Drazice OKH 100 NTR Specification sheet

OPERATION AND
INSTALLATION MANUAL
TANK TYPE INDIRECT WATER HEATERS
OKH 100 NTR/HV OKH 100 NTR
OKH 125 NTR/HV OKH 125 NTR
OKH 160 NTR
Družstevní závody Dražice - strojírna s.r.o.
Dražice 69, 294 71 Benátky nad Jizerou
tel.: +420 / 326 370 990
fax: +420 / 326 370 980
e-mail: [email protected]

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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
1.3 DESIGN AND GENERAL HEATER DIMENSIONS................................................................................... 5
2 OPERATION AND FITTING INSTRUCTIONS................................................................................................. 8
2.1 OPERATING CONDITIONS .................................................................................................................. 8
2.2 PLUMBING FIXTURE........................................................................................................................... 8
2.3 CONNECTION OF INDIRECT HEATER TO HOT WATER HEATING SYSTEM........................................ 10
2.4 FIRST HEATER COMMISSIONING ..................................................................................................... 11
2.5 PUTTING OUT OF SERVICE, DISCHARGE .......................................................................................... 11
2.6 INSPECTION, MAINTENANCE & CARE FOR THE APPLIANCE............................................................ 12
2.7 MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES .......................................................... 13
3 IMPORTANT NOTICES .............................................................................................................................. 13
3.1 INSTALLATION REGULATIONS.......................................................................................................... 13
3.2 PRODUCT ACCESSORIES .................................................................................................................. 14
3.3 DISPOSAL OF PACKAGING MATERIAL AND FUNCTIONLESS PRODUCT ........................................... 14

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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.
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 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.

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1PRODUCT TECHNICAL SPECIFICATION
1.1 FUNCTION DESCRIPTION
Indirect stationary heaters of NTR and NTR/HV series are used for hot service water preparation in
conjunction with another source of heating water, most often a gas boiler. Their nominal performance
provides sufficient amount of hot water for large flat units, premises, restaurants, and similar
establishments. In case of increased hot water consumption, these tanks heat water continuously,
operating similarly to flow heaters.
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.
1.2.2 ENERGY SAVING
Hot utility water reservoir is insulated by means of a 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.
Advantages of using indirect heater:
-easy installation and connection to hot water supply,
-very fast hot water heating system,
-enamelled steel tank ensures all hygienic requirements on the quality of hot utility
water,
-built-in Mg anode increases resistance to corrosion,
-good quality polyurethane insulation ensures minimum thermal losses,
-connection of multiple withdrawal points,
-accurate check of hot service water temperature,
-possibility of connecting hot service water circulation.

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1.3 DESIGN AND GENERAL HEATER DIMENSIONS
The heater receptacle is made of a steel plate and tested by 0.9 MPa overpressure. The inside of the
receptacle is enamelled. A flange is welded onto the upper bottom of the receptacle with a flange lid is
screwed to it. A sealing ring is inserted between the flange lid and the flange. Thermowells for thermostat
sensors and thermometer installation are placed in the flange lid. Anode rod is mounted on 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. Heat exchanger is welded in
the pressure tank.
Technical description: OKH 100 NTR, OKH 125 NTR, OKH 160 NTR
1 Thermometer
2 Enamelled steel receptacle
3 Heater shell
4 Polyurethane freon-free insulation
5 Tubular heat exchanger
6 Discharge outlet
7 Cold water filling pipe
8 Circulation
9 Mg anode
10 Hot water drain pipe
11 Electric installation cover
Figure 1
Technical desription: OKH 100 NTR/HV, OKH 125 NTR/HV
1 Thermometer
2 Enamelled steel receptacle
3 Heater shell
4 Polyurethane freon-free insulation
5 Tubular heat exchanger
6 Discharge outlet
7 Cold water filling pipe
8 Circulation
9 Mg anode
10 Hot water drain pipe
11 Electric installation cover
Figure 2

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OKH 100 NTR OKH 125 NTR OKH 160 NTR
A887 1052 1237
B* 882 1047 1232
C128 128 128
D516 516 516
E180 180 180
F621 750 750
L521 620 880
*Height from the bottom heater's edge to the end of the water inlet and outlet
tubes.
OKH 100 NTR/HV OKH 125 NTR/HV
A887 1052
B* 882 1047
C128 128
D516 516
E95 95
F141 141
G78 78
*Height from the bottom heater's edge to the end of the water inlet and outlet tubes.
Dimensions of heaters
OKH 100 NTR, OKH 125 NTR, OKH 160 NTR
Figure 3
OKH 100 NTR/HV, OKH 125 NTR/HV
Figure 4

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SPECIFICATIONS
Table 1
TYPE
OKH 100
NTR
OKH 125
NTR
OKH 160
NTR
OKH 100
NTR/HV
OKH 125
NTR/HV
VOLUME
l
95
120
160
95
120
MAX WEIGHT OF THE
HEATER WITHOUT
WATER
kg
57
71
78
56
70
HEAT TRANSFER
SURFACE
m2
1,08
1,45
1,45
1,08
1,45
MAX. TANK PRESSURE
MPa
0,6
MAX. PRESSURE OF
EXCHANGER
MPa
1
MAX. TEMPERATURE
OF HSW
°C
80
RECOMMENDED HSW
TEMPERATURE
°C
60
HSW CONNECTION
G ¾“
HEATING WATER
CONNECTION
G 1“
G 1“
G 1“
G ¾“
G ¾“
EL. PROTECTION
IP 44
RATED THERMAL
OUTPUT AT WATER
TEMPERATURE OF
80°c AND FLOW 720
l/h
W
24000
32000
32000
24000
32000
HEATING TIME FROM
10°C TO 60°C BY
EXCHAGER
min
14
14
17
14
14

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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 performance
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 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 the thermostat to be set to minimum operation
temperature of 60oC. 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 PLUMBING FIXTURE
Connecting heaters into water system in shown in Figure 5. For potential disconnection of
the heater, the service water inlets and outlets must be provided with screw coupling Js
3/4“.If the hot service water (HSW) distribution is equipped with circulation circuit, the
reverse pipe is connected to the inlet identified as CIRCULATION. The 100, 125, 160 NTR and
100, 125, 160 NTR / HV types are equipped with a discharge outlet. For operation, the
heater must be equipped with a safety valve. 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.
The safety valve must be easily accessible, as close to the heater as possible. The input pipes
must have at least the same clearance as the safety valve. The 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 - see
(Table 2). 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 the
assembly, follow the guide provided by the safety equipment manufacturer
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.

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Water can drip from the safety valve through the drain pipe; the pipe must be freely open to
the atmosphere, placed vertically and shall be in an environment free of temperatures below
freezing. When draining the heater, use a drain valve. You must first close the water supply
to the heater. Required pressures are in Table 2 below.. To ensure correct operation the
safety valve must be mounted on the inlet piping return valve, preventing spontaneous
heater draining and hot water penetrating back into the water main..
Required pressures - Table 2 - We recommend that the hot water distribution from the heater was as short
as possible to minimise heat losses.
Table 2
Connection of the heater exchanger (left, right) and fittings at the cold water inlet.
Figure 5
SAFETY VALVE STARTING
PRESSURE (MPa)
ADMISSIBLE OPERATING OVER-
PRESSURE OF WATER HEATER
(MPa)
MAXIMUM PRESSURE IN
COLD WATER PIPES
(MPa)
0,6
0,6
do 0,48
0,7
0,7
do 0,56
1
1
do 0,8
O –Air outlet valve
U –Shut-off valve
P1 –Safety valve with backflow flap
P2 –Safety valve for heating circuit
M –Manometer
Z –Test valve
V –Drain valve
Connection on the cold water inlet must conform to
national standard.

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2.3 CONNECTION OF INDIRECT HEATER TO HOT WATER HEATING
SYSTEM
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
The heating circuit is connected to marked inputs and outputs of the heater exchanger; the
deaerating valve is mounted in the highest place. It is necessary to install a filter into the
circuit in order to protect the pumps, the three-way valve, and backflow flaps, and the
exchanger from sedimentation. It is recommended to flush the heating circuit before the
assembly. All wiring connections must be properly insulated from heat. If the system works
with priority heating of HSW using a three-way valve, always follow the installation
instructions of the three-way valve’s manufacturer.
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.
Examples of connection of the heater to water and heating system
Figure 6

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2.4 FIRST HEATER 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.
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.
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 in
the thermo well have to be inserted all the way.
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
closes.
5. In case of a leakage (flange lid), we recommend fastening the flange lid bolts.
6. Fasten the electric installation cover.
7. When heating service water with electric energy from the hot water heating system, open the
heating water inlet and outlet valves, possibly de-aerate the heat 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.
2.5 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.
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- only if an external thermostat is connected.
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. 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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2.6 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. Repetitive water heating causes limestone
sediment on both the tank walls and chiefly the flange lid. The sedimentation depends on
the hardness of water heated, its temperature, and amount of hot water consumed.
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. Have the company in charge of service affairs clean and exchange the anode.
When discharging water from the heater, the combination faucet valve for hot water must
be open in order to avoid creating under pressure that would prevent water discharge. This
has to be performed after one or two years of operation. The cleaning is carried out through
the hole in the flange by: draining the boiler, dismantling the flange lid and cleaning the tank.
A new sealing has to be used for re-fitting. Since the inside of the heater has special enamel,
the surface of which must not get in contact with a 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 or
dye thinners to clean the outer shell of the heater (such as cellulose thinner, trichlor, and the
like). For cleaning use a wet clout and add a few drops of liquid cleaning agent for household
applications.

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2.7 MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES
FAILURE SYMPTOM
LED
SOLUTION
Water is constantly
dripping off the safety
valve
LED is not on
input pressure is too high
faulty safety valve
Table 3
Do not try 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.
3IMPORTANT NOTICES
3.1 INSTALLATION REGULATIONS
-Check and exchange the Mg anode regularly.
-No stop valves can be put between the heater and the safety valve.
-If the overpressure in the eater main exceeds 0.6 MPa, a reduction valve must be mounted
before the safety valve.
-All outlets of hot water must be equipped with 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.
-It is not allowed to handle the thermostat, aside from temperature resetting with a control
button.
-All electric installation handling, setting, and regulation feature exchange, may only be
implemented by a service company.
Both the electric and water installation must follow and meet the requirements and
regulations relevant in the country of use!
Please note that the heater can't be switched on at the mains when working in the vicinity
of flammable liquids (petrol, spot remover) or gases, etc..

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3.2 PRODUCT ACCESSORIES
G3/4" safety valve is packed with the product and the OKC 100, 125 NTR and OKC 100, 125, 160 NTR/ HV
types are additionally equipped with a discharge valve.
It is in your own interest to check the completeness of the accessories.
3.3 DISPOSAL OF PACKAGING MATERIAL AND FUNCTIONLESS
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
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 centre (collecting yard), or contact
the manufacturer.
6-2015