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.
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. 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.
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.
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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 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.
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 lower bottom of the receptacle with a flange lid screwed onto 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(s) is/are welded onto the pressure tank.
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 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 (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 80 to 250 l capacity are located under the transparent guard of the control panel.
PANEL OF OKC NTR / Z & OKCV NTR HEATERS of 80 up to 200 l capacity
Thermostat knob Electric circuit closing indicator lamp Tipping transparent guard
PANEL OF OKC NTR,R & OKC NTR / HV HEATERS of 100 up to 250 l capacity
Temperature setting
Teplota vody se nastavuje otočením knoflíku termostatu. Požadovaný symbol se nastaví proti pevnému bodu na
ovládacím panelu.
Lower temperature range
limit (about 5°C)
Fixed point on the control
panel
Anti-freezing temperature
(about 8°C)
Notice: Adjusting the thermostat selector to the left backstop does not mean permanent shutoff of the heating element.
Upper temperature range
limit (about 74°C)
”Ideal” temperature (about
60°C)
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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.
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.
Regulation limited: - pull off the thermostat knob (it will be hard for the first time), and you will find two φ2.15mm
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
Regulation limited Setting blocked
To block the setting: - 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 into 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 (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.
The heaters must be equipped with a drain valve.
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.
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.
When assembling the security equipment, follow ČSN 06 0830.
Safety valve
starting pressure
(MPa)
0.6 0.6 do 0.48
0.7 0.7 do 0.56
1 1 do 0.8
Admissible operating
water heater
pressure (MPa)
Max. pressure in
the cold water pipe
(MPa)
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7. CONNECTION OF INDIRECT HEATER TO HOT WATER HEATING SYSTEM
(Fig. Examples of connection… and 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 HSW using a three-way valve, always follow the installation instructions of
the three-way valve’s manufacturer.
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Examples of connection of the heater to water and heating system
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8. WALL MOUNTING (applies to NTR/Z & OKCV NTR only)
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 (Fig. 5, 6). 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 (Fig. 1).
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.
9. ELECTRIC INSTALLATION
Check the 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/50 Hz 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.
Electric connection to heaters of the below types:
- 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, showers and lavatories must obey
the ČSN33 2000-7-701 standard.
Touch thermometer is installed on the control panel to control the
temperature of water, additionally there is a capillary thermostat to set the
desired water temperature and two signal lights: “green” – heater heated,
and “orange” – heating in process.
Electric connection to heaters of the below types:
- there is voltage on connecting terminal 1 when heater is
not heated
The touch panel features control of the capillary
thermostat to set the desired temperature of water, and the
orange control lamp is on when the heater is heating.
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10. PUTTING THE HEATER INTO OPERATION
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.
Procedure:
a) 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 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.
11. 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 discharging water from the heater, the combination faucet valve for hot water must be open in order to avoid
creating underpressure that would prevent water discharge.
12.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 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.
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 product packages to a waste disposal place designated to that purpose by the
municipality. 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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13. FIRE-FIGHTING REGULATIONS FOR INSTALLATION AND USE OF HEATER
Temperature of water is not
Water is constantly dripping
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.
14. 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) for electric 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 bathtub or shower
c) to the HSW 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 mains
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.
15. MOST FREQUENT FUNCTION FAILURES AND THEIR CAUSES
corresponding with the set
Defective thermostat
value
of the safety valve
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
LED is not on Input pressure too high; faulty safety valve
performance plate of your water heater.
16. 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. The OKC NTR/Z and OKCV NTR types packaging include
suspension elements and thermometer.
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
Connection to the cold water inlet
must conform to ČSN 060830.
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
Fig. 2
Fitting of hinges and thermometer
onto the heater
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Fig. 3
OKC 200 NTR
OKC 200 NTRR
OKC 250 NTR
OKC 250 NTRR
*Height from the bottom heater's edge to the end of the water inlet and outlet tubes