Dražice OKC 300 NTR/1MPa User manual

OPERATING and INSTALLATION MANUAL
INDIRECT WATER HEATERS
OKC 300 NTR/1MPa OKC 300 NTRR/1MPa
OKC 400 NTR/1MPa OKC 400 NTRR/1MPa
OKC 500 NTR/1MPa OKC 500 NTRR/1MPa
OKC 750 NTR/1MPa OKC 750 NTRR/1MPa
OKC 1000 NTR/1MPa OKC 1000 NTRR/1MPa
Družstevní závody Dražice – strojírna s.r.o.
(Works Cooperative - Dražice – Machine Plant, Ltd.)
Dražice 69
29471 Benátky nad Jizerou
Tel.: [phone], fax: [phone]
www.dzd.cz
[e-mail]

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Read carefully the below instructions prior to the installation of 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.
The manufacturer reserves the right for engineering modification of the product.
The product is designed for permanent contact with drinkable water.
Guide Contents
1. USE.........................................................................................................................................................................................2
2. PRODUCT DESCRIPTION..................................................................................................................................................2
3. IMPORTANT NOTICE ........................................................................................................................................................3
4. PUTTING THE HEATER INTO OPERATION .................................................................................................................3
5. TECHNICAL DATA .............................................................................................................................................................3
6. CONNECTING A HEATER TO A HOT WATER DISTRIBUTION ................................................................................4
7. SECURITY EQUIPMENT....................................................................................................................................................4
8. SPARE PARTS ......................................................................................................................................................................5
9. HEATER CLEANING AND ANODE ROD EXCHANGE..................................................................................................5
10. INSTALLATION REGULATIONS....................................................................................................................................5
11. CONNECTING A HEATER TO A HEATING SYSTEM.................................................................................................5
12. PERFORMANCE DATA ....................................................................................................................................................7
14. ASSEMBLY GUIDE FOR ZIP-FASTENER INSULATION ............................................................................................9
15. CONSTRUCTION HEATER PARAMETERS................................................................................................................10
Environment Type:
It is recommended to use the product in indoor environment with air temperatures from +2°C to 45°C and a
max. relative humidity of 80%.
1. USE
Indirect stationary heaters lines NTR and NTRR are used for water heating in conjunction with another source
of heating water, most often a gas boiler. The NTRR types combine two sources of heating water (gas boiler + a
solar system or a heat pump). 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.
2. PRODUCT DESCRIPTION
The heater tank is welded from a steel sheet; it is entirely coated with hot water resistant enamel. 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 tank, hot and cold water and circulation
pipes; a thermostat well; and either one or two spiral steel pipe heat exchangers (enamelled on the outside) are all
welded on. The pipe heat exchanger is only intended for the heating circuit.
On the heater side, there is a cleaning and revision opening ending with a 110 mm flange; the clearance including
eight M8 bolts is 150 mm - 300 to 500 litres, for 180 mm clearance the spacing of ten bolts is 225 –750 o 1000
litres. A heating unit with various output containing an operating and safety thermostat can be mounted in the
opening. The NTR series heaters are equipped with a G 1 ½ " aperture for in-screwing an additional heating element.
Such version is used when the heater is connected to either a solar system or a system with a heat pump, to heat
water in the upper part of the heater to the temperature required. The tank is insulated with 50-80 mm of
polyurethane freon-free foam. The tank shell is made of a steel sheet painted with a powder coating (the 400-500 L
types only; other are in plastic) and the connecting parts are metal-coated.

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3. IMPORTANT NOTICE
-Check and exchange the Mg anode regularly.
-No stop valves can be put between the heater and the safety valve.
-All hot water outputs must have a mixing battery.
-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, 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.
-As an exception, the thermal fuse may also switch off due to water overheating caused by overheating
the hot water heating system boiler (in case of a combined heater).
-We recommend you operate the heater with one type of energy. In case a solar system is connected
to the bottom exchanger, it is necessary to connect a TJ 6/4" line element in the coupling above the
heater for potential additional heating.
4. PUTTING THE HEATER INTO OPERATION
After connecting a heater to the water main, 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.
Procedure:
Check both water and electric installation; for combined heaters, check the installation to a 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.
Open the hot water valve on the combination faucet
Open the cold water inlet valve to the heater.
As soon as the water starts running through the hot water valve, the heater is filled and the valve closes.
In case of a leakage (flange lid), we recommend fastening the flange lid bolts.
Fasten the electric installation cover.
In case of service water heating by electric energy, turn on the electricity (for combined heaters, the heating water
valve at the heating water entry to heating insert must be closed).
When heating service water with electric energy from the hot water heating system, turn the electricity off and open
the valves of heating water input and output, possibly de-aerate the exchanger. When commencing operation, flush
the heater until the cloudiness in the water is gone.
Make sure to fill in properly the warranty certificate.
5.TECHNICAL DATA
Chart 1
Type
OKC 300
NTR/1MPa
OKC 400
NTR/1MPa
OKC 500
NTR/1MPa
OKC 750
NTR/1MPa
OKC 1000
NTR/1MPa
Tank capacity l300 385 485 750 975
Diameter mm 670 700 700 910 1010
Weight kg 108 123 173 253 337
Operating hot service water pressure MPa 1 1 1 1 1
Operating heating water pressure MPa 1,6 1,6 1,6 1,6 1,6
Max temperature of heating water °C 110 110 110 110 110
Max temperature of hot service water °C 95 95 95 95 95
Exchanger heat surface m2 1,5 1,8 1,9 3,7 4,5
Exchanger performance at temperature drop 80/60°C kW 35 57 65 99 110
Performance number accord.to DIN 4708 NL 8 15,2 19,1 30,5 38,8
Permanent TUV* performance l/h 1100 1395 1590 2440 2715
TUV*heating time by exchanger at temperature drop 80/60°C min 24 20 23 24 26
Heat losses kWh/24h 1,86 2 2,3 3,6 3,9
*TUV - Hot service water 45°C

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Chart 2
6. CONNECTING A HEATER TO A HOT WATER DISTRIBUTION
Implement the connection in accordance with the scheme on page 6.
Scheme of Heater's Water Inputs and Outputs
OKC 300 NTR/1MPa, OKC 400 NTR/1MPa OKC 300 NTRR/1MPa, OKC 400 NTRR/1MPa,
OKC 500 NTR/1MPa OKC 500 NTRR/1MPa,
OKC 750 NTR/1MPa, OKC 1000 NTR/1MPa OKC 750 NTRR/1MPa, OKC 1000 NTRR/1MPa
The heater’s cold water inlet must be fitted with T-fittings with a discharge valve for any discharge of water from the
heater (see Section No. 11).
On the hot water input, each individually closable heater must have a test cock, backflow valve, safety valve, and a
manometer.
7. SECURITY EQUIPMENT
Each hot service water pressure heater must have a safety valve with a membrane spring. Nominal clearance of
safety valves is defined in the ČSN 06 0830 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. 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. 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
draining 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.
When assembling the security equipment, follow ČSN 06 0830.
Type
OKC 300
NTRR/1MPa
OKC 400
NTRR/1MPa
OKC 500
NTRR/1MPa
OKC 750
NTRR/1MPa
OKC 1000
NTRR/1MPa
Tank capacity l295 380 470 750 995
Diameter mm 670 700 700 910 1010
Weight kg 124 144 183 245 315
Operating hot service water pressure MPa 1 1 1 1 1
Operating heating water pressure MPa 1,6 1,6 1,6 1,6 1,6
Max temperature of heating water °C 110 110 110 110 110
Max temperature of hot service water °C 95 95 95 95 95
Upper exchanger heat surface m2 1 1,05 1,3 1,17 1,12
Lower exchanger heat surface m2 1,5 1,8 1,9 1,93 2,45
Exchanger performance at temperature drop 80/60°C kW 35/27 57/31 65/40 60/33 76/32
Performance number accord.to DIN 4708 upper exchanger NL 2,9 3,4 5,9 6,2 7,1
Performance number accord.to DIN 4708 lower exchanger NL 4,2 15,2 19,1 21 26
Permanent TUV performance* of upper exchanger l/h 1100 1395 1590 1460 1490
Permanent TUV performance* of lower exchanger l/h 670 740 970 815 780
TUV*heating time by exchanger at temperature drop 80/60°C min 24/16 20/14 23/16 37/28 43/37
Heat losses kWh/24h 1,68 2 2,3 3,6 3,9
*TUV - Hot service water 45°C
Safety valve
starting pressure
(Mpa)
Admissible operating
water heater pressure
(MPa)
Max pressure in
the cold water
pipe (Mpa)
0,6 0,6 do 0,48
0,7 0,7 do 0,56
1 1 do 0,8

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8. SPARE PARTS
- Magnesium anode
- contact thermometer
When ordering spare parts, give part name, type, and type number from the heater label.
9. 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 vessel from scale and eventual replacement anode rod after
two years of operation. 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 draining water from the heater, the mixing battery valve for hot water must be open, preventing occurrence of
under-pressure in the heater tank, which would stop the water from draining.
10. INSTALLATION REGULATIONS
Regulations and instructions that must be obeyed connect the heater
For the heating system
ČSN 06 0310 – Thermal systems in buildings –Designing and Installation
ČSN 06 0830 – Thermal systems in buildings –Protecting devices
to the electrical network
ČSN 33 2180 - Connecting of electric devices and appliances
ČSN 33 2000-4-41 - Low voltage electric installations Protective measure to ensure safety
- Protection from injury caused by electricity
ČSN 33 2000-7-701 - Low voltage electric installations: Single-purpose devices and devices in special premises -
Premises with tub or shower
to the hot water heating system
ČSN 06 0320 - Thermal systems in buildings - Hot water preparation –Design and Project Engineering
ČSN 06 0830 – Thermal systems in buildings –Protecting devices
ČSN 73 6660 – Internal water conduits
ČSN 07 7401 - Water and steam for thermal energy equipments with working steam pressure up to 8 MPa
ČSN 06 1010 - Tank water heaters with water and steam heating; and combined with electric heating.
Technical requirements. Testing.
ČSN 75 5455 –Calculation of water installations inside buildings
ČSN EN 12897 – Water supply –Indirectly heated closed tank-type water heaters
Both electric and water installation must follow and meet requirements and regulations relevant in the
country of use.
NOTICE
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 periodically for a transitional period of time to
at least 74 °C. It is also possible to make use of another way of disinfecting the hot water system.
11. 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; 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. Should the system work with priority heating of hot service water
using a three-way valve, always follow the installation instructions of the three-way valve’s manufacturer.

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OKC 300-1000 NTR OKC 300-1000 NTRR
heated by a gas boiler with two pumps heated by a gas boiler and solar collectors
Fig. 2 controlled by a three-way valve
An example of a group heater connection for steady hot service water consumption from all tanks using
Tichelmann’s method
Fig. 3
OV –Heating water TUV - Hot service water
SV - Cold water 1 - Back-pressure valve
C - Circulation 2 - Pump

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Type
tsv = 10°C ttv = 45°C tsv =10°C ttv = 45°C
tsp = 50°C tsp = 60°C tsp = 50°C tsp = 60°C
HV SV HV SV
°C - - - - l/h kW l/h kW l/h kW l/h kW l/10min l/10min m3/h kWh
OKC 300 NTRR/1MPa 50 1,1 1,8 - - 431 17,1 259 10,4 - - - - 111 -
60 1,3 2,2 1,6 2,6 594 24 348 14,1 446 18 261 10,6 127 152
70 1,7 2,7 2 3,3 818 33,6 468 19,1 614 25,2 351 14,3 145 174 2,7/2,7 1,68
80 2,1 3,4 2,5 4,1 1086 44,2 629 25,9 815 33,2 472 19,4 166 199
90 2,7 4,4 3,2 5,3 1299 52,6 757 30,6 974 39,5 568 23 161 217
OKC 400 NTRR/1MPa 50 3,2 5,3 - - 493 19,6 305 12,2 - - - - 221 -
60 3,7 6 4,4 7,2 679 27,4 410 16,6 509 20,6 308 12,4 243 292
70 4,2 6,9 5 8,2 935 38,4 551 22,5 701 28,8 413 16,9 268 321 3,0/3,0 2
80 4,8 7,8 5,7 9,4 1241 50,5 740 30,5 931 37,9 555 22,9 294 353
90 5,8 9,6 7 11,5 1485 60,1 891 26 1114 45,1 668 19,5 316 379
OKC 500 NTRR/1MPa 50 3,8 6,2 - - 583 23,5 395 15,9 - - - - 332 -
60 4,7 7,8 5,7 9,3 790 32 531 21,5 593 24 399 16,1 360 432
70 5,9 9,7 7,1 11,7 1070 43,5 715 29,2 803 32,6 536 21,9 390 468 3,0/3,0 2,3
80 7,4 12,2 8,9 14,7 1430 58 962 39,6 1073 43,5 722 29,7 423 507
90 9 14,8 10,8 17,8 1720 70 1157 46,8 1290 52,5 868 35,1 450 540
HV - upper exchanger
SV - lower exchanger
NL Power Factor at
tsv = 10°C
Permanent hot water output
Inlet
heating
water
temperatu
re
ttv = 60°C
ttv = 45°C
tsv = 10°C
SV
HV
SV
HV
Heating
water flow
Losses in
24 hrs
Flow in 10 minutes
tsv- cold water temperature
ttv- hot water temperature
tsp- medium temperature of the heater
12. PERFORMANCE DATA
Chart 3
Chart 4
NL Power Factor
Based on DIN, the expression of a normal flat is introduced for apartment houses in the FRG. Such a flat has four rooms; it is
occupied by 3.5 people; it has a bathtub, a hand basin, and a sink. Flats of other sizes, number of occupants and different
equipment are converted to normal flats using the relations given in the standard (NL). The situation in our apartment houses,
massively built until the recent past, is similar.
Flats intended for 3 to 4 people are equipped identically with normal German flats. Smaller flats tend to have smaller bathtub or
Type
tsv = 10°C ttv = 45°C tsv =10°C ttv = 45°C
tsp = 50°C tsp = 60°C tsp = 50°C tsp = 60°C
°C - - l/h kW l/h kW l/10min l/10min m3/h kWh
OKC 300 NTR/1MPa 60 4,3 - 617 25,1 - - 290 -
70 5,3 8,4 888 36,1 622 26,8 322 403
80 5,3 8,4 1100 47,4 816 39,8 358 448 2,7 1,68
90 5,3 8,4 1451 59 1015 52,5 398 497
OKC 400 NTR/1MPa 60 6,8 - 738 29,9 - - 399 -
70 10,1 12,8 990 43,2 745 32,1 443 554
80 10,1 15,2 1394 56,7 976 47,6 492 615 3 2
90 10,1 15,2 1733 70,4 1212 62,7 547 684
OKC 500 NTR/1MPa 60 11,3 - 842 34,2 - - 500 -
70 15,2 15,8 1210 49,2 847 36,7 556 694
80 15,2 19,1 1584 64,4 1109 54,2 617 771 3 2,3
90 15,2 19,1 1965 79,9 1376 71,2 686 858
OKC 750 NTR/1MPa 60 12,9 - 1279 52 - - 817 -
70 15,4 25,6 1828 74 1364 56 848 1060
80 18,3 30,5 2437 99 2065 84 880 1100 5 3,6
90 21 35 3046 124 2719 111 928 1160
OKC 1000 NTR/1MPa 60 16,6 - 1424 58 - - 862 -
70 19,7 32,8 2034 83 1518 62 908 1135
80 23,3 38,8 2712 110 2298 94 957 1197 6 3,9
90 27 45 3390 138 3026 123 1003 1254
HV - upper exchanger tsv- cold water temperature
SV - lower exchanger ttv- hot water temperature
tsp- medium temperature of the heater
Inlet
heating
water
temperatur
e
NL Power Factor at
Permanent hot water output
Flow in 10 minutes
Heating
water flow
Losses in
24 hrs
ttv = 45°C
ttv = 60°C
tsv = 10°C

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a shower; larger, so-called two-generation flats tend to have an extra hand basin. Apartment buildings with luxury flats and
high standard equipment, with higher number of fittings, or fittings equipped with high standard drain armatures, both hot water
and heat energy needs must be adjusted.
13. PRESSURE LOSSES
Fig. 4
Fig. 5

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Disposal of Packaging Material
For the package, in which the water heater was delivered, the service fee for back taking and utilisation of the
packaging material was paid.
The service fee was paid in accordance with Act No. 477/2001 Coll., as amended by later regulations of EKO-KOM
a.s.
Company client number is F06020274.
Dispose of the water heater packages in a location determined
as the waste storage by the town.
Disposal of old water heater
After operation termination, disassemble and transport the dead and
unserviceable heater
to a waste recycling centre (collection yard), or to a bulk waste collection yard.
14. ASSEMBLY GUIDE FOR ZIP-FASTENER INSULATION
Only concerns heaters with the capacity of 750 and 1000 litres
Two people are enough to implement the assembly; three people are required for larger boilers; the assembly
must be implemented in areas with the temperature of at least 18oC.
If the insulation includes tank bottom insulation, the latter must be mounted first. Consequently, the
insulation is inserted around the boiler; pre-pressed insulation openings must be respected.
By slight pull in the direction of the arrows, pull both sides of the zip-fastener insulation so that (as shown on
Fig. 6) the insulation does not slide and the insulation holes sit on the boiler inlets and outlets.
It must be secured that before closing, both halves of the zip-fastener were not further than 20 mm apart (see
Fig.7). No foam shall get into the zip-fastener on closing.
After the insulation coat is properly mounted and the zip closure closed properly, insert the top lid made of foam
material and cover it with either a foil cover or a plastic lid. It is also possible to glue the outlet caps to connection
places (see Fig. 8). The insulation may only be stored in dry storage places.
We take no responsibility for damages caused by not respecting this guide.

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Fig. 6 Fig. 7 Fig. 8
15. CONSTRUCTION HEATER PARAMETERS
OKC 300 NTR/1MPa, OKC 300 NTR/1MPa
Fig. 9

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Fig. 10
OKC 400 NTR/1MPa, OKC 500 NTR/1MPa
Fig. 11
OKC 400 NTRR/1MPa, OKC 500 NTRR/1MPa
OKC 400 NTR/1MPa OKC 500 NTR/1MPa
A1591 1921
B1523 1853
C1111 1264
D1 597 597
D2 700 700
E909 965
F684 695
G957 1040
H369 388
OKC 400 NTRR/1MPa OKC 500 NTRR/1MPa
A1631 1961
B957 1040
C275 275
D1 597 597
D2 700 700
E1523 1853
F1354 1604
G1223 1409
H1111 1264
I1006 1114
J909 965
K369 380
L220 220
M55 55
N25 25

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Fig. 12
OKC 750 NTR/1MPa, OKC 1000 NTR/1MPa
Fig. 13
OKC 750 NTRR/1MPa, OKC 1000 NTRR/1MPa
05-2012
OKC 750 NTRR/1MPa OKC 1000 NTRR/1MPa
A1998 2025
B1005 1025
C378 387
D1 750 850
D2 910 1010
E1887 1905
F1467 1423
G1375 1375
H1242 1243
I1151 1153
J830 884
K402 411
L297 297
M99 103
N55 45
O1643 1672
OKC 750 NTR/1MPa OKC 1000 NTR/1MPa
A1998 2025
B1887 1905
C1417 1490
D1 750 850
D2 910 1010
E1314 1324
F1079 1087
G288 295
H99 103
I1643 1672
J1005 1025
K375 385