Dražice OKC 100 NTR Specification sheet

OPERATION AND
INSTALLATION MANUAL
TANK TYPE INDIRECT WATER HEATERS
OKC 80 NTR/Z
OKC 100 NTR OKC 100 NTR/HV OKC 100 NTR/Z
OKC 125 NTR OKC 125 NTR/HV OKC 125 NTR/Z OKCV 125 NTR
OKC 160 NTR OKC 160 NTR/HV OKC 160 NTR/Z OKCV 160 NTR
OKCV 180 NTR
OKC 200 NTR OKC 200 NTR/Z OKCV 200 NTR
OKC 250 NTR
OKC 200 NTRR
OKC 250 NTRR
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
1TECHNICAL SPECIFICATION OF PRODUCT .................................................................................................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 ....................................................................................... 5
1.3 DESIGN AND GENERAL HEATER DIMENSIONS................................................................................... 6
2OPERATION AND FITTING INSTRUCTIONS............................................................................................... 17
2.1 OPERATING CONDITIONS ................................................................................................................ 17
2.2 WALL MOUNTING............................................................................................................................ 17
2.3 PLUMBING FIXTURE......................................................................................................................... 18
2.4 ELECTRIC WIRING ............................................................................................................................ 22
2.4.1 ELECTRIC INSTALLATION GENERAL INFORMATION.................................................................22
2.4.2 METHODS OF ELECTRONIC THERMOSTAT CONNECTION ....................................................... 22
2.5 CONNECTION OF INDIRECT HEATER TO HOT WATER HEATING SYSTEM ........................................ 23
2.6 FIRST HEATER COMMISSIONING ..................................................................................................... 23
2.7 PUTTING OUT OF SERVICE, DISCHARGE .......................................................................................... 24
2.8 INSPECTION, MAINTENANCE & CARE FOR THE APPLIANCE ............................................................ 25
2.9 MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES .......................................................... 26
3. OPERATION OF THERMOSTAT................................................................................................................. 26
3.1 OPERATING MODES......................................................................................................................... 26
3.1.1 SERVICING................................................................................................................................ 26
3.1.2 TEMPEATURE SETTING ............................................................................................................ 27
3.1.3 LIMITING THE REGULATION RANGE; LOCKED SETTINGS......................................................... 27
4IMPORTANT NOTICES .............................................................................................................................. 28
4.1 INSTALLATION REGULATIONS.......................................................................................................... 28
4.2 DISPOSAL OF PACKAGING MATERIAL AND FUNCTIONLESS PRODUCT ........................................... 29
5 PRODUCT ACCESSORIES............................................................................................................................... 29

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Meaning of pictograms used in Manual
Important information for heater users.
Recommendations of manufacturer, observance of which will ensure trouble-free
operation and long service life of the product.
CAUTION!
Important notice to be observed.
READ CAREFULLY THE BELOW INSTRUCTIONS PRIOR TO THE INSTALLATION THE
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%.
Product’s reliability and safety is proven by tests implemented by the Engineering Test Institute in Brno.

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1TECHNICAL SPECIFICATION OF PRODUCT
1.1 FUNCTION DESCRIPTION
Indirect stationary heaters of NTR and NTRR series are used for HSW water heating in conjunction with
another source of heating water, most often a gas boiler, for NTRR types combination of two heating water
sources (gas boiler + solar system, heat pump). Their nominal performance provides sufficient amount of
hot service water (HSW) even 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.
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 1, Figure 2, Figure 3, Figure 4). The time of heating using the heat exchanger
depends on the temperature and flow of water in the hot water heating system. Combined heater is made
in universal design – depending on the need of connecting the closing valves to the heating element from
the right or left.
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 th
e
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
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.
Hot utility water reservoir is insulated by means of a first-class polyurethane foam with zero
Freon 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 heat exchanger.

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Advantages of using indirect heater
−Easy installation and connection to heating water supply,
−very fast HSW heating,
−enamelled steel tank ensures all hygienic requirements on the quality of HSW,
−built-in Mg anode increases resistance to corrosion,
−good quality polyurethane insulation ensures minimum thermal losses,
−continuously adjustable temperature of HSW up to 74°C,
−connection of multiple withdrawal points,
−the type with two heat exchangers can use two heating water supplies, or double heat
transfer surface can be obtained if those are combined,
−heater operation control light,
−accurate check of HSW temperature,
−possibility of connecting HSW circulation.
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 [kWh/24h] and indicates the amount of
power needed to maintain the set temperature. Data Sheet pursuant to Directive No - see
Table 1.
TYPE
HEATING
WATER FLOW
(l/h)
PRESSURE
LOSS (mbar)
HEAT LOSSES
kW/24h
OKC 100 NTR
720
33
OKC 125 NTR
OKC 160 NTR
46
OKC 200 NTR
OKC 250 NTR
2 x 33
OKC 200 NTRR
OKC 250 NTRR
61
Table 1

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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 lower bottom of the receptacle with a flange lid
screwed onto it. A sealing ring is inserted between the flange lid and the flange. Thermo wells 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(s)
is/are welded onto the pressure tank.
Description of basic parts of the heater – Figure 1, Figure 2, Figure 3, Figure 4. Heater dimensions – (Figure
5, Figure 6, Figure 7, Figure 8) and (Table 2, Table 4, Table 6, Table 8)
Technical description: OKC 100 NTR, OKC 125 NTR, OKC 160 NTR, OKC 200 NTR, OKC 250 NTR, OKC 200
NTRR, OKC 250 NTRR
Figure 1

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Technical description: OKC 100 NTR/HV, OKC 125 NTR/HV, OKC 160 NTR/HV
Figure 2
Technical description: OKC 80 NTR/Z, OKC 100 NTR/Z, OKC 125 NTR/Z, OKC 160 NTR/Z,
OKC 200 NTR/Z
Figure 3

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Technical description: OKCV125 NTR, OKCV 160 NTR, OKCV 180 NTR, OKCV 200 NTR
Figure 4

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OKC 100 NTR, OKC 125 NTR, OKC 160 NTR OKC 200 NTR, OKC 250 NTR, OKC 200 NTRR, OKC 250 NTRR
Figure 5Figure 6
TYPE
OKC 100
NTR
OKC 125
NTR
OKC 160
NTR
OKC 200
NTR
OKC 200
NTRR
OKC 250
NTR
OKC 250
NTRR
A
881
1046
1235
1400
1400
1580
1580
B*
876*
1041*
1230*
1280
1280
1460
1460
C
621
751
751
-
1150
-
1330
D
521
621
881
-
-
-
-
E
-
-
-
950
950
1060
1060
F
-
-
-
-
710
-
890
G
-
-
-
780
650
780
650
* Height from the bottom heater’s edge to the end of the water inlet and outle.
Table 2

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TYPE
OKC 100
NTR
OKC 125
NTR
OKC 160
NTR
OKC 200
NTR
OKC 200
NTRR
OKC 250
NTR
OKC 250
NTRR
CAPACITY
l
95
115
145
210
200
250
245
MAX. OPERATING
OVERPRESSURE IN
THE TANK
MPa
0,6
MAX. OPERATING
PRESSURE IN THE
EXCHANGER
MPa
1
ELECTRIC
CONNECTION OF
CONTROL
ELEMENTS
1 PE-N 230 V/50Hz
EL. PROTECTION
IP 44
MAX.
TEMPERATURE OF
HSW
°C
80
RECOMMENDED
HSW
TEMPERATURE
°C
60
MAX. WEIGHT OF
THE HEATER
WITHOUT HEATER
kg
57
69
77
95
108
107
118
EXCHANGER HEAT
SURFACE
m2
1.08
1.45
1.45
1.45
2 x 1.08
1.45
2x 1.08
RATED THERMAL
OUTPUT AT
HEATING WATER
TEMPERATURE OF
80°C AND FLOW
720 l/h
W
24000
32000
32000
32000
2 x
24000
32000
2 x 24000
TIME OF HEATING
BY EXCHANGER
FROM 10°C TO
60°C
min
14
14
17
22
28 / 16
28
36 / 20
HEAT LOSSES
kWh/
24h
Table 3

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OKC 100 NTR/HV, OKC125 NTR/HV, OKC160 NTR/HV
Figure 7
The height from the bottom edge of the heater to the end of the pipe inlet and outlet.
Table 4
TYP
OKC 100 NTR/HV
OKC 125 NTR/HV
OKC 160 NTR/HV
A
881
1046
1087
B*
876
1041
1082
C
124
124
146
D
524
524
584
E
95
95
134
F
142
142
174
G
78
78
110

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TYPE
OKC 100
NTR/HV
OKC 125
NTR/HV
OKC 160
NTR/HV
CAPACITY
l
95
120
155
MAX. OPERATING OVERPRESSURE IN
THE TANK MPa 0,6
MAX. OPERATING OVERPRESSURE IN
THE EXCHANGER MPa 1
ELECTRIC CONNECTION OF CONTROL
ELEMENTRS 1 PE-N 230V/50Hz
IP PROTECTION
IP 44
MAX. HOT WATER TEMPERATURE
°C
80
RECOMMENDED HSW TEMPERATURE °C 60
MAX. WEIGHT OF THE HEATER
WITHOUT WATER kg 56 70 78
EXCHANGER HEAT SURFACE
m2
1.08
1.45
1.45
RATED THERMAL OUTPUT AT HEATING
WATER TEMPERATURE OF 80°C AND
FLOW 720 l/h W 24000 32000 32000
TIME OF HEATING BY EXCHANGER
FROM 10°C TO 60°C min 14 14 17
HEAT LOSSES
kWh/24h
Table 5

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OKC 80 NTR/Z, OKC 100 NTR/Z, OKC 125 NTR/Z, OKC 160 NTR/Z, OKC 200 NTR/Z
Figure 8
Table 6
Type
OKC 80
NTR/Z
OKC 100
NTR/Z
OKC 125
NTR/Z
OKC 160
NTR/Z
OKC 200
NTR/Z
A
736
881
1046
1235
1287
B*
731
876
1041
1230
1282
C
615
636
801
1005
793
D
524
524
524
524
584
E
501
701
701
701
685
F
-
551
551
831
895
G
3/4"
1"
1"
1"
1"
H
-
3/4"
3/4"
3/4"
3/4"
I
211
261
261
261
245
J
-
-
-
815
600
Upper and lower
Hinge 160,180, 200L
4 anchor bolts
Dimensions 450mm and J
Check before drilling
Upper hinge and
support
50-125L
2 anchor bolt

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TYPE
OKC 80
NTR/Z
OKC 100
NTR/Z
OKC 125
NTR/Z
OKC 160
NTR/Z
OKC 200
NTR/Z
CAPACITY
l
80
100
125
155
195
MAX. OPERATING OVERPRESSURE IN
THE TANK MPa 0,6
MAX. OPERATING PRESSURE IN THE
EXCHANGER MPa 1
ELECTRIC CONNECTION OF CONTROL
ELEMENTS 1 PE-N 230V/50Hz
EL. PROTECTION
IP 45
MAX. TEMPERATURE OF HSW
°C
80
RECOMMENDED HSW TEMPERATURE
°C
60
HEIGHT OF THE HEATER
mm
736
881
1046
1235
1287
DIAMETER OF THE HEATER
mm
524
524
524
524
584
MAX. WEIGHT OF THE HEATER
WITHOUT HEATER kg 39 56 62 70 87
EXCHANGER HEAT SURFACE
m2
0.41
1.08
1.08
1.08
1.08
RATED THERMAL OUTPUT AT
HEATING WATER TEMPERATURE OF
80°C AND FLOW 720 l/h W 9000 24000 24000 24000 24000
TIME OF HEATING BY EXCHANGER
FROM 10°C TO 60°C min 32 14 17 23 28
HEAT LOSSES
kWh/
24h
Table 7

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OKCV 125 NTR, OKCV 160 NTR, OKCV 180 NTR, OKCV 200 NTR
Figure 9
TYPE
OKCV 125 NTR
OKCV 160 NTR
OKCV 180 NTR
OKCV 200 NTR
A
1046
1235
1187
1287
B
600
700
600
600
C
908
1008
907
907
D
524
524
584
584
E
184
230
258
255
F
513
650
570
670
G
200
200
240
240
H
559
559
616
616
I
350
350
358
362
J
225
225
252
252
Table 8

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TYPE
OKCV
125 NTR
OKC 160
NTR
OKCV
180 NTR
OKCV
200 NTR
CAPACITY
l
125
152
180
200
MAX. OPERATING OVERPRESSURE IN
THE TANK MPa 0,6
MAX. OPERATING PRESSURE IN THE
EXCHANGER MPa 0,4
ELECTRIC CONNECTION OF CONTROL
ELEMENTS 1 PE-N 230 V/50Hz
EL. PROTECTION
IP 44
MAX. TEMPERATURE OF HSW
°C
80
RECOMMENDED HSW TEMPERATURE
°C
60
MAX. WEIGHT OF THE HEATER
WITHOUT HEATER kg 55 65 76 80
EXCHANGER HEAT SURFACE
m2
0.7
0.7
0.75
0.75
RATED THERMAL OUTPUT AT HEATING
WATER TEMPERATURE OF 80°C AND
FLOW 720 l/h
W 15000 16800 18000 18000
TIME OF HEATING BY EXCHANGER
FROM 10°C TO 60°C min 37 35 38 43
RATED THERMAL OUTPUT AT HEATING
WATER TEMPERATURE OF 80°C AND
FLOW 310 l/h
W 8000 10260 11000 11000
TIME OF HEATING BY EXCHANGER
FROM 10°C TO 60°C min 70 60 63 72
HEAT LOSSES
kWh/24h
Table 9

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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.
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 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 WALL MOUNTING
Prior to mounting, check the loading capacity of the wall and, depending on the type of
masonry, choose a suitable anchorage material, or reinforce the wall, if needed. The NTR/Z
series water heater shall only be mounted in vertical position so that the lower edge of the
heater was placed at least 600 mm above the floor. The OKCV NTR series water heater shall
only be mounted in horizontal position so that, from the front view, the right edge of the
heater was placed at least 600 mm from the opposite wall. In combined heaters, elbows
have to be attached to the heating water inlet and outlet and, by turning them, determined
the mounting either from the right or from the left (Figure 10). With regard to various types
of carrying masonry and broad assortment of special anchorage material available at the
market, we do not provide heaters with this material. The anchorage system has to be
selected individually, depending on the conditions. We recommend an authorised company
perform mounting on the wall and anchorage, or discuss the anchorage with a professional.
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.

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Figure 10
2.3 PLUMBING FIXTURE
For potential disconnection of the heater, the service water inlets and outlets must be
provided with screw coupling Js 3/4“ (Figure 11, Figure 12, Figure 13). 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. In 200 and 250 NTR(R) types, the HSW inlet has to be
provided with a “T” fixture with a drain valve. 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 10. If the water main pressure exceeds such value, a reduction valve must be

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Required pressures – Table 10.We recommend that the hot water distribution from the heater was as
short as possible to minimise heat losses.
Table 10
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.
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.
SAFETY VALVE
STARTING
PRESSURE
[MPa]
ADMISSIBLE
OPERATING
OVER-
PRESSURE 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
do 0.8

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Figure 11
Figure 12
0 - 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