Dewhot 12lt User manual

12lt
Constant Temperature

Page 3 of 30 Dewhot | Gas geyser manual
Read these instructions carefully before operating the
gas geyser and familiarize yourself with the appliance
before connecting it to the gas cylinder. Keep these
instructions for future reference.
This appliance is manufactured to operate on LPG
only. Do not tamper or modify the appliance.
If you smell gas
1. Turn o the gas supply at the bottle
2. Extinguish all naked ames
3. Do not operate any electrical
appliances
4. Ventilate the area
5. Check for leaks as described in this
manual
6. If gas smell persists, contact your
dealer or gas supplier immediately
Burn-back
In the event of a burn-back, where the
ame burns back to the jet, immediately
turn the gas supply o at the gas cylinder.
After ensuring the ame is extinguished,
wait for I minute and then reignite the
appliance as per normal. Should the
appliance burn back again, close the gas
cylinder and call a registered LPG installer.
Do not use the appliance again until the
installer has conrmed that it is safe to
do so.
Gas-pressure regulator
This appliance requires an operating
pressure of 2,8 kpa. Only install a LPG
regulator that complies with the
SANS 1237 requirements.
Guarantee
After installation, please register your
product on the Dewhot website (www.
gasgeysers.co.za/product-registration)
You will need your invoice and Certicate
of Compliance (COC) to complete the
registration.
Important

Page 4 of 30 Dewhot | Gas geyser manual
Burner
Parts Diagram LCD screen
Controller
box
LCD
screen
Pilot
assembly
Pilot
jet
Gas
valve
Battery
Box
Pilot
tube
Burner
Washer
Jet Bar
Test Point

Page 5 of 30
Dewhot | Gas geyser manual
Dewhot | Gas geyser manual
Outlet Temp sensor
850C Temp sensor
1100C Temp sensor
Cover
Chimney box
Inlet water valve
Water ow sensor
Inlet Temperature sensor
Radiator

Page 6 of 30 Dewhot | Gas geyser manual
Technical parameters
Description Constant temperature
Model no NDCT12DH
Model Type B
Gas type LPG
Max gas pressure 2,8kpa
Rated input 24kw
Water pressure 20-500 kPa
Maximum Water Flow 12L/min
Max Gas Consumption 1.44kg/h
Unit Size 715x 400x 240mm
GW 11.2kg NW 9.6kg

Page 7 of 30
Dewhot | Gas geyser manual
Dewhot | Gas geyser manual
CONSTANT HOT WATER SUPPLY
The water heater will achieve and maintain
the water temperature set on the digital
display automatically, irrespective of
changing water ow and temperatures.
TEMPERATURE MEMORY
FUNCTION
The CPU of the controller will remember
the temperature settings from the
previous use, improving the reaction
time upon start up.
EASY OPERATION
Simplicity of adjusting the temperature
of the hot water by 1°C increments at the
touch of a button.
PILOT IGNITION
The pilot burner will automatically ignite
rst, then the main burner. The pilot will
then go o avoiding excessive gas usage.
FLUE BLOCKAGE PROTECTION
The geyser turns o automatically if the
ue is blocked. Whether it is installed
indoors or outdoors the geyser should be
tted with a ue to avoid unneccesary
cutting o.
CAN BE USED TO BACK UP
SOLAR GEYSERS
Use this gas geyser in conjuction with
our solar to gas valve to boost your solar
water temperature in the winter months or
colder, cloudier summer days.
FLAME OUT SENSOR
This is designed to automatically cut o
the gas supply should the ame/ burner
unexpectedly extinguish or the sensor no
longer detects a ame.
LOW WATER PRESSURE
START UP
The appliance will activate from a
water flow of 3lt/min. This makes
it suitable for low water pressure
applications.
OVER PRESSURISATION/
FREEZING PROTECTION
The appliance will automatically protect
itself by releasing pressure if the water
supply is over 10 Bar (this should be
manually set to lower pressures see
page 13).
SUITABLE FOR INDOOR AND
OUTDOOR INSTALLATION
This geyser can be installed indoors (with
correct ventilation) or outdoors increasing
installation options.
AUTOMATIC GAS ADJUSTMENT
The appliance will automatically adjust its
gas usage depending on the water usage,
using less gas when you use less water,
making the appliance more ecient.
Functions & Features

Page 8 of 30 Dewhot | Gas geyser manual
Appliance Safety instructions
PROPER VENTILATION
To avoid the risk of re, explosion, or
asphyxiation never operate the gas geyser
unless it is installed properly and has
adequate air supply. Make sure the ue
terminal is installed properly for the initial
start-up, check it annually thereafter.
FLAMMABLE MATERIALS
DO NOT handle, use or store combustible
materials near to the gas geyser.
WEATHER BOX AND FLUE
For indoor or outdoor installation this
geyser should be installed with a ue. For
any outdoor installation a weather box
should be installed with a ue.
WATER TEMPERATURE
SETTING
Safety and energy savings need to be
considered when setting the water
temperature . Water temperatures above
52°C can cause severe burns.
Refer to page 16.
1. Households with small children, disabled
or elderly people need to set the
temperature to 49°C or lower
2. Maximum water temperature occurs
when the burner is on. To see the water
temperature look at the front control
panel of the gas geyser.
3. The Factory default water setting is 41°C
and this setting can be adjusted on the
control panel.
4. The gas geyser has a heating range
between 38°C and 60°C.
TIME/TEMPERATURE EXPOSURE RESULTING IN BURNS
Hot water can create severe burns, we should rarely exceed the temperatures below
49°C More than 5 minutes
52°C 1.5 to 2 minutes
55°C +/- 30 seconds
57°C +/- 10 seconds
60°C less than 5 seconds
63°C less than 3 seconds
66°C +/- 1.5 to 2 seconds
69°C +/- 1 second

Page 9 of 30
Dewhot | Gas geyser manual
Dewhot | Gas geyser manual
NATURAL AND LP GAS
Both LP and natural gas are odoured to
help detect leaks.
Appliances using LP gas are dierent from
natural gas models. A natural gas geyser
can not function safely on LP gas and vice
versa.
Do not try to convert the gas geyser from
a natural gas to a LP gas appliance and vice
versa. This could damage the appliance,
cause injuries or res. Never connect the
gas geyser to a fuel type that is not in
accordance with the appliance’s data table.
WHEN DETECTING A LEAK ON
YOUR INSTALLATION
LP gas is twice as heavy as air and may
accumulate in low lying areas and cavities.
Before opening the hot water tap to test
your gas geyser have your installer check
all gas ttings and connections. Bubbles
indicate a leak.
1. Do not attempt to nd the cause
yourself and turn o the gas supply in
nding a leak.
2. Do not ignite any appliance.
3. Do not touch any electrical switch.
4. Evacuate the house immediately with
your family and pets.
5. Leave the doors open for ventilation and
contact the gas supplier, registered LP
Gas Installer or Fire Department.
6. Stay away from the house (or building)
until the service call has been made,
the leak is xed and the space has been
declared as safe.
7. Ask the installer to show you where the
gas shut-o valve is and how to use it.
8. Turn o the manual shut-o valve if
the gas geyser has been subjected to
overheating, re, ood, physical damage
or if the gas supply fails to shut o.
Gas detectors are highly recommended
and they must be installed in accordance to
the detector manufacturer’s regulations.
GAS SUPPLY
1. The gas type should match the
specication table. This is a low pressure
gas applinace and the appropriate
regulator should be used.
2. Ensure there is sucient gas pressure
(2,8kPa) for the gas supply.
3. The gas line should be equipped with a
shut o valve.
4. At least a soapy solution must be used
to check all connections and ttings for
gas leaks.
5. The COC should be issued and signed
after the installation has been inspected.

Page 10 of 30 Dewhot | Gas geyser manual
Installation instructions
LFLUES AND COVERS
• The gas geyser should be installed with
a 110mm solid or exble ue and the
applinace should be close to the ue
termination to avoid unnecessary elbows
and excessive ue length. A ue cowl
should be used if installed outdoors to
prevent rain from entering the geyser.
• Venting must be installed as outlined in
SANS 1539.
• Make sure the ue terminal is
installed properly with all parts of the ue
facing upward to allow hot air to escape.
Always use a cowl if the ue is installed
outdoors.
• The ue will expell warm air and water
vapour, do not install the terminal of
the ue near areas/objects that can
be damgeded from the above or are
combustible. (see gas geyser location)
MOUNTING THE GAS GEYSER
Install the appliance in a place that allows for
easy access for future servicing and replacing
batteries.
Use at least 8mm concrete plugs and screws
to mount the gas geyser to the wall. In the
case of dry walling use dry wall anchors.
WATER SUPPLY
This appliance must only be used with the
following water supply requirements:
1. Clean, potable water free of corrosive
chemicals, sand, dirt, or other
contaminants.
2. With inlet water temperatures above 0°C,
but not exceeding 45°C
3. Free of lime and scale deposits
4. DO NOT reverse the hot and cold water
connections, this will not allow the gas
geyser to function.
GAS GEYSER LOCATION
1. Close to ue the extraction area .
2. Protected from freezing temperatures.
3. Clear 800mm of space from
combustible surfaces.
4. Suciently ventilated.
5. Free of corrosive elements and ammable
vapours.
6. Have sucient space to service the
appliance.
7. It should be securely mounted to the wall.
8. Installed at least 1400mm o the ground.

Page 11 of 30
Dewhot | Gas geyser manual
Dewhot | Gas geyser manual
VENTILATION
REQUIREMENTS
Ventilation required for this gas water
heater is two vents of 3cm2 per Mj of gas
consumption. This equates to a total of
two vents of 218cm2 each - one installed
at high level and one at low level.
WATER SUPPLY
CONNECTIONS
Plumbing should be carried out by
a qualied plumber. Use approved
plumbing materials only. The diameter
of the pipe lines should be a minimum of
1/2” copper or pex piping.
To conserve energy and to prevent
freezing, insulate both the cold and the
hot water supply lines. DO NOT cover the
drain valves.
WATER PRESSURE
GUIDELINES
Operation of the gas geyser requires a
minimum water pressure of 14 psi (0,5
Bar) and a minimum water ow rate of
2.5 Litres/min.
1. For long pipe runs water pressure can
drop and additional water pressure may
be required.
2. When the water is supplied from a
water tank, the height of the tank, the
diameter of the pipes and their relation
to water pressure, should be taken into
consideration.
3. For gravity fed water 5 meters head is a
minimum requirement.
GAS SUPPLY LEAK TESTING
1. The gas geyser and its gas connections
must be tested for leaks at the normal
operating pressures before using it.
2. Turn on the gas shut-o valve(s)
3. Use the soapy water solution to test
for leaks at all connections and ttings.
Bubbles indicate a gas leak that must
be xed.
4. Once the appliance is operating, the
factory connections also need to be
tested for leaks.

Page 12 of 30 Dewhot | Gas geyser manual
WARNING
Never use an open ame to test for gas
leaks as this could result in property
damage, personal injury and or death.
VENTING/FLUEING
DO NOT connect the gas geyser to an
existing vent or chimney, it must be
vented/ued separately from any
other appliances.
When installing a gas geyser a minimum of
1 meter is required from any
venting system.
DRAINING THE
CONDENSATION IN THE FLUE
In cold conditions, installations with
long horizontal or vertical runs may
accumulate condensation in the ue,
install condensation traps and drains to
avoid water from going back into the
gas geyser.
IMPORTANT TIPS
If the water ow is too slow, the gas
geyser will not ignite. Keep the shower
head/outlets clean from debris that
reduces ow rate.
To keep the water pressure balanced
add a 400-600kpa pressure regulating
valve on the cold water supply for
municipal water feeds. Install a shuto
valve near the inlet of the gas geyser for
service and draining purposes.
Installation of demountables is
recommended on the hot and cold water
lines, so that the gas geyser may easily
be disconnected for servicing.
Install a non-return on the outlet of the
gas geyser to prevent water hammer.
Do not solder the HOT or COLD water
connections near to the gas geyser. If
solder connections are to be used, solder
the tting to the adapter before tting
the adapter to the water connections on
the geyser. Any heat applied to the water
supply ttings will permanently damage
the internal components of the gas geyser.
Hot water outlet connections between
the gas geyser and the usage points
should be as short as possible.
DO NOT use lead or plastic pipe. To
save energy and reduce heat loss we
recommend insulating the water piping.
NOTE The ow rate of hot water may
vary when more than two taps or
xtures are being used at the same time.

Page 13 of 30
Dewhot | Gas geyser manual
Dewhot | Gas geyser manual
Installation saftey instructions
1. Inspect the gas pipes and exible hoses
regularly. If you nd joints that are not
tightly secured or if there are cracks,
you should stop using the appliance and
perform the necessary maintenance.
2. Turn o the gas shut-o valve if your
gas geyser has been subjected to over
heating, re, ood, physical damage
or if the gas supply fails to shut o.
3. Do not allow combustible materials
such as newspaper, rags or mops to
accumulate near the appliance.
4. Do not store or use petrol or other
ammable vapours and liquids, such
as adhesives or paint thinners, in the
vicinity of this or any other
gas appliance. If such ammables
must be used, open doors and
windows for ventilation.
5. Appliances in the vicinity should be
shut o to avoid vapours igniting
from the gas burner. Flammable
vapours can be drawn by air currents
from surrounding areas to the inlet of
gas geyser.
ADJUSTING THE OVER
PRESSURISATION VALVE (OPV)
FOR FREEZING TEMPERATURES
When you have done a new installation
and have connected the water, then you
can use a small or medium at screw
driver to UNSCREW the grubscrew in the
hollow centre of the over-pressurisation
valve until the water drips out.
Then screw it BACK IN 1 full turn. This will
mean that the over-pressurisation valve
is set to the your specic water pressure
supply and in the event of the water in
the pipes freezing the valve will push out
a small amount of water and allow the
water to freeze in the geyser without
causing damage.

Page 14 of 30 Dewhot | Gas geyser manual
Operating instructions
1. Open the battery box underneath the
geyser and insert one D cell battery,
paying attention to polarity
2. Open the cold water valve that has
been installed on thwe cold water inlet
pipe or turn on the main water supply.
Open the hot water tap which your
new geyser now feeds. You should hear
the water owing through the geyser, if
the batteries are installed correctly you
will hear the geyser start to ignite if the
gas does not come through it will turn
itself o – this is one cycle. To initiate
another cycle turn the tap o and then
back on again.
3. You can now open the gas cylinder
and any gas shut o valves installed on
the gas line. There may be an air lock
inside the gas line especially for gas
piping which is longer than three to ve
meters. To get rid of this airlock you will
have to run the geyser through multiple
cycles until the gas reaches the burners,
it will then ignite. should this not work
after three cylces use the gas bleeder
valve to bleed the gas through.
4. You can adjust the temperature of
your new gas geyser by using the
digital control panel
5. Try setting your gas geyser between
40-45 degrees Celsius. You should not
need to add “much” cold water if any
at all. This way you are maximizing
your eciency by not using more gas
than you need to by overheating the
water. For longer runs in water pipe you
may need to make this temperature
slightly higher.
6. This gas geyser may only be installed
in a room where that room meets the
specic ventilation requirements of
SANS 10087:1. If you are unsure please
call the Dewhot oces to clarify.
7. Ventilation required for this gas water
heater is two vents of 3cm2 per Mj
of gas consumption. This equates to
a total of two vents of 218cm2 each -
one installed at high level and one at
low level.
8. This gas geyser must be connected
to a ue to evacuate the combustion
products to the outside of the building.
If the gas geyser is installed outdoors it

Page 15 of 30
Dewhot | Gas geyser manual
Dewhot | Gas geyser manual
Operating warnings
• Don’t use the gas geyser in a sealed
room or room with no air circulation
(see ventilation instructions on page 12).
• If you nd a gas leak, turn o the
gas valve immediately. If the room
smells of gas, turn o the gas water
heater and do not touch any electrical
appliances or switches or turn on
any hot or cold water taps. Call your
installer immediately to determine
the fault.
• When leaving the premises for
extended periods, turn o your
gas supply and turn o the gas geyser
in the event of a hot water leakage
the geyser will not turn on.
• The body of the gas geyser can get hot
during operatuon, do not touch any
part of the gas geyser, except for the
control panel
• Do not put any foreign objects in the
exhaust port, air inlet or on top of
the gas geyser to avoid incomplete
combustion which results in posioning.
• Should you notice a yellow ame which
indicates abnormal combustion you
should close the gas valve right away
and then contact the installer.
• Before outdoor temperatures reach
below zero degrees make sure the
remaining water is emptied out of the
gas geyser to avoid it freezing (Set your
OPV refer to page 13).

Page 16 of 30 Dewhot | Gas geyser manual
The gas geyser temperature can be
regulated by adjusting the setting on the
front of the control panel. Safety factors
should be considered so please read and
follow the warnings outlined on page 8.
Mixers can be used to adjust the
temperature at the water outlet.
When the burner is switched on,
maximum water temperatures are
reached. The water temperature is
determined by turning on a hot water
tap. Water temperatures at the tap will
vary depending on the weather and
length of piping from the gas geyser,
the longer the run in pipe the cooler the
water will come out of the shower head.
Set the temperature as required by
pressing the UP or down arrows on the
temperature button (also see page 17).
By pressing the UP or DOWN you
buttons will adjust the temperature
point by 1°C increments.
Water Temperature settings
ON/OFF UP DOWN

Page 17 of 30
Dewhot | Gas geyser manual
Dewhot | Gas geyser manual
SETTING YOUR GAS
GEYSER TO THE CORRECT
TEMPERATURE
The gas geyser should be set to such a
temperature that you should not have to
add too much cold water. If you set the
temperature too high and have to cool
it down using the cold water, you have
eectively wasted gas. Try set the geyser
so that you only have to open the hot
water tap only.
Start by setting the geyser to 42°C for
pipe runs shorter than 3m. If your pipe runs
are from 3-5m try setting the geyser at
43°C and for pipe runs longer than 5m try
setting the geyser at 45°C. If you nd these
temperatures are not satisfactory then
increase the temperature by 1-2°C at time
until you feel the water is hot enough.
The hottest water temperature will be
from the hot water tap closest to the
gas geyser.
Always remember to test the water
temperature with your hand before use
and remember that hotter water settings
increase the risk of injury.
The gas geyser is tted with a device that
will shut o the gas supply to the burner
if the appliance exceeds normal operating
temperatures at about 75 °C
The appliance won’t operate with a water
ow of less than 3 litres/minute.
If this occurs, increase the water ow.
A GUIDE LINE OF
SHOWERING TEMPERATURES
Body temperature: 35-37 °C
Summer time comfortable showering
temperatures: 35-38°C
Warm shower in winter: 39°C
Hot showering temperature in winter
42°C (most preferred showering
temperature)
Very hot showering temperature in
winter: 44°C
For a bath temperature in winter: 48-50°C
Bare in mind a geyser showing 40°C will
not be the same temperature at the
shower head as it will loose heat travelling
through the pipes, the further the run in
pipes the more heat will be lost. Also bare
in mind the slower the ow rate the more
heat will be lost through the pipes as the
water spends more time travelling to the
shower loosing greater amounts of heat.

Page 18 of 30 Dewhot | Gas geyser manual
GENERAL MAINTENANCE
If your gas technician maintains your gas
geyser you should not have any issues with
it for years.
We recommend that you periodically check
the burner, relief valve, water lter and
ue system.
This needs to be done by a certied installer.
A maintenance program is advisable.
1. Inspect the area around the gas
geyser to ensure that its in a safe
operating environment.
2. Make sure that the appliance has not
been damaged. If there are traces
of damage or denting contact your
supplier to check that the appliance is
still functioning properly.
3. Check for any abnormal sounds while
operating your appliance. A light
humming sound is normal from time to
time.
Check for gas/ water leaks.
4. The cold water supply lters should be
cleaned once a year.
5. Perform regular maintenance on the
geyser to prevent carbon monoxide
dangers, excessive hot water
temperatures or other potentially
hazardous conditions.
DO NOT
1. Continue to use the gas geyser if you feel
that there is something wrong with it.
2.
3. Allow children to operate or handle
the appliance.
After you have checked, maintained and/
or cleaned the appliance, make sure that it
is working properly by turning on the hot
water tap.
COASTAL CORROSIVE
ENVIROMENTS
For geysers installed near the coast, get
your gas installer to remove the cover and
spray electrical contact cleaner on all the
electronic contacts, after the electrical spray
has dried up you can spray Q30 or any other
kind of electrical sealant to seal the joins
and prevent corrosion from entering the
electronics. This is highly advised and can be
performed at any location inland or coastal.
Do not perform this step if the geyser is on.
Maintenance and cleaning

Page 19 of 30
Dewhot | Gas geyser manual
Dewhot | Gas geyser manual
GENERAL CLEANING
1. Clean the appliance and remote control
by using a damp soft cloth only. Gently
wipe the surfaces of the appliance and
any remaining moisture with a dry
soft cloth.
2. Do not store household items near or on
top of the appliance
3. inlet water lters should be cleaned on a
regular basis.
4. DO NOT scrub the appliance with
a brush.
5. Use only water, any chemicals can
damage the surface of the appliance.
6. DO NOT remove any labels, including the
rating table when cleaning or servicing.
7. DO NOT splash water on the remote
controls when cleaning.
CLEANING THE
WATER FILTER
• Turn the appliance o
• Turn the water supply to the
appliance o.
Unscrew the water tting and pull the
lter out.
• Remove particles - use a soft brush and
rinse it with running water.
• Put the lter back and screw it in
• Turn on the second the cold
water supply.
CAUTION
Cleaning of the main burner should always
be performed by Registered LPG Installer.
A compressor can be used to clean
the burner.
BURNER INSPECTION
Visually check the main burners annually.
Use the sight glass to check the ame
picture, the ame should be a clean blue
ame only.
If a yellow ame occurs, the gas geyser
should be shut down and you should call a
qualied installer to assess the appliance.
Check to make sure that the air supply and
the vent terminal have not been blocked
or contain debris.
VACATION AND EXTENDED
SHUT-DOWN
If the gas geyser is left for an extended
period of time, the power and gas to the
appliance should be turned o.
The gas geyser and piping should be
drained if they could be subjected to
freezing temperatures over this period.
After a long shut-down period, the gas
geyser needs to be serviced and checked.

Page 20 of 30 Dewhot | Gas geyser manual
Symptoms and faults
Symptom FAULT
Pilot comes on but ignitor
continues to tick
Partially blocked pilot tube - the ame out
sensor is not in the ame
faulty ame out sensor
or after heavy rain the controller can be
wet, this will sort itself once dried o
The pilot is ring and ring but
does not take a ame, an E1 error
comes up and there is a faint
smell of gas
Check the pilot ame tube is not blocked or
partially blocked by a spiders web, remove
tube and clean it out, always check the
pilot jet at the same time
Unit res continuously without a
ame coming on or showing
an error
Faulty controller
Faint ring and PA, BA or 6A
comes up on the screen Flat batteries
The geyser ame comes on and
runs up to temperature then
drops away and tries
to re-ignite. The process repeats
and either no error comes up on
the screen or an E8 error
is shown
LCD panel is faulty or the control box is wet
normally after a storm
Wait at least a day for the unit to dry
before lodging a service call
Only 35-38 degrees reached
on the LCD screen
The water ow may be too high, reduce it
and place a 400kPa pressure reducing valve
on the cold water line
The regulator may be undersupplying gas,
Check the gas inlet pressure is operating at
2,8 kPa while the applinace is running