Drazice OKC 100 NTR/HV Specification sheet

OPERATING AND
INSTALLATION MANUAL
COMBINED WATER HEATERS AND TANKS
FOR VERTICAL ASSEMBLY
Tank-type water heaters
OKC 80 OKC 160
OKC 100 OKC 200
OKC 125
Hot water tanks
OKC 100/1 m2OKC 160/1 m2
OKC 125/1 m2OKC 200/1 m2
Družstevní závody Dražice-strojírna s.r.o.
(Works Cooperative - Dražice - Machine Plant, Ltd.)
Dražice 69, 294 71 Benátky nad Jizerou
tel.: +420 / 326 370 911
fax: +420 / 326 370 980
e-mail: expo[email protected]z

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CONTENTS
1PRODUCT TECHNICAL SPECIFICATION....................................................................................................... 3
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................................................................................... 5
2OPERATION AND FITTING INSTRUCTIONS............................................................................................... 11
2.1 OPERATING CONDITIONS ................................................................................................................ 11
2.2 WALL MOUNTING............................................................................................................................ 11
2.3 PLUMBING FIXTURE......................................................................................................................... 13
2.4 ELECTRICAL INSTALLATION.............................................................................................................. 15
2.4.1 GENERAL INFORMATION FOR ELECTRICAL INSTALLATION ..................................................... 15
2.5 OPERATION...................................................................................................................................... 16
2.6 FIRST COMMISSIONING................................................................................................................... 16
2.7 PUTTING OUT OF SERVICE, DISCHARGE .......................................................................................... 17
2.8 INSPECTION, MAINTENANCE & CARE FOR THE APPLIANCE............................................................ 18
2.9 MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES .......................................................... 18
3OPERATION OF THERMOSTAT................................................................................................................. 20
3.1 SERVICING........................................................................................................................................ 20
3.1.1 OPERATING DEVICES OF THE HEATER ..................................................................................... 20
3.1.2 TEMPERATURE SETTING .......................................................................................................... 21
4IMPORTANT NOTICES .............................................................................................................................. 22
4.1 INSTALLATION REGULATIONS.......................................................................................................... 22
4.2 TRANSPORT & STORAGE INSTRUCTIONS ........................................................................................ 22
4.3 DISPOSAL OF PACKAGING MATERIAL AND NON-FUNCTIONING PRODUCT.................................... 23
5 PRODUCT ACCESSORIES .......................................................................................................................... 23

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CAREFULLY READ THIS MANUAL BEFORE INSTALLING THE WATER HEATER!
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.
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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1PRODUCT TECHNICAL SPECIFICATION
1.1 FUNCTION DESCRIPTION
The heater is designed for the so-called accumulation heating of service water by electric energy,
or by thermal energy through exchanger. Water is heated by an electric element at a time determined
by the electricity supplier, or by a heat exchanger in an enamelled thermally insulated tank. At the time
of the heating, the element is controlled by thermostat on which the desired temperature can be set (ranging
from 5 and 74°C). Once the selected temperature is reached, heating interrupts automatically. Water
accumulated in the tank is then used for the 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. The 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
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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TANK HEATER
TYPES NOMINAL CAPACITY [L] HEATING TIME FROM 10°C TO 60°C [hours]
ELECTRICITY
CONSUMPTION FOR
HEATING OF VOLUME
FROM 15°C TO 65°C [kWh]
OKC 80 75 2.04.8
OKC 100;
OKC 100/1 m295 2.5 6
OKC 125;
OKC 125/1 m2120 3.28
OKC 160;
OKC 160/1 m2147 3.99.6
OKC 200;
OKC 200/1 m2195 5.212
Table 1
1.3 DESIGN AND GENERAL HEATER DIMENSIONS
The heater tanks are made of a steel plate and tested by 1.5 MPa multiple of operation pressure value.
The inside of the tank is enamelled. 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 and sensors of regulation thermostat and safety fuse are located in the flange lid. An anode rod
is mounted onto the M8 nut. The water reservoir is insulated by means of polyurethane foam. Electric
wiring is placed underneath the plastic removable cover. The temperature of water can be set using
the thermostat. In combined versions, a heat exchanger is welded in the pressure tank. The heat exchanger
is only intended for the heating circuit.

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OKC 80, OKC 100, OKC 125
Upper suspension + detent support (rectifying screw)
Figure 1
OKC 160
Upper suspension + lower suspension
Figure 2
3/4" outer
3/4" outer

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OKC 200
Upper suspension + lower suspension
Figure 3
OKC 100/1m2, OKC 125/1m2
Upper suspension + detent support (rectifying screw)
Figure 4
3/4" outer

3/4" outer

1" outer

3/4" inner

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OKC 160/1m2
Upper suspension + lower suspension
Figure 5
OKC 200/1m2
Upper suspension + lower suspension
Figure 6

3/4" outer

1" outer

3/4" inner

3/4" outer

1" outer

3/4" inner

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* Check the R dimensions before drilling.
The values behind the slash apply to heaters with a 1 m2exchanger.
Table 2
TYPE OKC 80 OKC 100
OKC 100/1m2
OKC 125
OKC 125/1m2
OKC 160
OKC 160/1m2
OKC 200
OKC 200/1m2
A 757 902 1067 1255 1290
B 612 612 612 612 655
C 70 70 70 70 70
D 524 524 524 524 584
E 605 755/622 755/789 995/991 790/784
F 460 610/478 610/645 720/815 600
G - -/550 -/550 -/830 -/889
H 142 137/270 302/268 250/254 490/496
I 211 211/263 211/263 211/263 239
J 501 651/703 651/703 651/703 679
K 172 172 172 172 172
R 450 450 450 450 450

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Table 3
TYPE OKC 80
OKC 100
OKC 100/1 m2
OKC 125
OKC 125/1 m2
OKC 160
OKC 160/1 m2
OKC 200
OKC 200/1 m2
VOLUME L 75 95 120 147 195
MAX OPERATING
OVERPRESSURE IN THE TANK MPa 0.6
MAX MAXIMUM OPERATING
OVERPRESSURE IN THE
EXCHANGER*
MPa 1
ELECTRICAL CONNECTION V 1 PE-N ~ 230V/50Hz
INPUT W 2200
EL. PROTECTION
IP 44
MAX TEMPERATURE OF HOT
WATER °C 80
MAX OPERATING
TEMPERATURE IN THE
EXCHANGER
°C 110
RECOMMENDED
TEMPERATURE OF HOT WATER °C 60
HEIGHT OF THE HEATER mm 757 902 1067 1255 1290
DIAMETER OF THE HEATER mm 524 524 524 524 584
MAX WEIGHT OF THE HEATER
WITHOUT WATER kg 40 50/57 55/64 62/71 79/85
TIME OF EL. HEATING FROM
10°C TO 60°C* hrs 2.0 2.5 3.2 3.9 5.2
TYPE
OKC 80
OKC 100
OKC 125
OKC 160
OKC 200
EXCHANGER HEAT TRANSFER
SURFACE m20.41 0.68 0.68 0.68 0.68
HEATING TIME BY EXCHANGER
FROM 10°C TO 60°C AT FLOW
720 l/h
min 32 23 28 35 45
RATED THERMAL OUTPUT AT
HEATING WATER
TEMPERATURE 80°C AND
FLOW 310 l/h
W 6000 9000 9000 9000 9000
HEATING TIME BY EXCHANGER
FROM 10°C TO 60°C AT FLOW
310 l/h
min 50 48 55 67 86
LOAD PROFILE M M M L XL
DAILY ELECTRICITY
CONSUMPTION kWh 6.19 6.31 6.59 12.03 20.34
MIXED WATER V40 L 138.7 165.41 231.1 242.83 331.26
TYPE
OKC 100/1m
2
OKC 125/1m
2
OKC 160/1m
2
OKC 200/1m
2
EXCHANGER HEAT TRANSFER
SURFACE m2- 1.08 1.08 1.08 1.08
RATED OUTPUT AT HEATING
WATER TEMPERATURE OF
80°C AND FLOW 720 L/H
W - 24000 24000 24000 24000
HEATING TIME BY EXCHANGER
FROM 10°C TO 60°C min - 14 17 21 28
STATIC LOSS W - 47 57 67 72

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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 room, in which the appliance will be operated, must be frost-free. The temperature
in the heater installation location must not exceed +2 °C. The appliance has to be mounted
at a convenient place; it means that the appliance must be easily accessible for potential
necessary maintenance, repair or replacement, as the case may be.
We would like to emphasise that the heater must not be connected to power supply if work
involving flammable liquids (petrol, spot remover) or gases, etc., is performed nearby.
If water is strongly calcareous we recommend that any of the common decalcifying device
was installed with the appliance, or the thermostat to be set to the minimum operation
temperature of 60°C (setting to position „ECO“ or „OPTIMUM“) - Figure 15, Figure 16.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 the bolts for suspending
the heater is 12 mm. When mounting the anchor bolts follow the manual provided by the
anchor bolts' manufacturer.
Mount the anchors by the dimensional drawing (Figure 1to Figure 6) in a 450 mm spacing. 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 (Figure 7) inthe 80 - 125 L heaters.
Figure 7

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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. Free
space of up to 500 mm from the bottom edge of the heater has to be available under the heater.
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.
Figure 8

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2.3 PLUMBING FIXTURE
The heater connects to water distribution tubes with G1/2“ 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 1/2“.
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 9).
The safety valve with a check valve is supplied with the heater.
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.
Table 4
SAFETY VALVE STARTING
PRESSURE [MPa]
ACCEPTABLE OPERATING
OVER-PRESSURE OF THE
WATER HEATER [MPa]
MAX COLD WATER
PRESSURE IN PIPING [MPa]
0.6 0.6 up to 0.48
0.7 0.7 up to 0.56
11up to 0.8

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It is recommended to install stop valves on
the heating water inlet and outlet (for
possible dismantling of the heater). The
valves have to be as close to the heater as
possible to avoid higher thermal losses.
Figure 9
Figure 10

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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 12).
In the electric wiring casing remove the partition corresponding with the input wire diameter of Ø8 or Ø10
(Figure 11). The degree of protection of electric parts of the heater is IP 44. Power input of electric element
is 2200 W.
Figure 11
It is necessary to observe the below requirements during the electric wiring.
•The wiring diagram is attached to the heater on the electrical installation guard (see
Figure 12).
•The electrical installation shall only be connected, repaired and inspected by a person
authorised to perform that activity.
•Expert connection must be confirmed on the warranty certificate.
•The heater is connected to the 230 V/50 Hz electricity supply using a fixed moving conductor
with a switch that turns off all network poles and the circuit breaker (protector).
•In the OKC 80 - 125 and OKC 100 - 125/1m2heaters, after wall mounting and adjusting
the distance from the wall by M8x80 rectifying screw, connect the external protective
connection wire to the rectifying screw.
•In the OKC 160 - 200 and OKC 160 - 200/1m2heaters, after wall mounting, connect
the external protective connection wire to the bottom hinge to the earth screw.
•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
Ø8
Ø10

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Figure 12
2.5 OPERATION
a) Water heating by electric energy
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. In combined versions,
the stop valve on the inlet to the exchanger has to be closed at the inlet to the heat exchanger while which
prevents heating the water in the hot water heating system.
b) Service water heating via thermal energy through heat exchanger
Closing valves of the heat exchanger must be opened which ensures heating water flow from the hot water
heating system. Together with the closing valve, it is recommended to install an air outlet valve at the inlet
to the heat exchanger in order to bleed the heat exchanger as needed, in particular before the beginning
of the heating season (Figure 9). The time it takes to heat up using the heat exchanger depends
on the temperature and flow of water in the hot water heating system. A combined heater is made
in universal design - depending on the need of connecting the closing valves to the heating element either
from the right, or from the left.
2.6 FIRST COMMISSIONING
After connecting the heater to the water supply, the hot water heating system, the electric
network, and after testing its safety valve (based on the valve manual attached), the heater may
be put into operation. 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.

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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 must be more-or-less the same. 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.
Procedure of putting the heater into operation
1. Check both water and electric installation; for combined heaters, check also the installation
to the hot water heating system. Check proper placement of thermostat sensors. The sensors must
be inserted all the way in; first the thermostat and then the safety fuse.
2. Open the hot water valve on the combination faucet.
3. Open the cold water inlet valve to the heater.
4. Once water starts draining through the combination faucet valve for hot water, the filling
of the heater is completed 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 heating utility water with heat energy from the hot water heating system, open the heating
water inlet and outlet valves, or de-aerate the exchanger.
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 utility 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. 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 drip off
the safety valve outlet (in non-pressurised connection this water drips off the combination
faucet valve). In full heating (about 65oC) the volumetric water gain is approx. 3% of the tank
capacity. The function of the safety valve has to be checked regularly (based on the information
contained in the attached safety valve manual). In common operation, such a check needs to be
implemented at least once a month, and after each heater shutdown that exceeds 5 days.
Caution! 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 pressure in the supply piping is either too high,
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
•Light off
•The temperature set on the thermostat
is too low
•Heating element failure
•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
(contains 2)
Temperature of water
is not corresponding
with the set value
•Defective thermostat
Water is constantly
dripping off the safety
valve
•Light off •high input pressure
•defective safety valve
Table 5
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.

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3OPERATION OF THERMOSTAT
3.1 SERVICING
3.1.1 OPERATING DEVICES OF THE HEATER
Electric installation cover for heaters OKC 200, OKC 200/1m2
Figure 13
Electric installation cover for heaters OKC 80, OKC 100, OKC 125, OKC 160,
OKC 100/1m2, OKC 125/1m2,OKC 160/1m2
Figure 14
Thermostat and no other part of the control panel is not a bearing part which can be used
for any handling with the heater.
Tipping plastic guard
Electric circuit closing indicator lamp
Thermostat knob
Thermostat knob
Electric circuit closing indicator lamp