Drazice OKHE ONE 30 Specification sheet

OPERATING AND
INSTALLATION MANUAL
FLAT TANK-TYPE WATER HEATER FOR
VERTICAL MOUNTING
Electric water heaters
OKHE ONE 30
OKHE ONE 50
OKHE ONE 80
OKHE ONE 100
OKHE ONE 120
Družstevní závody Dražice - strojírna s.r.o.
Dražice 69, 294 71 Benátky nad Jizerou
Phone.: [phone]
Fax: +420 / 326 370 980
e-mail: [e-mail]

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CONTENTS
1PRODUCT 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
1.3DESIGN AND GENERAL HEATER DIMENSIONS ................................................................................. 6
2OPERATION AND FITTING INSTRUCTIONS.................................................................................................8
2.1 OPERATING CONDITIONS................................................................................................................. 8
2.2 WALL MOUNTING ............................................................................................................................ 8
2.3 PLUMBING FIXTURE ......................................................................................................................... 9
2.4 ELECTRICAL INSTALLATION ............................................................................................................ 11
2.4.1 GENERAL INFORMATION FOR ELECTRICAL INSTALLATION ....................................................... 11
2.5 OPERATION .................................................................................................................................... 12
2.6 FIRST COMMISSIONING ................................................................................................................. 12
2.7 PUTTING OUT OF SERVICE, DISCHARGE......................................................................................... 13
2.8 INSPECTION, MAINTENANCE & CARE FOR THE APPLIANCE .......................................................... 14
2.9 MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES......................................................... 15
3OPERATION OF THERMOSTAT................................................................................................................. 15
3.1 OPERATING DEVICES OF THE HEATER............................................................................................ 15
3.1.1 TEMPERATURE SETTING ............................................................................................................ 16
4IMPORTANT NOTICES .............................................................................................................................. 16
4.1 INSTALLATION REGULATIONS ........................................................................................................ 16
4.2 TRANSPORT & STORAGE INSTRUCTIONS ....................................................................................... 17
4.3 DISPOSAL OF PACKAGING MATERIAL AND NON-FUNCTIONING PRODUCT .................................. 17
5PRODUCT ACCESSORIES .......................................................................................................................... 17

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PRIOR TO THE INSTALLATION OF THE TANK, READ CAREFULLY THIS MANUAL!
Dear customer,
The Works Cooperative of Dražice – Machine Plant, Ltd., would like to
thank you for your decision to use a product of our brand. The present
instructions will introduce you to the use, construction, maintenance
and other information regarding electrical water tanks.
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%. 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 tank 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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1PRODUCT TECHNICAL SPECIFICATION
1.1 FUNCTION DESCRIPTION
The heater is designed for accumulation heating of service water using electricity. Water is heated by an
electric element in an enamelled thermally insulated tank at the time defined by the power supplier. At the
time of the heating, the element is controlled by thermostat on which the desired temperature can be set
(ranging from 5 to 74℃). 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
Hot utility water reservoir is insulated by means of top-quality polyurethane foam with zero
CFCs content. Adjust 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 element's pit.
1.2.3 EMERGENCY POWER CONSUMPTION
If no heated water is taken from the tank, a small amount of heat leaks. This loss is measured
for a period of 24 hours at the temperature of 65°C in the heater, and at 20°C in its ambient
area. The resulting value is expressed in units [kWh/24h] and indicates the amount of power
needed to maintain the set temperature.

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TYPE
OKHE ONE
30
OKHE ONE
50
OKHE ONE
80
OKHE ONE
100
OKHE ONE
120
VOLUME L 28 45 65 80 98
MAX OPERATING
OVERPRESSURE IN THE
TANK
MPa 0,6
ELECTRICAL CONNECTION V 1/N/PE ~ 230V/50Hz
RECOMMENDED BREAKER 10 A 16 A
INPUT W 1100 2000
EL. PROTECTION IP 44
MAX OPERATING
TEMPERATURE OF HOT
WATER (HW)
°C 80
RECOMMENDED HOT
WATER (HW)
TEMPERATURE
°C 60
HEIGHT OF THE HEATER mm 617 845 1112 1327 1552
HEATER DIMENSION width
x depth mm 523x318
MAX WEIGHT OF THE
HEATER WITHOUT WATER kg 22 31 46 55 62
TIME OF EL. HEATING
FROM 10°C TO 60°C hrs 1,5 1,5 22,5 3
LOAD PROFILE S M M M M
DAILY ELECTRICITY
CONSUMPTION kWh 2,69 6,25 6,4 6,56 6,55
MIXED WATER V40 L 39,4 72,2 88,8 113,1 118,2
Table 1

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1.3 DESIGN AND GENERAL HEATER DIMENSIONS
The heater tanks are made of a steel plate and tested at 0.9 MPa of overpressure. The inside of the tank is
enamelled. A flange is welded onto the bottom of the tanks 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 tone flange lid, and the safety fuses and the second
flange lids are without thermowells. 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.
1. Enamelled steel receptacle
2. Heater shell
3. Polyurethane insulation
4. The heating element well, ceramic heating unit 2000W, OKHE ONE 30 – 1100W
5. Thermostat sensor well and temperature indicator
6. Mg anode
7. Filling-in tube
8. Electric installation cover
9. Thermometer
10. Service thermostat with external control and safety fuse
11. Drain tube
Figure 1

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Technical description: OKHE ONE 30 - 120
Figure 2
OKHE ONE
30
OKHE ONE
50
OKHE ONE
80
OKHE ONE
100
OKHE ONE
120
A617 845 1112 1327 1552
B318 318 318 318 318
D523 523 523 523 523
E500 730 920 1135 1360
F350 560 750 950 1150
H110 110 190 190 190
K110 110 110 110 110
R180 180 180 180 180
Table 2
3/4" outer

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2OPERATION 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 55oC (setting to position „OPTIMUM“) - fig.9. 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.
Should you have any doubts regarding the wall bearing capacity, consult the suspension with
a building specialist.
The minimum diameter of 4 bolts for suspending the heater is 6 mm. When mounting the
anchor bolts follow the manual provided by the anchor bolts' manufacturer.
If the hot water heater is mounted in a tight, smaller 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.
Mount the water heater in vertical position. The fixing wood screws must have guaranteed
spacing t=180 mm and spacing F according to the heater volume (fig.3).
It is possible to purchase a set of hinges ONE order 102000703.

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180 mm
F
Figure 3
2.3 PLUMBING FIXTURE
Power water connects to pipes with ¾“ 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.
Each hot service water pressure heater must have a safety valve with a membrane spring.
Nominal clearance of safety valves is defined by standard. Heaters are not equipped with
a safety valve. The safety valve must be easily accessible, as close to the heater as possible. The
inlet pipes must have at least the same clearance as the safety valve. Safety valve is placed high
enough to secure dripping water drain by gravity. We recommend mounting the safety valve
onto a branch pipe. This allows easier exchange without having to drain the water from the
heater. Safety valves with fixed pressure settings from the manufacturer are used for the
assembly. Starting pressure of a safety valve must be identical to the maximum allowed heater
pressure, and at least 20 % higher than the maximum pressure in the water main (Table 3). If
the water main pressure exceeds such value, a reduction valve must be added to the system.
No stop valves can be put between the heater and the safety valve. During assembly, follow
the guide provided by the safety equipment manufacturer. Every independently closing heater
must include a shutoff, test cock, or a plug for the inspection of the backflow fitting, backflow
fitting, and safety valve on the cold water supply.
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
F
OKHE ONE 30
350
OKHE ONE 50
550
OKHE ONE 80
750
OKHE ONE 100
950
OKHE ONE 120
1150

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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. When draining the heater, use the recommended
drain valve. First, close the water supply into the heater.
Find necessary pressure values in the following (table 3). For proper safety valve operation, a backflow
valve (figure 5), must be mounted on the inlet pipes, preventing spontaneous heater draining and hot
water penetrating back into the water main. We recommend that the hot water distribution from the
heater was as short as possible to minimise heat losses. At least one demountable joint must be mounted
between the tank and every supply pipe. Adequate piping and fittings with sufficiently dimensioned
maximum temperature and pressure values must be used.
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.
Table 3
Figure 4
SAFETY VALVE
START-UP
PRESSURE
[MPa]
ALLOWABLE
OPERATING
OVERPRESSURE
OF WATER
HEATER [MPa]
MAXIMUM
PRESSURE IN
COLD WATER
PIPES [MPa]
0,6 0,6 up to 0.48
0,7 0,7 up to 0.56
1 1 up to 0.8

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Figure 5
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! (Fig.7).
In the electric wiring casing remove the partition corresponding with the input wire diameter of φ8 or φ10
(fig.6). The degree of protection of electric parts of the heater is IP 44. Power input of electric element is
2000W (OKHE ONE 50-120), 1100W (OKHE ONE 30).
Figure 6
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 (fig. 8)
•Connection, repairs, and wiring inspections may only be implemented by a company
(person) authorised 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 cable
with a switch that turns off all network poles and 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.
Ø10
Ø8

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Figure 7
2.5 OPERATION
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 8°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 pressurised connection water that increases its
volume due to heating must drip off the safety valve. In non-pressurised
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.

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Procedure of putting the heater into operation:
1. Check the water main and wiring. Check proper placement of operating and safety thermostat
sensors. The sensors must be inserted all the way in; first the operating and then the safety
thermostat.
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.
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.
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 on all poles. 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 jeopardised 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.

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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-pressurised connection this water drips off the
combination faucet valve). In full heating (about 74°C) the volumetric water gain is approx.
3.5 % 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 5.5 bars, a pressure control valve has to be fitted), or the safety
valve is defective. Please call a specialised plumber immediately!
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.

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2.9 MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES
FAILURE SYMPTOM INDICATOR SOLUTION
Water is cold
•Light on
•The temperature set on the thermostat is too low;
heating element failure
Water is cold
•Light off
•No supply voltage!
•Thermostat failure
•Safety thermostat shut off probably due to failed
operation thermostat
Water is not warm enough
•Light on
•Failure of one of the coils in the element (2x
1000W)
Temperature of water is not
corresponding with the
temperature set on the control
•Defective thermostat
Water is constantly dripping
off the safety valve
•
Light off
•
high input pressure
•defective safety valve
Table 4
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.
3OPERATION OF THERMOSTAT
3.1 OPERATING DEVICES OF THE HEATER
Electrical installation cover for heaters:
OKHE ONE 30, OKHE ONE 50, OKHE ONE 80, OKHE ONE 100, OKHE ONE 120
Figure 8
Thermostat button
Temeprature indicator

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Thermostat and no other part of the control panel is not a bearing part which can be used for
any handling with the heater.
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 9).
Figure 9
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.
4IMPORTANT NOTICES
4.1 INSTALLATION REGULATIONS
-Without a confirmation of performed electrical installation issued by an authorised 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.
„Optimum“ temper
ature (around 55°C)
Fixed mark on the
control panel
Temperature„anti-
freeze“ (around 8°C)
Lower limit of temperature
scope (around 5°C)
Upper temperature
scope limit o (around
80°C)

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-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 authorised service company.
-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 0.4 MPa.At the hot water
discharge we recommend that a reverse flap and an expansion tank are installed (at least 4% of hot
water volume in the manifold) to eliminate reverse pressure shocks.
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 water heater 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 heater packaging to a waste
disposal place determined by the municipality. When the operation terminates,
disassemble and transport the discarded and unserviceable heater to a waste
recycling centre (collecting yard), or contact the manufacturer.
5PRODUCT ACCESSORIES
The product is supplied together with a safety valve. The safety valves are packed and placed in the top
part of the heater package.
It is in your own interest to check the completeness of the accessories.
3-1-2018