A.O. Smith CEWH-A1 Series Service manual

2012-12-5
A.O.Smith reserves the right to make product changes or improvements at any time without notice. 407092-012Rev.03
A.O.SMITH WATER HEATER CO.,LTD

CEWH-A1
INSTALLATION & INSTRUCTION MANUAL
A.O.SMITH WATER HEATER CO.,LTD
Cylinder ElectricWall-Hung Water Heater

Congratulations on your purchase of a new, high quality wall -
hung water heater from A.O.Smith. Your heater is equipped
with technology and features that only a company
with over sixty years of experience can deliver. With the proper
care, your heater will deliver comfortable
hot water for years to come.
We are concerned about your safety
and ask you to read this manual thoroughly and
pay close attention to all
of the warning and information
contained inside. Be sure to keep these instructions for
future reference.
Thank you for buying an A.O.Smith brand water heater.
CEWH-A1 Cylinder Electric Wall-Hung Water HeaterCEWH-A1 Cylinder Electric Wall-Hung Water Heater

Table of Contents
1
2
2
3
3
3
3
3
3
4
4
4
4
7
7
7
7
7
7
8
8
8
9
9
General Safety Information
Physical Characteristics
Specifications Chart
Safety Features
High Temperature Limit Control (High Limit)
Safety Valve
Product Features
Thermostat
Enamel Coating Tank
High-efficient Energy-saving Insulation Layer
Anode Rod Protection
Installation Instruction
Installation
Water Connection
Power Connection
Filling
Operation Instruction
Temperature Setting
Operating
Note
Repair and Maintenance
Maintenance
Troubleshooting
Wiring Diagram
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CEWH-A1 Cylinder Electric Wall-Hung Water HeaterCEWH-A1 Cylinder Electric Wall-Hung Water Heater

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Attention: If not abide by the content of this manual strictly, fire may be caused and leads to
property damage, personal injuries or death.
Warning:Power socket cannot be used unless it is well grounded. Do not use ungrounded water
heater.
General Safety Information
We strongly suggest that you read this manual thoroughly before installation and use of this water heater.
Be sure to keep these instructions for future reference.
A. O. Smith Company will not be liable for any damage resulting from incorrect installation of this
water heater. Only professionals recognized by A. O. Smith are allowed to install this water heater
for you.
Be sure to shut off the power before any repair and maintenance for this water heater. Non-
professionals are not allowed to adjust or repair this water heater.
Hot water may cause serious scalding injury. Hot water must be mixed with cold water before
shower or washing.
The water heater system may produce steam or extremely hot water if burned without water inside
the tank. Any parts dipped in the water needs to be examined or repaired by qualified professionals
before next use.
For water heaters equipped with power cord, if the power cord is damaged, only customer service
personnel of water heater manufacturer or similar professionals are allowed to replace it. All key
parts of this water heater are insulated or have heat-insulated coating, users may rest assured in
using it.
For the purpose of safe use, it is prohibited to alternate the installation position of the pressure-relief
safety valve without permission or block its outlet.
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Standard:GB4706.1 GB4706.12
Figure I - Physical Characteristics
CEWH-A1 Cylinder Electric Wall-Hung Water HeaterCEWH-A1 Cylinder Electric Wall-Hung Water Heater
Model CEWH-40A1 CEWH-50A1 CEWH-60A1 CEWH-80A1 CEWH-100A1
L(mm) 710 830 692 860 1025
S(mm) 200 200 250 250 250
D(mm) φ360 φ360 φ463 φ463 φ463
L1(mm) 265
Model
CEWH-40A1
CEWH-50A1
CEWH-60A1
CEWH-80A1
CEWH-100A1
40
50
60
80
100
220V~ 50/60Hz
220V~ 50/60Hz
220V~ 50/60Hz
220V~ 50/60Hz
220V~ 50/60Hz
2500
2500
2500
2500
2500
9.1
9.1
9.1
9.1
9.1
（30~75）±5
（30~75）±5
（30~75）±5
（30~75）±5
（30~75）±5
0.8
0.8
0.8
0.8
0.8
19
21
25
31
35
Capacity
（L）
Current
（A）
Temp.Range
（℃）
Rated Water
Pressure
（MPa）
Net Weight
（kg）
Voltage（V）/
Frequency（Hz）Input（W）
330 272 365 435
Water Outlet (hot)
1/2" BSP Thread
Water Inlet (cold)
Safety Valve
Thermometer
Knob
Indicator light
D
L1
L

Product Features
Thermostat:
The liquid-expansion thermostat senses water
temperature fast, reliable and accurate. Water temperature
can be adjusted by the external knob conveniently and
fast (See figure II).
Figure II
High Limit:
The high limit rapidly cuts off live line and zero line simultaneously to guarantee safety in case the
water heater happens to be faulty and water temperature exceeds the highest temperature pre-set in the
thermostat.
Safety Valve:
This appliance has a pressure relief valve (see Figure I). It must be installed in the inlet piping
(blue). It has been factory set at 0.8 MPa and is not adjustable. This valve relieves and discharges when
the actual pressure in the piping exceeds this set rate. The discharge outlet of this valve must face downward,
and the discharged water must be piped into or within 15cm above a suitable drain. Under any circumstances,
the drain line cannot be blocked, and must be open to atmosphere. Please refer to Figure VII for water
installation.
Safety Features
Enamel Coating Tank:
With the advanced anticorrosive technique, A. O. Smith Company evenly coats special silicon frit
onto the tank inner surface and fuse the frit coating to the steel at a high temperature of 870°C, forming a
durable enamel coated tank. It can endure huge impact without breaking off and completely isolate the
water inside the tank from the tank surface. It has passed the 100,000 times cycle test per UL (Underwriters'
Laboratories) standard and proved to be one of the most durable water heater tanks due to its antirust and
antiscale features.
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High-efficient Energy-saving Insulation Layer:
This extra-thick CFC-free polyurethane insulation layer keeps temperature well and reduces heat
loss maximally.
Anode Rod Protection:
This strong anode rod with stainless-core protects the tank to be durable and greatly prolongs the life
of water heater.
Warning: Hot water exceeding 50°C can produce scalding injury. Care should be taken when
the temperature is set over 50°C for the safety of your family and children in particular.
Installation Instruction
Installation:
Locate the heater near electric power socket, floor drain and point of water use. Be sure the inlet
and outlet of the heater are on the bottom and facing downward. Don't permit to install it vertically!
Warning: Be sure to install the water heater with the provided mounting brackets. The heater can be
hung up only after the mounting brackets are solidly mounted and double check. Serious damage
and harm can result if the heater falls off from the wall.
Make sure that the wall can withstand double weight of fully filled water heater.
To locate the fixing bolts, make sure that there is a clearance of no less than 300mm between the right
side of the heater and the wall in order to facilitate opening up the plastic service cover for maintenance
or resetting the high limit when necessary. In case the water heater is embedded in the ceiling, the
right side ceiling of the heater should be removable so as to remove the plastic service cover for
maintenance when necessary.
Use 10mm drill to drill 2 holes of at least 90mm depth in wall. The 2 holes should be in line horizontally.
See Figure III for distance specification.
Installation Procedure and Cautions
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Use the hex wrench and expansion bolts to mount and fix the hangers on the wall. See Figure IV for
details:
Cautions:
Figure III
Figure IV
L
The nylon expansion tube must be put through the hole of the hanger first, before inserted
into the drilled hole.
Must use the special hex wrench to drive the bolt into the nylon expansion tube. Don't
permit to use other tools. Once the bolt head pressing the hanger plate and making the
hanger unmovable by itself, stop further tightening to prevent damaging the nylon tube.
*
*
Hang up the water heater by placing the 2 square holes of mounting bracket into the hanger hooks on
the wall. Move the water heater downward to ensure that the square holes are fastened to the root of the
hanger hooks and confirm water heater is fixed steadily. See Figure V for details.
90mm
ø10
Wall
Square Hole
Figure V
CEWH-A1 Cylinder Electric Wall-Hung Water HeaterCEWH-A1 Cylinder Electric Wall-Hung Water Heater
Model
CEWH-40A1
CEWH-50A1
CEWH-60A1
CEWH-80A1
CEWH-100A1
L（mm）
260
380
260
380
380
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Caution: The provided mounting hangers can only be used on solid cement wall. Inappropriate
installation may result in heater falling off. See Figure VI for details.
Figure VI
gnorWtcerroC
Mixing Water
Floor Drain
Figure VII Water Connection
Hot Water Outlet
Safety Valve
Lever
Cold Water Inlet
Tube
Mixing Valve
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Water Connection:
Install the pressure-relief safety valve in the water inlet (blue). The direction of arrow points to the
water heater. It indicates the direction of water flow current. Connect hot water pipe to the red outlet. See
above content about safety valve for the installation of safety valve. Attention: Make sure a suitable tape
thread sealant is used for all connections to prevent leakage. Meanwhile the safety valve must not be
tightened too fast to prevent damage. In case that the supplying water pressure is close to the safety valve
rating, please install a pressure-reducing valve in inlet piping with sufficient distance away from the heater.
See Figure VII for water connection details.
Electrical Power Connection:
The power cord and plug have been equipped and connected with this water heater. Just plug it into a
corresponding socket. Attention: Please make sure the water heater and the socket are appropriately
grounded. More over, the socket must be of good quality to ensure good contact with the plug.
Filling:
After all the piping connection is done, fully open the cold water faucet and hot water faucet to fill
the water heater and drain the air out until water flows from outlet faucet, which indicates the heater is
filled. Then close the hot water faucet and check all the connections to see if there is any leak. If it leaks,
drain the heater completely, repair the leaking joint and then re-fill the heater.
Temperature Setting:
Set the water temperature by adjusting the temperature setting knob on the right side of the
water heater. The set temperature goes up when turning down the knob and the set temperature goes
down when turning upwards. Normally, it has been factory set at the highest temperature.
Operating:
After making sure the heater is filled up, turn the power on. When the indicating light is on, the
heater is being heating; if the light goes off, it means the heater has been heated to the set temperature.
Operation Instructions
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Repair and Maintenance
Declaration: Only qualified service technicians are allowed to repair and maintain this water heater.
Incorrect operation may cause serious injuries or property loss.
Warning-Electric shock: This appliance must be unplugged before being opened up or repaired.
Attention: Before calling for repair service, please use the Troubleshooting lists on the next page as
a guide to correct apparent problems.
Note:
It is normal that there is water dripping from the safety valve outlet during heating. Under normal
use, the safety valve lever should be opened periodically. If water flows, the relief valve is in good working
condition; if not, please contact local customer service for maintenance.
Maintenance:
When it is necessary to drain the water heater, close inlet valve, open outlet valve and lift the lever of
pressure-relief safety valve, then the water will flow out of the discharge pipe.
Clean water tank periodically to remove scale.
Step by step guides: 1) Shut off power. 2) Remove pressure-relief safety valve and water inlet. 3) Connect
water outlet to tap water to become water inlet; connect original water inlet to floor drain with a pipe to
become water outlet. 4) Fully open the water inlet valve to wash the tank with large water flow until the
water flowing out of the tank becomes clean. 5) Re-connect water inlet and outlet according to Figure VII
and start to use after leakage test is qualified.
Caution: Water discharged could be very hot, please take care so as not to be scalded.
CEWH-A1 Cylinder Electric Wall-Hung Water HeaterCEWH-A1 Cylinder Electric Wall-Hung Water Heater
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Troubleshooting
Problem Possible Cause Solution
Indicator light off
No hot water
1) Heater is not switched on
2) Heater is power off
3) No power in power socket on the wall
4) Control circuit or internal wiring error
1) Rotate the adjusting knob
2) Turn on the heater power
3) Check the socket
4) Contact customer service
Indicator light off
Water temperature too high
1) High-limit trip
2) Thermostat faulty
1) Contact customer service
2) Contact customer service
Indicator light on, no hot
water
Heating element(s) breakdown or internal
wiring error Contact customer service
Piping connection leaks Connectaion not sealed
Re-connect piping, must
use tape thread sealant
Cover leaks Tank or parts leak
Shut off power immediately
and contact customer service
Figure VIII Wiring Diagram
CEWH-A1 Cylinder Electric Wall-Hung Water HeaterCEWH-A1 Cylinder Electric Wall-Hung Water Heater
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L N GND
Brown Blue
Yellow
green
High limit
Blue
Brown Thermostat
White
Indicator
light
N
L
Element

A pipe V
Packing List:
i) Electric Water Heater, 1 set; ii) Instruction Manual, 1 piece; iii) Relief Valve, 1 piece; iv)
Bracket Accessory, 1 set
CEWH-A1 Cylinder Electric Wall-Hung Water HeaterCEWH-A1 Cylinder Electric Wall-Hung Water Heater
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