Drazice OKC 500 NTR/HP Specification sheet

OPERATING and
INSTALLATION MANUAL
INDIRECT WATER HEATER
OKC 250 NTR/HP
OKC 300 NTR/HP
OKC 400 NTR/HP
OKC 500 NTR/HP
OKC 750 NTR/HP
OKC 1000 NTR/HP
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: [e-mail]

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CONTENTS
1TECHNICAL SPECIFICATION OF PRODUCT.................................................................................................4
1.1 FUNCTION DESCRIPTION ..................................................................................................................4
1.2 DESIGN AND GENERAL HEATER DIMENSIONS ..................................................................................4
1.2.1 PRODUCT DESCRIPTION............................................................................................................4
1.2.2 TECHNICAL DATA ......................................................................................................................5
2OPERATION AND FITTING INSTRUCTIONS ..............................................................................................12
2.1 PUTTING THE HEATER INTO OPERATION........................................................................................12
2.2 CONNECTING A HEATER TO A HOT WATER DISTRIBUTION ............................................................12
2.3 PLUMBING FIXTURE........................................................................................................................13
2.4 CONNECTING A HEATER TO A HEATING SYSTEM............................................................................14
2.5 HEATER CLEANING AND ANODE ROD EXCHANGE ..........................................................................15
2.6 SPARE PARTS ..................................................................................................................................15
3 IMPORTANT NOTICES .............................................................................................................................15
3.1 IMPORTANT NOTICES .....................................................................................................................15
3.2 INSTALLATION REGULATIONS.........................................................................................................16
3.3 DISPOSAL OF PACKAGING MATERIAL AND FUNCTIONLESS PRODUCT............................................16

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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 heater OKC 250 (300, 400, 500, 750, 1000) NTR / HP is designed for water heating in
conjunction with a heat pump. Reheat can be carried out by the electric heater TJ 6 / 4“.
1.2 DESIGN AND GENERAL HEATER DIMENSIONS
1.2.1 PRODUCT DESCRIPTION
The heater vessel is welded from a steel plate and as a whole is protected by enamel resistant to hot water.
Magnesium anode is added in the vessel as an additional protection against corrosion, which regulates the
electric potential of the inside of the vessel and thus reduces the effects of corrosion. Inside the vessel
there is a welded heat exchanger made of steel pipe with enamelled outer coating, and connections of hot
and cold water, circulation and thermostat tank.
The pipe heat exchanger is only intended for the heating circuit.
On the side of the heater there is a cleaning and inspection aperture ending with a flange of 110 mm
diameter, the pitch of eight M8 bolts is 150 mm. The heater is equipped with a G 1 ½ " aperture for
screwing an additional heater. This option is used, if the heater is connected into the system with a heat
pump, for water reheating at the top of the heater to the desired temperature. The tank is insulated by 50
or 60 mm of polyurethane foam not containing CFCs and the casing of the heater is made of plastic.

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1.2.2 TECHNICAL DATA
Table 1
Typ
OKC 250
NTR/HP
OKC 300
NTR/HP
OKC 400
NTR/HP
OKC 500
NTR/HP
OKC 750
NTR/HP
OKC 1000
NTR/HP
Capacity
l
245
295
356
440
727
945
Height
mm
1541
1580
1591
1921
2050
2083
Diameter
mm
584
670
700
700
990
1090
Maximum weight without
water
kg
119
138
172
203
263
335
Maximum operating
pressure in the tank
MPa
1
1
1
1
1
1
Maximum operating
overpressure in the
exchanger
MPa
1
1
1
1
1
1
Maximum heating water
temperature
°C
110
110
110
110
110
110
Maximum temperature of
HSW (Hot Service Water)
°C
90
90
90
90
90
90
Exchanger heat surface
m2
2,5
3,2
5
6,2
7,0
9,0
Exchanger volume
l
16
24
35
43
49
64

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OKC 250 NTR/HP
Figure 1

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OKC 300 NTR/HP
Figure 2

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OKC 400-500 NTR/HP
Figure 3

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OKC 750 NTR/HP
Figure 4

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OKC 1000 NTR/HP
Figure 5

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2OPERATION AND FITTING INSTRUCTIONS
2.1 PUTTING THE HEATER INTO OPERATION
After connecting the heater to the water distribution system, hot water heating system, respectively
electrical power system and after checking the safety valve (following the instructions attached to the
valve) the heater can be put into operation.
Procedure:
a) Check the plumbing and electrical installation, including the connection to hot-water heating system.
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.
b) Open the hot water valve on the combination faucet;
c) Open the cold water inlet valve to the heater.
d) When the water starts to flow through the hot water valve, the filling of the heater is finished and the
valve needs to be closed.
e) Should a leak (of the flange lid) occur, we recommend tightening the screws of the flange lid.
f) When heating the water with thermal energy from hot water heating system, turn off the electricity
and open the valves at the inlet and outlet of heating water or bleed the exchanger. When commencing
operation, flush the heater until the cloudiness in the water is gone.
g) Make sure to fill in properly the warranty certificate.
2.2 CONNECTING A HEATER TO A HOT WATER DISTRIBUTION
Figure 6

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The heater’s cold water inlet must be fitted with a T-fitting with a discharge valve for any
discharge of water from the heater
Each individually lockable heater must also be equipped at the hot water inlet with a test
cock, check valve, safety valve and level gauge.
2.3 PLUMBING FIXTURE
Power water connects to pipes with 3/4”thread in the bottom part of the heater. Blue - cold
water supply, red –hot water outlet. For potential disconnection of the heater, the service
water inlets and outlets must be provided with screw coupling Js 3/4”. Safety valve is
mounted on the cold water inlet identified with a blue ring.
Each hot service water pressure heater must have a membrane spring loaded with a safety
valve. Nominal clearance of safety valves is defined in the Standard. The heaters are not
equipped with a safety valve. 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 (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 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 manually moving of the membrane from the seat, turning the make-and-break
device button always to the right. 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.
When draining the heater, use a recommended drain valve. First, close water input into the
heater. Find necessary pressure values in the following table. For proper safety valve
operation, a backflow valve 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.

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Required pressures –Table 33. We recommend that the hot water distribution from the heater was as
short as possible to minimise heat losses.
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
Standards.
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
up to 0.8
Table 3
2.4 CONNECTING A HEATER TO A HEATING SYSTEM
The heater is placed on the ground, next to the heating source, or in its vicinity. 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.
An example of a group heater connection for steady hot water consumption from all tanks using
Tichelmann’s method
OV –Heating water
SV –Cold water
C - Circulation
TUV –Hot service water
1 –back pressure valve
2 - Pump
Figure 7

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2.5 HEATER CLEANING AND ANODE ROD EXCHANGE
Repetitive water heating causes limestone sediment on both the enamelled 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 hot water valve must be open
in order to avoid creating underpressure that would prevent water discharge.
To prevent the occurrence of bacteria (e.g. Legionella pneumophila) within stack heating it
is recommended, if absolutely necessary, to increase the temperature of hot service water
(HSW) periodically for a transitional period of time to at least 70°C. It is also possible to
make use of another way of disinfecting HSW.
2.6 SPARE PARTS
- Magnesium anode
- contact thermometer
When ordering spare parts, give part name, type, and type number from the heater label.
3IMPORTANT NOTICES
3.1 IMPORTANT NOTICES
Without a proof issued by a professional company about performed electrical and
plumbing fixture the warranty shall be void.
It is necessary to check the protective magnesium anode periodically and replace it if
necessary.
No stop valves can be put between the heater and the safety valve.
All outlets of hot water must be equipped with combination faucets.
Before the first filling of water heater it is recommended to tighten the nuts of the flange
joint of the tank..

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3.2 INSTALLATION REGULATIONS
Both the electric and water installation must follow and meet the requirements and
regulations relevant in the country of use!
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.
3-2014