A.O. Smith aosbath D25A2 User manual

User Guide
Hot Water Dispenser, HWT3

1. IMPORTANT
Please read this manual carefully before using the product and store it for future reference.
If the user installs the hot water dispenser by themselves or does it by using the self-prepared installation
materials, AOS Bath will not be liable for any adverse effects on the normal operation and service performance of
the system.
The maintenance of this machine requires the use of approved parts and the problems caused by the use of
unauthorized parts (degradation of performance or property damage) are not covered by the manufacturer's
limited warranty. If any components require a change, consumers should contact the local authorised dealer.
This appliance is not intended for use by persons (including children) with reduced physical, sensory or mental
capabilities, or lack of experience and knowledge.
Warning
: Failure to follow these instructions may lead to risk of fire and could cause property damage and or
personal injury or death
The hot water tank should be installed under-
sink, below the faucet. Do not place the tank on
the countertop or mount it on a wall. The
recommended
height distance between the
tank and faucet is 60-80cm
.
Maintain a safe distance from the faucet
exhaust and water outlet to prevent
scalding.
Do not disassemble or modify this system.
Do not expose the system to corrosive
substances.
Disconnect the system from power source
during installation and troubleshooting. Do
not touch power plug with wet hands.
Do not use a power supply that exceeds the
specifications of the machine. Ensure the
power cord and socket are in good
condition.
If any abnormality occurs, stop operation of
the system immediately.
Do not cover the appliance with
a cloth or cover the faucet
exhaust hole.
The system must be paired with
a compatible A. O. Smith RO
Water Purifier.
The tank should not be exposed
to water.
Do not place the machine close
to a fire source.
The system must be connected
to a socket with a reliable
grounding.
Use an independent use a
power socket with a minimum
rated current of 10A. Ensure all
connections are secure.

Examples of abnormal conditions
The power plug and the power cord are overheating; the power cord is damaged or there is an intermittent
power supply; the tank is damaged or misshaped, parts are loose; tank emits smoke and has a burnt smell; steam
jets from the faucet for over 10 minutes; the faucet automatically discharges hot water.
Do not place system outdoors or
under direct sunlight.
Do not place system in an area of high
temperature and humidity. Do not place in
an environment below 5ºC.
2. PRODUCT INFORMATION
FEATURES
The child-friendly under sink hot water dispenser is paired with a Reverse Osmosis water purifier to ensure that
zero trace metals are present in the water while it is being boiled. The dispenser is equipped with a patented
heating system for safe and convenient under-sink storage that does not give out steam. The hot water inner
tank material is a food-grade 304 stainless steel tank and comes equipped with a self cleaning, self-refilling
function.
SPECIFICATIONS
The Company reserves the right, at its discretion
to modify these specifications at any time.
Model D25A2 Hot Water Dispenser
Rated voltage 220V~/50Hz
Rated power 950W
Hot water tank volume 2.5L
Hot water production capacity 7L/h (>90ºC)
Shock protection Tier 1
Net weight 6.3kg
Incoming water temperature 5~38ºC
Water dispensed Potable water
Health permit approval number (2018) 3201-0108
Safety standard Q/320124 AONJ 045-2018, GB4706.19-2008
For users who are particular about consuming
water left overnight, the system easily cleans and
flushes the internal tank at the touch of a button.
High density heat insulation maximizes energy
saving for a greener environment.
DIMENSIONS (measurements in mm)

3. OPERATION GUIDE
INSTRUCTIONS
1. Child Lock
The child lock only shuts off the hot water channel. Tap indicator to
unlock. After 8 seconds of inactivity, the child lock automatically activates
again.
2. Filter Life Indicator
Different colours are displayed according to the life of the individual filters.
White
: Normal
Orange
: 5% remaining life, to be replaced as soon as possible
Red
: 0% remaining life, to be replaced immediately
To replace the filters, contact AOS Bath Singapore at 6842 0090, or order a
filter at www.aosbath.com
3. Hot Water Temperature Display
Red flame indicator lights up when heating is in progress.
4. Hot Water Volume Display
indicator reflects balance hot water available
5. Replenish Mode
Unlock the system to toggle between two replenishment modes.
Hot water
button
Room temp
water button
6. Temperature Setting
Unlock the system to toggle between four temperature modes.
Refill When Empty
When hot water is drained, tank refills automatically.
Smart Refill
When half the tank is drained, tank refills automatically.
Note
: At the point of being refilled, water will be heated to boiling point.
The system houses a smart boiling point adaptor that operates in
accordance with the altitude of the installation area. If the boiling point of
the installation area is lower than the set temperature, the system
automatically adjusts the thermostat 2ºC below the local boiling point. For
example, if the local boiling point is 95ºC and the user selects a 98ºC
temperature setting, the system will only heat to 93ºC.
Maintain at 98ºC Maintain at 90ºC Maintain at 60ºC Room Temp.

7. Tank Flush
Unlock the system to access this feature. Next, press and hold the key for 3 seconds. The
faucet will discharge hot water and drain the tank. To cancel or pause, touch the key again to
stop.
Caution: Water discharged from the faucet is hot.
INITIAL SETUP
If system is reinstalled in an area of significant altitude difference, please repeat the initial setup steps to allow for
recalibration.
2. Reset to factory settings
1. Power on Connect the power
supply and reset to
factory settings within
10 minutes of powering
up the system.
3. Complete setup
A buzzer will sound to signal an effective reset to factory settings.
Note: If you do not hear the buzzer, the system has not been reset. Repeat the steps again.
Press or raise the hot water
button (red) and at the same
time, press the room
temperature water button
(blue) 3 times.
DISPENSING WATER
1. To dispense hot water, the system must be unlocked.
The lock indicator will flash to prompt user for an unlock if the hot water button is activated without
unlocking.
2. The hot water button is red and the room temperature water button is blue.
3. Press and
hold the button
to to dispense
water and
release to stop
the flow.
4. For continuous
dispensing, lift the
button up. Return
button to original
position to stop the
flow.
Press and
hold
Lift

DISPENSER PRECAUTIONS
1. Water can only be dispensed continually for a maximum of 10 minutes.
2. Operating two buttons at the same time will stop the flow of water. To resume, return both buttons to their
original position and try again.
3. When water has just begun to boil in the tank or when water temperature is high, air bubbles may enter the
hot water pump, resulting in poor water flow. Please allow a few seconds for the water to settle and try
again.
4. When boiling has only just begun or if system has been inactive for a long period of time, the first glass of
dispensed water may not be as hot.
5. In the process of boiling, the cover of the tank and the body of the heater may feel warm to touch. This is
normal.
6. If the system is newly installed or has not been used for a long time, users are recommended to drain the hot
water twice before consumption.
FAUCET PRECAUTIONS
1. After 10 minutes of inactivity, the system enters sleep mode and the panel will only display the logo and child
lock indicator. Touch any key on the panel to exit sleep mode.
2. If the heat function of the system is deactivated, sleep mode will only display the logo, child lock indicator
and the filter life indicator.
THE WATER TANK
Power button
Heating should begin the instant the system is powered on. Press and hold the power button for 3
seconds to power the system on or off. You should hear a beep each time the button is activated.
Precautions
1. To prevent freezing in an extremely cold environment, the system will automatically power on should the
water temperature fall below 5ºC.
2. If the system has been powered on and is maintaining a fixed temperature for over 3 days with no usage, the
heat function will go off. Pressing any key on the system will reactivate it.
FAULT CODES
Code Possible reason Code Possible reason
F8 Dry heating E1 Water temperature
sensor fault
C4 Overheating E6 Steam temperature
sensor fault
C2 Level sensor data
incorrect C1 Level sensor failure

4. INSTALLATION GUIDE
The system must be installed by an authorized personnel from AOS Bath as the system can only be activated with
unique activation codes from the manufacturer.
Note: The hot water tank is specifically designed to be an under-sink tank and may not be installed on the
countertop or mounted on a wall. The recommended height distance between the tank and faucet is 60-80cm.
Failure to comply with proper installation requirements may result in a malfunction.
PREPARATION BEFORE INSTALLATION
1. Set aside a location for the hot water tank and faucet dispenser. The dispenser should be mounted on the
countertop and the tank should be below it, under the sink.
2. Check that you have the necessary tools on hand for the installation: An electric drill, a pair of needle-nosed
pliers, a countertop drill, a 3mm drill bit, an adjustable wrench (>37.5m opening), a cross screwdriver and a
slotted screwdriver.
INSTALLING THE FAUCET
If countertop surface is very thin, it follows that the faucet may be slightly unstable after installation. This is still
acceptable for operation.
Hot water
button
Room temp. water button
Spout
Touch screen display
Aerator
Body
Base cap
O-ring Nut
Exhaust
Room temp. water pipe
Mounting base
Lock bolt, base
Hot water pipe
Lock bolt, flat
Base reinforcement
Data cable
1. Drilling
Drill a hole of 26-32mm in
diameter to begin the
installation.

4. Tighten the base
Tighten the locking bolts at the base
with an M7 allen key (provided).
Allen key
5. Install the faucet
Cut two flexible pipes
of the right length and
insert them through a
holder at the faucet’s
main body. Insertion
points should
correspond with the
specially designed
connection holes of
the mounting base.
Body
Tip
: Before insertion, draw a line 16mm away from the end of the water pipe. After the water pipe is inserted,
the marking line should not be visible.
Align the
faucet with the
mounting base
and use a
wrench to fix
the nut firmly
on to the
mounting base.
6. Tighten the nut
Nut
Wrench
7. Complete installation
Place base cap
above the nut to
complete the
installation.
Base cap
Note: When cleaning the surface of the faucet, use a soft sponge. Avoid metal sponges to prevent scratches
and damage. A faucet damaged in this manner will not be covered under the warranty.
2. Install base reinforcement 3. Insert the base
Insert the
mounting base
into the hole
from above.
Tear off the double-sided tape on the base
of the base reinforcement and paste it at
the inline at the base of the hole.
Mounting
base
Lock bolt, base

WIRING DIAGRAM
PRECAUTIONS
1. Use a dedicated power socket.
2. Before connecting the new water purifier to the hot water tank, ensure the water purifier has been flushed
correctly.
Exhaust
Water purifier
data cable
Purified water
feed tube
Faucet
data
cable
Room
temp.
water
outlet
Hot
water
outlet
Power cable

5. SYSTEM DIAGRAM
EXPLODED VIEW DRAWING
Top cover
Steam sensor
Check valve
Heater cover & steam condenser
Right panel
Water level
sensors
Thermal
insulation
Bottom cover
Power supply board
LED display
Power button
Solenoid valve
Left panel
Heating indicator
Heating element
Fuse
Water pump
Water temp. sensor
Thermal cut out

ELECTRICAL DIAGRAM
Power cable
220V/50Hz
Room
temp.
outlet
valve
Hot water
tank inlet
valve
Tank
M
Faucet
dispenser
Main control board
Steam sensor
Temperature sensor
Printed
circuit board
Fuse
Primary heating
element
Water
Purifier
Heating element
Thermostat
Water
level sensors
Filter replacement
data cable
SYSTEM
Solenoid valve
Purified water
direct from filter
Room temp.
water outlet valve
Hot water tank
inlet valve
Exhaust and inlet
Tank cover and steam condenser
Tank
Heating element
Water
level
sensors
Water pump
Faucet
dispenser

6. TROUBLESHOOTING
Fault Possible Causes Corrective Action
No or low hot water
flow
Hot water or exhaust pipes are blocked Check for blockages on both pipes
Child lock is on Unlock the child lock
No hot water in tank Wait for water to refill and try again
Air bubbles in dispenser unit Try again after 10 seconds
Faucet dispenser is faulty Replace faucet dispenser
No room temperature
water
There is no water in the water purifier
tank
Check water purifier for any alerts
pertaining to water shortage
Water purifier is leaking Check water purifier for any alerts
pertaining to water leaks
Water purifier connection is
disconnected
Reconnect water purifier and faucet
dispenser
Faucet dispenser is faulty Replace faucet dispenser
Circuit board failure Call AOS Bath service hotline [phone]
System is not heating
up
System is powered off Power on from button on tank body
System is in room temperature mode Switch the mode on the faucet
Main control board failure Call AOS Bath service hotline [phone]
Top of the tank
produces a lot of
steam
Thermostat failure Power off system immediately and call
AOS Bath service hotline [phone]
Code Qty Code Qty
Tank 1Instruction manual 1
Faucet dispenser 1Faucet installation accessories 1
4-core data cable 1Tank installation accessories 1
5-core data cable 1Flexible pipes NA
IN THE BOX
TROUBLESHOOTING