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.: [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.
With this guide, we will introduce you to the use, location, construction, maintenance and other information on the tank
type pressure water heater.
Product’s reliability and safety is proven by tests implemented by the Engineering Test Institute in Brno.
We believe you will be fully satisfied with our product.
The manufacturer reserves the right for engineering modification of the product.
The product is designed for permanent contact with drinkable water.
Guide Contents
1. FUNCTION DESCRIPTION..................................................................................................................... 2
2. MESSAGE FOR CUSTOMERS................................................................................................................ 3
3. TECHNICAL DESCRIPTION .................................................................................................................. 3
4. OPERATING ACTIVITY.......................................................................................................................... 4
5. SERVICING............................................................................................................................................... 4
6. PLUMBING FIXTURE ............................................................................................................................. 5
7. CONNECTION OF INDIRECT HEATER TO HOT WATER HEATING SYSTEM ............................. 6
8. ELECTRIC INSTALLATION................................................................................................................... 7
9. PUTTING THE HEATER INTO OPERATION ....................................................................................... 8
10. HEATER CLEANING AND ANODE ROD EXCHANGE...................................................................... 8
11. IMPORTANT NOTICES........................................................................................................................... 8
12. FIRE-FIGHTING REGULATIONS FOR INSTALLATION AND USE OF HEATER .......................... 9
13. INSTALLATION REGULATIONS .......................................................................................................... 9
14. MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES ................................................... 9
15. PRODUCT ACCESSORIES...................................................................................................................... 9
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%.
Placement:
The heater is placed on the ground, next to the heating water source, or in its vicinity. All wiring connections
must be properly insulated from heat.
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.

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2. MESSAGE FOR CUSTOMERS
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.
Energy saving
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.
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.
- Continuously adjustable temperature of hot utility water| up to 74°C
- Connection of multiple withdrawal points.
- Heater operation control light.
- Accurate check of hot service water temperature.
- Possibility of connecting hot service water circulation.
3. TECHNICAL DESCRIPTION
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, OKHC 160 NTR,

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Technical description:
OKH 100 NTR/HV, OKH 125 NTR/HV
4. OPERATING ACTIVITY
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 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 (Fig. 1) as needed, in particular before the beginning of the heating season.
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 (Fig.1).
5. SERVICING
Service devices of heaters of 100 to 160 l capacity are located under the transparent guard of the control panel.
PANEL OF OKH NTR & OKH NTR/HV HEATERS of 100 up to 160 l capacity

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Temperature setting
Water temperature is set by turning the thermostat knob. The desired symbol is adjusted against the fixed point on the
control panel.
Notice: Adjusting the thermostat selector at the left backstop does not mean permanent shutoff of the heating element.
When the heater is in use without blocking the daily rate, we do not recommend the temperature to be set above 65°C.
The maximum value to select is “60“.
Limiting the regulation range; locked settings. (Applies to 100 up to 160 l capacities only.)
For various safety reasons (unintentional scalding, preventing children or unauthorised person from handling), the
regulation range can be limited, or the setting on the thermostat blocked.
Limited regulation –pull off the thermostat knob (it will be hard for the first time), and you will find
two 2.15mm cylindrical pins on the back side of the knob
- pull off one pin and insert it to the corresponding hole of the selected maximum temperature.
- put the knob back on (to the stop).
Setting blocked –set the selected temperature
pull off the thermostat knob without changing the setting, there are two pins on the back side of the
knob.
Pull off both of them and fit them to the holes corresponding with the selected temperature so that the
gap between the pins was without a hole, and the position was opposite the set temperature.
6. PLUMBING FIXTURE
Connection of heaters to plumbing fixtures is illustrated on Fig.1. 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 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 NTR / HV types are equipped with a discharge outlet.
Connection of heaters to plumbing fixtures is illustrated on Figures 1 and 2. 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 safety valve with a membrane spring. Nominal clearance of safety
valves is defined in the ČSN 0 60830 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
Lower temperature range
limit (about 5°C)
Fixed point on the control
panel
Anti-freezing temperature
(about 8°C)
Upper temperature range
limit (about 74°C)
”Ideal” temperature
(about 60°C)
Regulation limited
Setting blocked

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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 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.
Heaters must be provided with a discharge valve mounted on the cold service water inlet to the heater (Fig. 2) for
potential disassembly or repair.
When assembling the security equipment, follow ČSN 06 0830.
7. CONNECTION OF INDIRECT HEATER TO HOT WATER HEATING SYSTEM
(examples of connection + Fig. 1)
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 hot service water using a three-way valve, always follow the installation instructions of the three-way valve’s
manufacturer.
Safety valve starting
pressure (MPa)
Admissible operating
water heater pressure
(MPa)
Max. pressure in the cold
water pipe (MPa)
0.6
0.6
up to 0.48
0.7
0.7
up to 0.56
1
1
up to 0.8

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Examples of connection of the heater to water and heating system
8. ELECTRIC INSTALLATION
Electric connection of heater:
OKH 100 NTR, OKH 125 NTR, OKH 160 NTR
OKH 100 NTR/HV, OKH 125 NTR/HV
Check insertion of the thermostat sensor in the thermowell, the so-called insertion all the way.
The heater can be connected to any hot water heating boiler up to the power output of 50 kW. Electrically, the heater is
powered directly by boiler with 230 V/50Hz control voltage. Elastic cable CYSY 4C x 0.75 can be used for
interconnection. Connecting terminals are identified on the terminal board of the heater.
- there is voltage on connecting terminal 2 when heater is heated
- there is voltage on connecting terminal 1 when heater is not heated
Installations in bathrooms, lavatories and showers must obey
the ČSN33 2000-7-701 standard.
Capillary thermometer is installed on the control panel to
control the temperature of water, additionally there is a capillary
thermometer control device to set the desired water temperature and
two signal lights –“green” – heater heated, and “orange” – heating
in process.

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9. PUTTING THE HEATER INTO OPERATION
After connecting the heater to the water main, hot water heating system and power supply, and after checking the safety
valve (following the instructions attached to the valve), the heater can be put into operation.
Procedure:
a) Check both water and electric installation; for combined heaters, check the installation to a hot water heating
system. Check proper placement of thermostat sensors; The sensors in the thermowell have to be inserted all the
way.
b) Open the hot water valve on the combination faucet
c) Open the cold water inlet valve to the heater.
d) As soon as the water starts running through the hot water valve, the heater is filled and the valve closes.
e) In case of a leakage (flange lid), we recommend fastening the flange lid bolts.
f) Fasten the electric installation cover.
g) 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.
h) When commencing operation, flush the heater until the cloudiness in the water is gone.
i) Make sure to fill in properly the warranty certificate.
10. HEATER CLEANING AND ANODE ROD EXCHANGE
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
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.
11. IMPORTANT NOTICES
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 hot water outputs must have 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, adjustment and replacement of the regulation
elements shall only be performed by an authorised service company.
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 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.

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12. FIRE-FIGHTING REGULATIONS FOR INSTALLATION AND USE OF HEATER
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.
13. INSTALLATION REGULATIONS
Regulations and instructions that must be obeyed if the heater is connected
a) to the heating system
ČSN 06 0310 – Thermal systems in buildings –Designing and Installation
ČSN 06 0830 – Thermal systems in buildings –Protecting devices
b) to the electrical network
ČSN 33 2180 - Connecting of electric devices and appliances
ČSN 33 2000-4-41 - Low voltage electric installations Protective measures to ensure safety –Protection against
electric shock
ČSN 33 2000-7-701 - Low voltage electric installations Single-purpose devices and devices in special premises
- Premises with tub or shower to hot service water heating system
c) 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 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.
14. MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES
Water is dripping off the safety valve –glow lamp is off –faulty safety valve, high water pressure at the inlet
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.
15. PRODUCT ACCESSORIES
G3/4" safety valve is packed with the product and the OKH 100, 125, 160 NTR and OKH 100, 125
NTR/ HV types are additionally equipped with a discharge valve.
It is in your own interest to check the completeness of the accessories.

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Fig. 1
Connection of the heater exchanger (left, right) and fittings at the cold water inlet
Technical Data
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
Connection on the cold water inlet must conform to
ČSN 060830
Type OKH 100 NTR/HV OKH 125 NTR/HV
Capacity l95 120
Weight kg 56 70
Heat transfer surface
m21,08 1,45
Max tank pressure MPa
Max pressure of exchanger MPa
Max temperature of HSW °C
Recommended HSW temperature °C
HSW connection
Heating water connection
El.protection
Connecting voltage
Rated thermal output at water
temperature of 80°C and flow 720 l/h
W24000 32000
Heating time from 10 to 60°C by exchanger
min 14 14
Heat losses kW/24h
G 3/4"
G 3/4"
IP44
1 PEN AC 230V, 50 Hz
0,6
1
80
60
Type OKH 100 NTR OKH 125 NTR OKH 160 NTR
Capacity l95 120 160
Weight kg 57 69 77
Heat transfer surface
m21,08 1,45 1,45
Max tank pressure MPa
Max pressure of exchanger MPa
Max temperature of hot service water °C
Recommended hot service water temperature
°C
HSW connection
Heating water connection
El.protection
Connecting voltage
Rated thermal output at water
temperature of 80°C and flow 720 l/h
W24000 32000 32000
Heating time from 10 to 60°C by exchanger
min 14 14 17
Heat losses kW/24h
IP44
1 PEN AC 230V, 50 Hz
0,6
1
80
60
G 3/4"
G 1"

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Dimensions of heaters
OKH 100 NTR, OKH 125 NTR, OKH 160 NTR
OKH 100 NTR OKH 125 NTR OKH 160 NTR
A887 1052 1237
B* 882 1047 1232
C621 751 751
D521 621 881
*Height from the bottom heater's edge to the end of the water inlet and outlet tubes.

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OKH 100 NTR/HV, OKH 125 NTR/HV
OKH 100 NTR/HV
OKH 125 NTR/HV
A
887
1052
B*
882
1047
C
127
127
*Height from the bottom heater's edge to the end of the water inlet
and outlet tubes.
2-2014
5x3/4“