
Take the storage water heaters weight in account for the maximum floor load; refer to the
table (1.4 "General specifications").
The storage water is intended for heating drinking water. The drinking water must comply
with the regulations governing drinking water for human consumption. The table gives an
overview of the specifications.
Water specifications
Water composition
Hardness
(alkaline earth ions)
> 1,00 mmol/l:
German hardness > 5,6 °dH
French hardness > 10,0 °fH
English hardness > 7,0 °eH
> 100 mg/l CaCO3
> 100 ppm CaCO3
Conductivity
> 125 μS/cm
Acidity (pH value)
7,0 < pH value < 9,5
Note
If the water specifications deviate from those stated in the table, then the tank protection
cannot be guaranteed (4 "Warranty").
For access to the storage water heaters, it is recommended that the following clearances
are observed:
around the anode connection/top of the water heater: 100 cm.
around the water heater: 50 cm.
1.4 General
specifications
General Specifications - water heater
Unit
STE 400
STE 500
STE 600
STE 750
STE 1000
Contents
litres
405
499
678
763
1055
Empty weight
kg
99
131
179
201
262
Maximum floor load
kg
504
630
957
964
1317
Maximum operating pressure
kPa (bar)
1000 (10)
1000 (10)
1000 (10)
1000 (10)
1000 (10)
Maximum water temperature
ºC
95
95
95
95
95
Anodes
-
1
1
1
1
1

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1.5 General
specifications
Electrical Specifications - flange element
Unit
2.0 kW
2.5 kW
3.3 kW
6.0 kW
7.5 KW
Supply voltage (-15%, +10% VAC)
Volt
230
230
230
400
400
Number of phases
-
1
1
1
3
3
Current (max. amount per phases)
A
8.7
10.9
14.4
5
6.3
Mains frequency (±1 Hz)
Hz
50
50
50
50
50
IP class
-
IP-5X
IP-5X
IP-5X
IP-5X
IP-5X
Maximum operating pressure
kPa (bar)
600 (6)
600 (6)
600 (6)
600 (6)
600 (6)
Max. Setpoint Control Thermostat
°C
85
85
85
85
85
Overheat Thermostat
°C
95
95
95
95
95
Electrical Specifications - screw-in element
Unit
2.0 kW
2.5 kW
3.0 kW
4.5 kW
6.0 kW
7.5 KW
Supply voltage (-15%, +10% VAC)
Volt
230
230
400
400
400
400
Number of phases
-
1
1
3
3
3
3
Current (max. amount per phases)
A
8.7
10.9
2.5
3.8
5
6.3
Mains frequency (±1 Hz)
Hz
50
50
50
50
50
50
IP class
-
IP-5X
IP-5X
IP-5X
IP-5X
IP-5X
IP-5X
Maximum operating pressure
kPa (bar)
600 (6)
600 (6)
600 (6)
600 (6)
600 (6)
600 (6)
Max. Setpoint Control Thermostat
°C
85
85
85
85
85
85
Overheat Thermostat
°C
95
95
95
95
95
95
1.6 Dimensions
Unit
STE 400
STE 500
STE 600
STE 750
STE 1000
A
Total height
mm
1705
2040
1835
2030
2000
D
Diameter tank (with insulation)
mm
720
720
910
910
1060
Diameter tank (without insulation)
mm
606
606
796
796
946
M
Height cold water inlet
mm
70
70
85
85
95
N
Height warm water outlet
mm
1650
1990
1797
1992
1962
O
Diameter inspection opening
mm
115
115
180
180
180
P
Height inspection opening
mm
410
410
493
493
530
R
Height connection
mm
270
270
315
315
360
S
Height temp. sensor connection
mm
348
348
400
400
445
T
Height connection
mm
425
425
485
485
530
U
Height recirculation connection
mm
510
510
650
650
700
V
Height connection
mm
826
995
1040
1080
1100
W
Height connection
mm
1094
1348
1255
1374
1351
X
Height T&P connection
mm
1362
1700
1466
1662
1592
1
Cold water inlet
-
R 2
R 2
R 2½
R 2½
R 2½
2
Warm water outlet
-
R 2
R 2
R 2½
R 2½
R 2½

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Unit
STE 400
STE 500
STE 600
STE 750
STE 1000
7
Connection
-
Rp ¾
Rp ¾
Rp ¾
Rp ¾
Rp ¾
8
Anode connection
-
Rp 1¼
Rp 1¼
Rp 1¼
Rp 1¼
Rp 1¼
11
Connection
-
Rp 2
Rp 2
Rp 2
Rp 2
Rp 2
12
Connection
-
Rp 2
Rp 2
Rp 2
Rp 2
Rp 2
13
Connection temp. sensor
-
Rp ¼
Rp ¼
Rp ¼
Rp ¼
Rp ¼
14
T&P connection
-
Rp 2
Rp 2
Rp 2
Rp 2
Rp 2
IMD-0526 R0.0
D
M
R
S
V
W
X
N
A
T
U
P
1
12
13
11
7
7
7
14
O
8
2

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2 Installation
2.1 Installation diagram This figure shows the installation diagram. This diagram is referred to in the sections
describing the actual connection procedure.
Installation diagram
Legend
2. inlet security group
3. T&P-valve (mandatory)
4. stop valve (recommended)
5. non-return valve (mandatory)
6. circulation pump (optional)
A. cold water supply
B. hot water supply
C. circulation pipe
F. inlet heat exchanger
G. outlet heat exchanger
IMD-0545 R0.0
2.2 Water connections
2.2.1
Warning
The installation should be carried out by a competent person, in compliance with general
and locally applicable regulations.
Cold water side
See (A) in the installation diagram (2.1 "Installation diagram").
1. The maximum working pressure of the storage water heater is 10 bar. Because the
pressure in the water pipe at times can exceed 10 bar, you must fit an approved
pressure-reducing valve.
2. Fit a approved inlet security group (2) according local guidelines.

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2.2.2
2.2.3
2.3 Electrical connections
2.3.1
2.3.2
Hot Water side
See (B) in the installation diagram (2.1 "Installation diagram").
Note
Insulating long hot water pipes prevents unnecessary energy loss.
1. Optional: fit a temperature gauge so you can check the temperature of the tap water.
2. Fit the T&P valve (3).
3. Fit a stop valve in the hot water outlet pipe for servicing.
Circulation pipe
See (C) in the installation diagram (2.1 "Installation diagram").
If an immediate flow of hot water is required at draw-off points, a circulation pump can be
installed. This improves comfort, and reduces water wastage.
1. Fit a circulation pump (6) of the correct capacity for the length and resistance of the
circulation system.
2. Fit a non-return valve (5) after the circulation pump to guarantee the direction of
circulation.
3. Fit two stop valves for servicing (4).
4. Connect the circulation pipe according to the installation diagram (2.1 "Installation
diagram").
Warning
The installation should be carried out by a competent person, in compliance with general
and locally applicable regulations.
Introduction
1. Remove, depending on the type of element, one (flange element) or two screws
(screw-in element) in order to remove the plastic cover from the element.
2. Carefully remove the plastic cover from the heating element.
3. The electrical section can now be seen.
Electrical Element - flange
1. Mount the element in the inspection opening of the tank.
2. Feed the power cable through the grommet.
Warning
Not all flange-elements have the same supply voltage, see below.
Supply voltage flange-elements
Element
2.0 kW
2.5 kW
3.3 kW
6.0 kW
7.5 KW
Supply Voltage (+10%,-15%)
230 VAC
230 VAC
230 VAC
400 VAC
400 VAC
Phase
1
1
1
3
3

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2.3.3
Connecting an element of 230 VAC
3. Connect the neutral (N), of the power cable, to the N-terminal on the thermostat;
4. Connect the live (L), of the power cable, to the L-terminal on the thermostat;
5. Connect the earth ( ), of the power cable, to the earth-terminal, in the element.
Connecting an element of 400 VAC
3. Connect the first live (L), of the power cable, to the L1-terminal on the thermostat;
4. Connect the second live (L), of the power cable, to the L2-terminal on the thermostat;
5. Connect the third live (L), of the power cable, to the L3-terminal on the thermostat;
6. Connect the earth ( ), of the power cable, to the earth-terminal, in the element.
Electrical Element - screw-in
1. Remove the cover and gasket from the inspection opening;
2. Mount the supplied flange and gasket in the inspection opening. For elements that
need to be mounted in an STE 600, 750 or 1000 an additional reducing flange needs
to be mounted first before the flange with screw-connection can be mounted.
3. Mount the element in the flange.
4. Feed the selected (power) cable through the grommet.
Warning
Not all screw-in elements have the same supply voltage, see below.
Supply voltage flange-elements
Element
2.0 kW
2.5 kW
3.0 kW
4.5 kW
6.0 kW
7.5 KW
Supply Voltage (+10%,-15%)
230 VAC
230 VAC
400 VAC
400 VAC
400 VAC
400 VAC
Phase
1
1
3
3
3
3
L1
L2
L3
N
L

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Connecting an element of 230 VAC
5. Connect the neutral (N), of the power cable, to the N-terminal on the thermostat;
6. Connect the live (L), of the power cable, to the L-terminal on the thermostat;
7. Connect the earth ( ), of the power cable, to the earth-terminal, in the element.
Picture not available
Picture not available
Connecting an element of 400 VAC
5. Connect the first live (L), of the power cable, to the L1-terminal on the thermostat;
6. Connect the second live (L), of the power cable, to the L2-terminal on the thermostat;
7. Connect the third live (L), of the power cable, to the L3-terminal on the thermostat;
8. Connect the earth ( ), of the power cable, to the earth-terminal, in the element.
L1
L3
L2

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3 Maintenance
3.1 Preparation for
maintenance
3.2 Water-side
maintenance
3.2.1
3.2.1
Warning
Maintenance may only be carried out by a competent person.
At each service, the storage water heater undergoes maintenance on water side. The
maintenance must be carried out in the following order.
1. Preparation for maintenance
2. Water-side maintenance
3. Finalising maintenance
Note
Before ordering spare parts, it is important to write down the installation type, storage
water heater model and the full serial number of the storage water heater. These details
can be found on the rating plate. Only by ordering with this information can you be sure
receiving correct spare parts.
The preparation for maintenance consists of testing and checking if all components are
still working properly by completing the following steps:
1. Test the operation of the overflow valve of the protected cold supply setup. The water
should discharge out.
2. Check the drainage pipes from the discharge points of all valves and remove any
scale deposits that may be present.
3. Drain the storage water heater.
Water-side maintenance consists of descaling and cleaning the tank, cleaning the
elements and checking the anodes.
Cleaning the elements
Scale and lime build-up prevent effective conduction of the heat to the water. Periodic
cleaning and descaling the tank prevents build-up of these deposits. This increases the
service life of the element and also improves the heating process.
Descaling and cleaning the tank
Scale and lime build-up prevent effective conduction of the heat to the water. Periodic
cleaning and descaling prevents build-up of these deposits. This increases the service
life of the storage water heater and also improves the heating process.
Take the rate of scale formation into account when deciding on the service interval.
Scale formation depends on the local water composition, the water consumption and the
water temperature setting. A water temperature setting of maximum 60°C is
recommended for the prevention of excessive scale build-up.
To guarantee a good, watertight seal around the cleaning opening, replace the gasket,
washers, bolts and, if necessary, the lid with new parts before reassembly. Spare parts
are obtainable from the supplier/manufacturer.
To simplify descaling and cleaning of the tank, the storage water heater is equipped with
a cleaning opening.

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3.1.2
3.1.3
Work order:
1. Undo bolts from the cover.
2. Remove cover and the gasket.
3. Inspect the tank and remove the loose scale deposits and contamination.
4. If the scale cannot be removed by hand, descale the storage water heater with a
descaling agent. Contact the supplier/manufacturer for advice on what descaling
agent to use.
5. Close the cleaning opening. To avoid damage to the tank tighten the bolts, that
fasten the lid, with a torque no greater than 50 Nm. Use suitable tools for this.
Checking anode
The anode ensures the protection of the tank by sacrificing himself. Insufficient anode
material may lead to poor protection and, hence, leakage of the tank.
Storage water heater
1. Loose the anode.
2. Check the diameter of the anode in different places. The diameter must be at least
60% of the original 1” diameter.
3. If the diameter is less than the minimum, the anode must be replaced. Please contact
the supplier/manufacturer to order new anodes.
4. Mount the (new) anodes.
Importent
Anode must make electric connection in the tank. Make sure that the thread is not
isolated from the tank.
Electrical heating element
1. Remove the element from the tank.
2. Check the diameter of the anode in different places. The diameter must be at least
60% of the original 1” diameter.
3. If the diameter is less than the minimum, the anode must be replaced. Please contact
the supplier/manufacturer to order new anodes.
4. Mount the (new) anodes.
Checking heating element
The electrical heating element should be free of scale and lime build-up. The build-up of
scale and lime prevent proper function of the element. The build-up of scale and lime
may lead up to failure of the element.
Note
The first check of the elements must be done after 3 months.

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4 Errors
4.1 Introduction
This chapter deals with the following problems with the water heater:
Water leakage
No hot water
Insufficient hot water

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4.2 Troubleshooting table
Symptom
Cause
Precautions
Comment
Water leakage
Leakage from a water connection (threaded).
Tighten the threaded connection.
If the leak persists, consult you
installation engineering.
Leakage from another nearby water heater or pipe
segment.
Trace the leak.
Leakage from the water heater tank.
Consult you supplier, installer and/or manufacturer.
Condense.
Stop draining of (to much) hot water until the water
reached the set temperature.
Insufficient or no hot
water
No supply voltage.
1. Check whether the electrical element is ON.
2. Check the main power supply.
3. Check whether there is power on the element.
If the error cannot be resolved or is
persistent, contact your installation
engineer.
The element is switched off.
1. Check whether the element is ON.
2. Check whether there is power on the connector block of
the element.
3. Check whether the element(s) is defective.
Safety thermostat has cut out.
1. The safety thermostat cut out correctly:
- Reset the element.
- Check whether the control thermostat is working.
- Check whether the circulation pump is working.
2. The safety thermostat has cut out without apparent
reason:
- Check whether the thermostat is defective.
- Check whether the sensor of the thermostat is
defective.
Water temperature setting is too low.
Set the control thermostat to a higher value.
Element defect.
Check the resistance of the element(s). At roomtempe-
rature the resistance of a element must be between 32 and
33 Ohm. If the resistance value is significantly different
(due to closed or open circuit) this indicates a fault element
and should be replaced.
To replace the necessary parts, you
must contact your installation
engineer.

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Symptom
Cause
Precautions
Comment
Element(s) switched off.
1. Check whether the element is ON.
If the error has not been rectified and
no other cause can be found, isolate
the water heater and alert you
installation engineer.
Hot water supply is used up.
1. Reduce hot water consumption and give the water
heater time to heat up.
2. If this error persists, check whether the safety
thermostat is switching. If this is the case, check if the
circulation pump is working properly.

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