OPERATING AND

INSTALLATION MANUAL
TANK-TYPE WATER HEATER FOR VERTICAL
MOUNTING

Electric water heaters

OKCE 50
OKCE 80 OKCE 200 OKHE 80
OKCE 100 OKHE 100
OKCE 125 OKHE 125
OKCE 160 OKHE 160

Družstevní závody Dražice-strojírna s.r.o.

Dražice 69, 294 71 Benátky nad Jizerou
tel.: +420 / 326 370 911
e-mail: export@dzd.cz
CONTENTS
1 PRODUCT TECHNICAL SPECIFICATION ....................................................................................................... 4
1.1 FUNCTION DESCRIPTION ................................................................................................................... 4
1.2 ADVICE FOR CUSTOMERS .................................................................................................................. 4
1.2.1 HOT WATER CONSUMPTION ..................................................................................................... 4
1.2.2 ENERGY SAVING......................................................................................................................... 4
1.2.3 EMERGENCY POWER CONSUMPTION ....................................................................................... 4
1.3 DESIGN AND GENERAL HEATER DIMENSIONS................................................................................... 6
2 OPERATION AND FITTING INSTRUCTIONS ................................................................................................. 9
2.1 OPERATING CONDITIONS .................................................................................................................. 9
2.2 WALL MOUNTING .............................................................................................................................. 9
2.3 PLUMBING FIXTURE ......................................................................................................................... 10
2.4 ELECTRICAL INSTALLATION .............................................................................................................. 12
2.4.1 GENERAL INFORMATION FOR ELECTRICAL INSTALLATION ..................................................... 12
2.5 OPERATING ACTIVITY ...................................................................................................................... 13
2.6 FIRST COMMISSIONING ................................................................................................................... 13
2.7 PUTTING OUT OF SERVICE, DISCHARGE .......................................................................................... 14
2.8 INSPECTION, MAINTENANCE & CARE FOR THE APPLIANCE ............................................................ 14
2.9 MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES .......................................................... 15
3 OPERATION OF THERMOSTAT ................................................................................................................. 16
3.1 OPERATING DEVICES OF THE HEATER ............................................................................................. 16
3.1.1 TEMPERATURE SETTING .......................................................................................................... 17
4 IMPORTANT NOTICES .............................................................................................................................. 17
4.1 INSTALLATION REGULATIONS.......................................................................................................... 17
4.2 TRANSPORT & STORAGE INSTRUCTIONS ........................................................................................ 18
4.3 DISPOSAL OF PACKAGING MATERIAL AND NON-FUNCTIONING PRODUCT.................................... 18
5 PRODUCT ACCESSORIES .......................................................................................................................... 18

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 CAREFULLY READ THIS MANUAL BEFORE INSTALLING THE WATER HEATER!

Dear Customer,

Družstevní závody Dražice - strojírna s.r.o., would like to thank you for
your decision to use a product of our brand. With this guide, we will
introduce you to the use, construction, maintenance and other
information on electrical water heaters.

The product is not intended to be controlled by

a) people (including children) with reduced physical, sensual or mental capacities, or
b) people with insufficient knowledge and experiences unless supervised by responsible person,
or unless properly instructed by such responsible person.

The manufacturer reserves the right for engineering modification of the product. The product is designed
for permanent contact with drinkable water.

It is recommended to use the product in indoor environment with air temperatures from +2 °C to +45 °C
and a relative humidity up to 80 %.

Product’s reliability and safety is proven by tests implemented by the Engineering Test Institute in Brno.

Made in the Czech Republic.

Meaning of pictograms used in the Manual

Important information for heater users.

Abiding by the recommendations of the manufacturer serves to ensure trouble-free operation

and the long service life of the product.

Caution!
Important notice to be observed.

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1 PRODUCT TECHNICAL SPECIFICATION
1.1 FUNCTION DESCRIPTION
Tank type water heater (the heater hereinafter) is designed for the accumulation heating of service water
by electric energy. Water is heated by an electric element in an enameled thermally insulated tank at the
time defined by the power supplier. The element is at the time of heating controlled by a thermostat
the temperature of which can be adjusted continuously (within the range between 5 °C and 75 °C). Once
the selected temperature is reached, heating interrupts automatically. Water accumulated in the tank is then
used for consumption. The tank keeps constant pressure of water from the water main. If the combination
faucet hot water valve is opened, water from the water supply conduit pressed out by cold water pressure
flows out of the heater. Hot water flows out through the top part, and water flowing in remains in the bottom
part of the heater. Pressure principle allows hot water withdrawal at any place from the heater.

1.2 ADVICE FOR CUSTOMERS

1.2.1 HOT WATER CONSUMPTION
Consumption of hot water in households depends on the number of people, amount of sanitary
equipment, length, diameter and insulation of piping in the flat, or on individual habits of users.
The cheapest option of water heating comes at the time when the electricity rate is reduced.

Find out in what time intervals your electricity supplier provides reduced tariff and, depending
on that information, select relevant volume and power input of the heater so that your hot
water consumption covered the needs of your household.

1.2.2 ENERGY SAVING

The heater is insulated with quality polyurethane Freon free foam. Set the temperature
of the heater's thermostat to that level only that you need to run your home. Thus you will
reduce electricity consumption, as well as the amount of lime sediments on the walls of
the receptacle and on the electric body.

1.2.3 EMERGENCY POWER CONSUMPTION

According to current legislation, the standby consumption is stated in the value of annual
consumption of electric energy (kWh), which is measured according to the corresponding load
profile and calculated according to the formulas and requirements of EU Regulation
No. 812/2013.

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 OKCE 80 OKCE 100 OKCE 125 OKCE 160
TYPE OKCE 50 OKCE 200
OKHE 80 OKHE 100 OKHE 125 OKHE 160
97 122 149
VOLUME l 49 75 199
100 121 153
MAX OPERATING
OVERPRESSURE bar 6
IN THE TANK
ELECTRICAL
1/N/PE ~ 230V/50Hz
CONNECTION
RECOMMENDED
16 A
BREAKER
INPUT W 2200

EL. PROTECTION IP 44

MAX TEMPERATURE TV °C 80

RECOMMENDED HOT
WATER (HW) °C 60
TEMPERATURE
HEIGHT OF THE 757 902 1067 1255
mm 585 1300
HEATER 740 885 1050 1235
HEATER DIAMETER
mm 524 524 524 524 524 584
(only OKCE)
THE HEATER
DIMENSION
mm 520x550
width x depth
(only OKHE)
MAX WEIGHT
32 39 43 49
OF THE HEATER kg 28 66
34 38 45 51
WITHOUT WATER
TIME OF EL. HEATING 3.9
hrs 1.3 2.0 2.6 3.2 5.3
FROM 10 °C TO 60 °C 4.0
138.70 165.41 231.10 242.83
MIXED WATER V40 l 80.84 331.26
124.83 151.66 180.40 219.82

LOAD PROFILE M M M M L XL

ENERGY EFFICIENCY
C C C C C C
CLASS
38 38 36 39
ENERGY EFFICIENCY % 38 38
37 37 38 38
ANNUAL
1342 1362 1409 2622
CONSUMPTION OF kWh 1365 4403
1391 1395 1353 2715
ELECTRIC ENERGY

Table 1

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1.3 DESIGN AND GENERAL HEATER DIMENSIONS
The heater tanks are made of a steel plate and tested by 1.5 multiple of the operating pressure values.
The inside of the receptacle is enameled. A flange is welded onto the bottom of the tank with a flange lid
screwed to it. A sealing ring is inserted between the flange lid and the flange. Thermowells for placing
a heating element, thermostat sensors and safety fuses are located in the flange lid. An anode rod is mounted
onto the M8 nut. Electric wiring is placed underneath the plastic removable cover. Description of basic parts
of the heater - Figure 1. Heater dimensions - Figure 2 and Table 2, Figure 3 and Table 3.

Figure 1

1. Temperature indicator
2. Heating element well
3. Ceramic heating element 2200 W
4. Service thermostat with external control and safety pipe
5. Electric installation cover
6. Cold water supply pipe
7. Thermowell
8. Hot water withdrawal pipe
9. Mg anode
10. Enamelled steel receptacle
11. Polyurethane insulation
12. Heater shell

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OKCE 50, OKCE 80, OKCE 100, OKCE 125, OKCE 160, OKCE 200

Upper and lower Hinge 200 l

4 anchoring screws
Dimensiions 450mm and F Upper hinge 50-160 l
check before drilling 2 anchoring screws

Figure 2

 3/4" outer

OKCE 50 OKCE 80 OKCE 100 OKCE 125 OKCE 160 OKCE 200

A 585 757 902 1067 1255 1300

B 562 562 562 562 562 617
C 14 14 14 14 14 14
D 524 524 524 524 524 584
E 440 605 725 760 1000 806
F 369 508 654 682 925 600
H 135 142 167 297 245 480
K 116 116 116 116 116 116
R 450 450 450 450 450 450

Table 2

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OKHE 80, OKHE 100, OKHE 125, OKHE 160

Figure 3

OKHE 80 OKHE 100 OKHE 125 OKHE 160  3/4" outer

A 740 885 1050 1235

B 550 550 550 550
C 19 19 19 19
D 520 520 520 520
E 582 727 757 1000
F 464 605 638 880
H 148 148 283 225
K 117 117 117 117
R 450 450 450 450

Table 3

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2 OPERATION AND FITTING INSTRUCTIONS
2.1 OPERATING CONDITIONS
The tank shall only be used in accordance with the conditions specified on the power plate
and in instructions for electric wiring. Besides legally acknowledged national regulations
and standards, also conditions for connection defined in local electric and water works have to
be adhered to, as well as the installation and operation manual.

The temperature at the place of heater installation must be higher than +2 °C; and the room
must not freeze. The appliance has to be mounted at a convenient place, it means that the
appliance must be easily available for potential necessary maintenance, repair or replacement,
as the case may be.

If water is strongly calcareous we recommend that any of the common decalcifying devices was
installed with the appliance, or that the thermostat was set to the minimum operating
temperature of 55 °C (setting to position „OPTIMUM“) - Figure 11. For proper operation,
drinkable water of adequate quality shall be used. To avoid potential sediments, we recommend
that the device was installed together with a water filter.

2.2 WALL MOUNTING

Prior to the mounting check the bearing capacity of the wall and the material it is made of,
considering the weight of the heater filled with water. Depending on the wall material choose
adequate fixtures. We recommend entrusting wall mounting and anchoring to a specialist
company or consult the suspension with a building specialist. When mounting the anchor bolts
follow the guide provided by the anchor bolts' manufacturer.

Mount the anchors by the dimensional drawing (Figure 2, Figure 3) in 450 mm spacing. The heater verticality
after the release of the connecting screws can be aligned by means of slight turning. Double check
the torque of the suspension bolts on the heater and suspend the heater. Using the detent support
in the bottom part of the heater make sure it runs in parallel with the wall at the heaters OKHE 80 - 160 l!

Figure 4

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Universal suspension
The use of the suspension even for the screw spacing during the replacement with a heater of another type.
The heater verticality after the release of the connecting screws can be aligned by means of slight turning.

Figure 5
If the hot water heater is mounted in a tight, small space, or in an intermediate ceiling, etc., you
have to make sure that the connecting side of the appliance (connections to water supply, area
for electric plugging) remained accessible and no heat accumulation occurs. Free space of up to
600 mm from the bottom edge of the heater has to be available under the heater. When
mounted directly under the ceiling, the distance from the ceiling has to be 50 mm at least.

If the water heater is mounted in enclosed areas, inter-ceilings, built-in structures, and recesses,
ensure sufficient access to service fittings, electrical terminal boards, anodes and manholes.
Minimum spacing from manhole is 600 mm.

2.3 PLUMBING FIXTURE

The heater connects to water distribution tubes with G 3/4“ thread in the bottom part
of the heater. Blue - cold water supply, red - hot water outlet. For potential disconnection
of the heater, the service water inlets and outlets must be provided with screw coupling Js 3/4“.
The safety valve is mounted on the cold water inlet identified with a blue ring.

The heater must be equipped with a membrane, spring-loaded safety valve. Safety valves with
fixed pressure settings from the manufacturer are used for the assembly. Each individually
lockable heater must be fitted with a cap on the cold water inlet, a test valve or a stopper
to check the operation of the check valve, with a check valve and a relief valve (Figure 6).
The safety valve with a check valve is supplied with the heater.

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 It is necessary to check the safety valve each time before putting it into operation. It is checked
by manual moving of the membrane from the seat, turning the make-and-break device button
always in the direction of the arrow. After being turned, the button must click back into a notch.
Proper function of the make-and-break device results in water draining through the safety valve
outlet pipe. In common operation, such a check needs to be implemented at least once a month,
and after each heater shutdown for more than 5 days. Water may be dripping off the drain pipe
of the safety valve; the pipe must be open into the air, pointed down; environment
temperatures must not drop below zero.

Find necessary pressure values in the below - Table 4.

Heaters must be provided with a discharge valve mounted on the cold service water inlet to the heater for
potential disassembly or repair. When assembling the security equipment, follow the standard.

ALLOWABLE
SAFETY VALVE MAXIMUM
OPERATING
START-UP PRESSURE IN
OVERPRESSURE
PRESSURE COLD WATER
OF WATER
[MPa] PIPES [MPa]
HEATER [MPa]

0.6 0.6 up to 0.48

Table 4

Figure 6

Figure 7

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2.4 ELECTRICAL INSTALLATION
2.4.1 GENERAL INFORMATION FOR ELECTRICAL INSTALLATION
Perform the connection according to the scheme. Factory connection must not be changed! (Figure 9)
the electric wiring casing remove the partition corresponding with the input wire diameter of Ø8 or Ø10
(Figure 8). The degree of protection of electric parts of the heater is IP 44. Power input of electric element
is 2200 W.

Ø10
Ø8
Ø8
Ø10

Figure 8
It is necessary to observe the below requirements during the electric wiring.
• The electric wiring scheme is attached to the water heater on the side of the electric
installation guard (Figure 9)
• Connection, repairs, and wiring inspections may only be implemented by a company (person)
authorized to such activity.
• Expert connection must be confirmed on the warranty certificate.
• The heater is connected to the 230 V/50 Hz electrical network using a fixed moving conductor
with the circuit breaker (protector).
• Installations in bathrooms, laundry rooms, rest rooms and showers, must be in compliance
with standard.
• The degree of protection of electric parts of the heater is IP 44.
• Adhere to the protection against electric shock injury according to standard.

Figure 9

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2.5 OPERATING ACTIVITY
After the heater is connected to electric network, the heating element starts heating water. The element
is turned on and off by a thermostat. After reaching the temperature set, the thermostat switches off
the electric circuit and discontinues water heating. The control light signals if the element is in operation
(light is on) or if it is off (the light goes out). In case of longer operation without using the heated volume,
the thermostat has to be set to position 5 °C to 10 °C (set the “snowflake” symbol on the thermostat selector)
to avoid its freezing, or electricity supply to the heater has to be switched off.

2.6 FIRST COMMISSIONING

Before opening the power supply, the tank must be filled with water. The process of first heating
must be executed by licensed professional who has to check it. Both the hot water outlet pipe
and safety armature parts may be hot.

During the heating process the pressurized connection water that increases its volume due to
heating must drip off the safety valve. In non-pressurized connection water drips off the
overflow combination faucet. When heating is finished, the set temperature and the actual
temperature of consumed water should be roughly equal. After connecting the heater to the
water main and electrical power system, and after checking the safety valve (following the
instructions attached to the valve), the heater can be put into operation.

Before fist putting into service or after a longer shutdown the appliance has to be rinsed out and
flushed yet before heating is activated. Before heating starts, the tank must be completely filled
with water and the system properly flushed and vented. First heating of the tank has to be
watched.

Procedure of putting the heater into operation:

1. Check the water main and wiring. Check proper placement of operating and safety thermostat
sensors. Sensors has to be installed in to the sink as deep as possible - following the possibilities of
each capillary, controlling thermostat has to be installed as first sensor in to the capillary, following
by the safety thermostat as the second sensor installed in to the capillary.
2. Open the hot water valve on the combination faucet.
3. Open the cold water inlet valve to the heater.
4. As soon as the water starts running through the hot water valve, the heater is filled, and the valve
can be closed.
5. In case of leakage (of flange lid), we recommend that the flange lid bolts are fastened. Screws has to
be tightened by cross, tightening moment 15Nm.
6. Screw down the electric installation guard.
7. When hot service water is heated by electric energy, switch on the power supply.
8. When commencing operation, flush the heater until the cloudiness in the water is gone.
9. Make sure to fill in properly the warranty certificate.

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2.7 PUTTING OUT OF SERVICE, DISCHARGE
If the hot water heater is put out of service for a longer time, or if it is not going to be used it
has to be drained and disconnected from the electric supply network. The switch for the supply
lead or the fuse cut-outs have to be shut off.

At places with permanent risk of frost the hot water heater must be drained before the cold
season starts if the appliance remains out of service for several days and if the power supply is
disconnected.

Drainage of service water shall be performed after closing the shut-off valve in the cold water
supply piping (through the discharge valve for safety valve combination), and with simultaneous
opening of all hot water valves of connected fittings (water can be also drained through safety
valve; for that purpose, the safety valve is turned to the "Check" position). Hot water may
outflow during the drainage! If there is a risk of frost it has to be considered that not only the
water in the hot water heater and in the hot water piping may get frozen but also the water in
the entire cold water supply piping. It is therefore advisable to drain all fittings and piping that
carry water, up to the part where the house water meter is installed (connection of the house
to water main) which is not jeopardized by frost. When the tank is to be used again, it has to be
filled with water and one needs to make sure that the water flowing out at the hot water valves
did not contain any bubbles.

2.8 INSPECTION, MAINTENANCE & CARE FOR THE APPLIANCE

During the heating process the water that increases its volume during the heating must visibly
drip off the safety valve outlet (in non-pressurized connection this water drips off the
combination faucet valve). In full heating (about 75 °C) the volumetric water gain is approx. 3 %
of the tank capacity. The function of the safety valve has to be checked regularly. If the safety
valve control knob is lifted or turned to the “Control” position, the water must flow out easily,
without any obstacles, from the safety valve element to the outfall line. In common operation,
such a check needs to be implemented at least once a month, and after each heater shutdown
for more than 5 days.

Attention! In doing so, the cold water supply pipe and the connection fitting of the tank may get
heated! If the hot water heater does not work, or if hot water is not withdrawn, no water shall
drip off the safety valve. If water drips, then the water pressure in the supply piping is either too
high (if higher than 4.8 bars, a pressure control valve has to be fitted), or the safety valve
is defective. Please call a specialized plumber immediately!

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 If water contains too many minerals, an expert has to come to remove the scale that forms inside
the tank, as well as free sediments. This has to be performed after one or two years of operation.
The cleaning is carried out through the hole in the flange - dismantle the flange lid and clean the
tank. A new sealing has to be used for re-fitting. Since the inside of the heater has special enamel,
which must not get in contact with the scale removing agent - do not work with a lime pump.
Remove the lime layer with a timber and suck it off or wipe it off with a clout. After that,
the appliance must be rinsed thoroughly, and the heating process is checked the same as during
the initial putting in operation. Do not use any abrasive cleaning agents (such as liquid sand,
chemicals - acid, alkaline) or dye thinners (such as cellulose thinner, trichlor, and the like) to
clean the outer shell of the heater. For cleaning use a wet clout and add a few drops of liquid
cleaning agent for household applications. Repeated heating causes lime scale settling on the
receptacle walls and mostly on the lid of the flange. Lime scale settling depends on hardness of
heated water, its temperature and on the volume of hot water used.

We recommend checking and cleaning the tank from scale and eventual replacement of the
anode rod after two years of operation. The anode life is theoretically calculated for two years
of operation; however, it changes with water hardness and chemical composition in the place
of use. Based on such an inspection, the next term of anode rod exchange may be determined.
If the anode is only blocked with sediments clean its surface and, if used up, mount a new one.
Have a company in charge of service affairs deal with the cleaning and exchanging of the anode.
When draining water from the heater, the combination faucet valve for hot water must be open,
preventing occurrence of under-pressure in the heater tank which would stop the water from
draining.

2.9 MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES

FAILURE SYMPTOM INDICATOR SOLUTION

• The temperature set on the thermostat

Water is cold • Light on
is too low; heating element failure

• No supply voltage!
• Thermostat failure
Water is cold • Light off
• Safety thermostat shut off probably due
to failed operation thermostat

• Failure of one of the coils

Water is not warm enough • Light on
in the element (2x 1100W)

Temperature of water is not

corresponding with the
• Defective thermostat
temperature set on the
control

Water is constantly dripping • High input pressure

• Light off
off the safety valve • Defective safety valve

Table 5

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 Do not attempt to repair the failure yourselves. Seek either expert or service help. It does not
take much for an expert to remove the defect. When making a repair appointment, report the
type and serial number you find on the performance plate of your water heater.

3 OPERATION OF THERMOSTAT
3.1 OPERATING DEVICES OF THE HEATER
Electrical installation cover for heaters OKCE and OKHE
Electric circuit closing indicator lamp
Thermostat knob

Figure 10
Thermostat and no other part of the control panel is not a bearing part which can be used for
any handling with the heater.

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 3.1.1 TEMPERATURE SETTING
Water temperature is set by turning the thermostat knob. The desired symbol is adjusted against the fixed
point on the control panel (Figure 11).

Fixed mark on the

control panel
Upper temperature range
limit (about 75°C)
"Ideal" temperature
(about 55°C)
Lower limit of temp. scope
(around 5°C)

"Anti-freezing" temperature
(about 10°C)

Figure 11

Adjusting the thermostat knob to the left backstop does not mean permanent shutoff of
the heating element. When the heater is in use without blocking the daily rate, we do not
recommend the temperature to be set above 55 °C. Select the "OPTIMUM" symbol as the
maximum.

4 IMPORTANT NOTICES
4.1 INSTALLATION REGULATIONS
- Without a confirmation of performed electrical installation issued by an authorized company,
the warranty certificate shall be void.
- Check and exchange the Mg anode regularly.
- You have to apply for approval of a local power supplier to connect the heater.
- No stop valves can be put between the heater and the safety valve.
- If the overpressure in the water main exceeds 0.48 MPa, a pressure control valve must be mounted
before the safety valve.
- All hot water outputs must have a combination faucet.
- Before filling the heater with water for the first time, it is recommended to fasten the flange
connection nuts of the tank. Screws has to be tightened by cross, tightening moment 15Nm.
- It is not allowed to handle the thermostat, aside from temperature resetting with a control button.
- All electric installation handling, adjustment and replacement of the regulation elements shall only
be performed by an authorized service company.

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 - The thermal fuse must not be turned off! In case of thermostat defect, the thermal fuse interrupts
electric power input to the heating element if the water temperature in the heater exceeds 90 °C.
- If you don't use the heater (hot water tank) for longer than 24 hours, or if the facility with heater
is unattended, close the cold water inlet to the heater.
- The heater (hot water tank) shall be used exclusively in accordance with the conditions specified
on the performance plate and in the instructions for electric wiring.
- The recommended operating pressure in the hot water circuit is 0.48 MPa.

Both the electric and water installation must follow and meet the requirements
and regulations relevant in the country of use!

4.2 TRANSPORT & STORAGE INSTRUCTIONS

The device shall be transported and stored in dry place and protected from weather effects with temperature
range from -15 to +50 °C. During loading and unloading the instructions stated on the packaging shall be
observed.

4.3 DISPOSAL OF PACKAGING MATERIAL AND NON-

FUNCTIONING PRODUCT
A service fee for providing return and recovery of packaging material has been
paid for the packaging in which the product was delivered. The service fee was
paid pursuant to Act No 477/2001 Coll., as amended, at EKO-KOM a.s. The client
number of the company is F06020274. Take the water boiler packages to a waste
disposal place determined by the town. When the operation terminates,
disassemble and transport the discarded and unserviceable heater to a waste
recycling center (collecting yard), or contact the manufacturer.

5 PRODUCT ACCESSORIES
The product is supplied with a safety valve and temperature indicator. The variant OKHE has in addition
rectifying (delimiting) screw M8 only with OKHE variant, fan mat  8.4 - 2pcs and nuts M8. The above parts
are packed and placed in the packaging in the top part of the heater.

It is in your own interest to check the completeness of the accessories.

10-1-2024

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