Flexiheat THERMO-Combi 15 User manual

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TMS-UT-0709-Z07-8
ELECTRIC BOILER FOR CENTRAL HEATING
AND WARM WATER PREPARATION
USER’S INSTRUCTIONS
THERMO-COMBI

We reserve the right of changing these instructions without special prior notification

We reserve the right of changing these instructions without special prior notification
WE ARE NOT LIABLE FOR
DAMAGES RESULTING
FROM NON-OBSERVING
THESE INSTRUCTIONS
Safety information and warnings
•Keep these instructions in the vicinity of
the boiler!
•The boiler is not allowed to modify.
•Adjusting correctly is important for
economical heating.
•At each contact with the manufacturer or
authorized service call to the factory-a
number that is printed on the identification
label on the boiler.
Children in the household!!!
- Please supervise children who are
retained in the vicinity of the device. Do
not allow children to play with the device.
- User cleaning and maintenance may not
work children unattended.
- The boiler is not intended for the
installation in the open air.
Technical security!!
- Keep the water pressure in the boiler
according to the manufacturer's
recommendations-see section 3.2.
- Do not mount the boiler in the vicinity of
sources of heat (open fireplace, wood stove,
etc.).
- Defective parts may be replaced only with
original or approved by the manufacturer.
- Turn off the main power before opening or
any work on the boiler.
- The boiler has a built-in protection against
frost damage. If the boiler in winter period
does not use mandatory should be left active
main power (boiler can be turned off on the
control panel) so that the protection was
active.
Table of contents
Safety information and warnings ........................3
1. Introduction ....................................................1
2. About the product...........................................1
2.1. Construction .....................................................1
......................................................3
3.1. Important warnings...........................................3
3.2. Assembly..........................................................3
3.2. Assembly (Continued)......................................4
3.3. Power supply connection .................................5
3.4. Connecting temperature sensors, room
thermostat or external electrical controls ........6
3.4.1. Accessing connection plate......................6
3.4.2. Connecting sensors or room thermostat on
connection plate ..................................................6
4. Use of the product..........................................7
4.1. Control panel....................................................7
4.1.1. Central heating functions ..........................8
4.1.2. Domestic water functions ..........................9
4.1.3. Access to special service menu ..............11
4.2. Use of the boiler .............................................12
4.3. Manipulation with automatic equipment.........13
4.4. Recommendations for optimal use ................15
5. Maintenance ................................................15
6. Survey of possible defects and irregularities in
operation .....................................................16
7. Technical specification .................................18
Read this document carefully before
manipulation, any installation, setup,
or service, and follow the instructions
- Improper repairs can cause a serious danger
to the safety of the user.
2
3. Installation
2.2. Integral parts of the THERMO-Combi Boiler ......

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1
1. Introduction
Illustration of unpacked product
2. About the product
The boiler is operated on the principle of rapid heating
smaller water quantities and its energy exploitation is
almost 100%
Temperature range of operation is for sanitary water
from 30oC up to 55 oC, for central heating from 30oC
up to 90 oC.
2.1. Construction
At the bottom side of the boiler there are built in
electric heaters. From the upper side there is the blind
tube for placing the sounding tube of capillary
thermostat, temperature, pressure and thermal fuse
indicator. The boiler is insulated with 19 mm self-
extinguishing insulating material, which is sufficient to
direct all the heat only to the heating and sanitary
water preparation system.
Thank you for the confidence you have shown to us
by having purchased our boiler for central heating and
sanitary water preparation.
For correct and safe and above all economic use
of the product, before assembly and connection,
read thoroughly these instructions.
Packing contains the following elements: boiler (1),
suspension support (3), user’s instructions and letter
of guarantee (3), valve for filling and emptying (4),
impurities collector (5), plastic pipe for venting the
system.
The Thermo-Combi boilers meet any and all national
regulations and legal standards. Pursuant to the
mentioned before, the certification of the product was
done according to the valid EN and HRN standards.
You can take insight into the certificates at the point of
sale,authorized service
THERMO-Combi is the economic boiler for
central heating and sanitary water preparation that
may be used as the independent source of heat.
THERMO-Combi is suitable for using in smaller
business premises, flats, smaller catering objects etc.,
where it is important that it takes up small space.
The electric boiler THERMO-Combi is made of quality
boiler metal sheet. The boiler itself is upon welding
sandblasted and protected with quality reactive
fundamental color.
Because of its design and noise free operation, the
THERMO-Combi may easily fit in the living space.
The outer metal sheet is protected by powder coating.

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2
1. Central heating primary flow
2. Central heating return flow
3. External shell of the boiler
4. Boiler
5. Thermal insulation
6. Electric heaters
7. Control panel
8. Boots for el. terminals
9. Contactors
10. Expansion vessel
11. Central heating pump
12. Safety valve at 3 bar
13. Automatic venting valve
14. Filling and emptying valve (in packing, it should
be built in at installation)
15. Valve for boiler venting
16. Sounding tube for air appearance control
17. Distributor
18. Miniature circuit breaker (MCB)
19. Temperature sensor of sanitary water outlet line
20. Exchanger
21. Temperature sensor of sanitary water inlet line
22. Non-return valve
23. Pump for sanitary water preparation
24. Sanitary water intake
25. Sanitary water output
26. Safety valve at 8 bar
27. Automatic venting valve
28. Boiler’s temperature sensor
2.2. Integral parts of the THERMO-Combi Boiler

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3
3. Installation
3.1. Important warnings
•THE BOILER SHOULD BE PUT INTO
OPERATION BY THE AUTHORIZED SERVICE,
•THE ENCLOSED IMPURITIES COLLECTOR
SHOULD BE BUILT IN ON THE STARTING LINE
OF CENTRAL HEATING AND INLET COLD
SANITARY WATER,
•PRIOR TO CONNECTING THE BOILER TO THE
SANITARY WATER LINE, PIPES SHOULD BE
CLEANED IN ORDER TO AVOID THE
BLOCKAGE OF THE EXCHANGER.
THE LIST OF AUTHORIZED SERVICES IS ON THE
BACK OF THE LETTER OF GUARANTEE
THE BOILER SHOULD NOT BE INSTALLED ON
PLACEC WHERE THERE IS A DANGER OF BEING
PORING OVER WITH WATER OR A DANGER OF
SINKING.
IN AREAS WITH STRONG CONCENTRATION OF
LIME IT IS RECOMMENDED TO BUILD IN A
MAGNETIC OR ELECTROMAGNETIC LIME
BREAKER ON THE INLET LINE OF SANITARY
WATER ON THE BOILER.
3.2. Assembly
Minimum distances at assembly
Disassembly schema
THERMO-Combi is foreseen for the wall assembly
and for the easier assembly, on the backside
there is foreseen the suspension support. For the
suspension you may use metal wall plugs with the
screw M8 or M10 or stronger plastic wall plugs – diana
screws.
Precise dimensions of boilers are given in the 7.
Technical specification
Filling and emptying valve is delivered together
with the boiler and should be assembled at the
installation.
If possible, the boiler should be assembled to the
lowest point in relation to installation. In this way we
are protecting the boiler from air appearance, which
may leave heaters without water that could result in
their burning through.
THE GUARANTEE SHALL NOT
BE ACCEPTED IF THE
FOLLOWING WAS NOT
OBSERVED:

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4
3.2. Assembly (Continued)
Prior to putting into operation, the system should
be vented and that both central heating and
sanitary water circle.
Upper side of Thermo-Combi
Switchboard for Thermo-Combi 15-24kW
Switchboard for Thermo-Combi 28-40kW
Illustration of how to correctly vent the water circle on
upper side of Thermo-Combi. Protection cap should
be release on automatic venting pots (1 and 2).
Plastic pipe should be attached to valve (3) prior
venting the water circle.
Thermo-Combi 15-24kW
On the illustration you can see: ground terminal (1),
neutral wire terminal (2), operating current trips (3),
MCB (miniature circuit breaker) (4), cartridge fuse
6.3A/T for control power (5), cartridge fuse 6.3A/T for
safety thermostat (STB) (6) and PCB with power
relays and connectors for pumps, room ‘stat and all
probes - (RelBoard) (7).
Thermo-Combi 28-40kW
On the illustration you can see: ground terminal (1),
neutral wire terminal (2), operating current trips (3),
MCB (miniature circuit breaker) (4), cartridge fuse
6.3A/T for control power (5), cartridge fuse 6.3A/T for
safety thermostat (STB) (6), contactors (quantity of
elements depends about nominal rated power of
boiler) (7) and plate with connectors for pumps, room
‘stat and all probes (8).

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5
3.3. Power supply connection
Note:
Before working on the boiler, turn off the power (e.g. MCB, switches) and secure against
accidental switching on. Tightening torque for MCB is 2.0 Nm.
A boiler is rated as a high power appliance and fixed wiring must be used. Please observe chapter 2.4.
about fuse and conductor requirements. When connecting the appliance to the fixing wiring, the means for
disconnection (MCB) must be incorporated in fixing wiring in accordance with the local wiring rules.
This device must be earthed.
Power connection (main power terminals):
Type A Type B
Connection way to the main power terminal may be vary depending on elements
installed inside the boiler.
Note:
The power cable of the intersection from Ø6 mm to Ø21 mm must be
connected with the bottom of the boiler, with the help of a special
introducetor (located on the boiler).
All wires inside the electrical connection place must be tighted.
Pay attention when connecting the power cable so that the phase conductor is not
mistakenly connected to the remote shunt release marked by "-KF11", to the right of the MCB.

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6
3.4. Connecting temperature sensors, room thermostat or external electrical controls
3.4.1. Accessing connection plate
In order to access connection plate (2) power connection protection cover (1) must be removed by unwinding two
M4 screws and pulling protection cover out. After connecting the power cable, protective cover (1) must be put in
place and tightened.
2 1
Accessing connection plate (15-24kW) Accessing connection plate (28-40kW)
3.4.2. Connecting sensors or room thermostat on connection plate
Temperature sensors
Connection plate (28-40kW)
Room thermostat
Connection board with relays (15-24kW)

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7
4. Use of the product
4.1. Control panel
Figure 1 - Control panel “Z” - OPTION
1. Multipurpose – temperature indicator (temperature of
boiler, sanitary water, adjustment of temperature)
2. Signalization of operation degree of heaters (1., 2., 3.)
3. Signalization of boiler operation (green light
4. Adjustment of temperature in boiler
5. Push button for central heating switching on and off
6. Sanitary water temperature adjustment
7. Push button for switching on and off the sanitary
water preparation
6. Signalization of sanitary water preparation and
consumption
9. Indicator of pressure in a boiler
10. Thermal fuse
Switching on of central heating
By pressing the push button (5), the central heating system is switched on. Upon pressing on the desired water
temperature in boiler is displayed for 5 seconds, signalization of central heating operation (3) is twinkling. After 5
seconds the real temperature in the boiler is displayed (1); if the current temperature in the boiler meets the desired
one, the signalization lamp of the operation mode (3) is switched off.
Adjustment of desired temperature of central heating
By pressing the push button for temperature adjustment (4) the desired temperature in the boiler appears, the
signalization lamp of the boiler operation (3) is twinkling. By repeated pressing upwards or downwards it is possible
to increase or decrease the desired water temperature. When the temperature is adjusted it is sufficient to wait for
5 seconds (signalization lamp of the boiler operation (3) does not twinkle) in order for the boiler to memorize new
temperature.

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8
Switching on of domestic water heating
By pressing the push button (7), the DHW system is switched on. Upon pressing on the desired water temperature
in boiler is displayed for 5 seconds, signalization of DHW operation (8) is twinkling. After 5 seconds the real
temperature in the boiler is displayed (1)
Adjustment of desired temperature of central heating
By pressing the push button for temperature adjustment (6) the desired temperature in the boiler appears, the
signalization lamp of the boiler operation (8) is twinkling. By repeated pressing upwards or downwards it is possible
to increase or decrease the desired water temperature. When the temperature is adjusted it is sufficient to wait for
5 seconds (signalization lamp of the boiler operation (8) does not twinkle) in order for the boiler to memorize new
temperature.
4.1.1. Central heating functions
Display of desired temperature in the boiler
If the key (4) is held pressed less than 5 s the LED display will
show the desired temperature in the boiler. The value is
displayed for 5 seconds, after which the display normally shows
the real temperature of water in the boiler.
Setting the desired temperature in the boiler
By pressing the key (4) user can enter the boiler temperature
menu.
The desired boiler temperature is blinking.
By pressing the key (4) UP or DOWN, the desired boiler
temperature can be set in steps of 1°C.
If the key is held pressed less than 5 s the value from the display
becomes the desired boiler temperature.
Possible adjustment is from 20°C up to 90°C for radiator
heating.
Possible adjustment is from 15°C up to 45°C for under floor
heating.
Reset to factory defaults
By pressing the key (4) longer than 15 seconds, all parameters
will return to the factory default values and controller will be
reset.

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9
4.1.2. Domestic water functions
Display of desired temperature of domestic water
If the key is held pressed less than 5 s the LED display will show
the desired temperature in domestic water storage. The value is
displayed for 5 seconds, after which the display normally shows
the real temperature of water in the boiler.
Setting the desired temperature in domestic water storage
By pressing the key (6) user can enter t
he domestic water
temperature menu.
The desired water temperature in domestic water storage is
blinking.
By pressing the key (6
) the value of desired domestic water
temperature in domestic water storage is changing in steps of
1°C. If the key is held pressed less than 5 s the value from the
display becomes the desired domestic water temperature.
Possible adjustment is from 10°C up to 65°C.
Factory adjustment is 50°C.
Displaying software version and factory reset
By pressing the key (6) longer than 15 s, the LED will show the
software version and the factory reset of central heating
parameters will occur.

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10
Continuation...
Display of current temperature in the domestic water storage
By pressing the key down (6
) user can select the display of
current temperature in the domestic water storage. The value is
displayed for 5 s, after which display returns to indication of the
actual temperature of water in the boiler..
Setting additional working time of domestic water pump
By pressing the key (6) user can setup additional working time of
domestic water pump.
The time of supplemental operation of circulation pump
operation for domestic water conditioning is blinking.
By pressing the key the time is changing from 0,1 min up to 19
min. In increment of 0,1. If the key is depressed for more than
5s, value on the display will be memorized and becomes active.
Factory default: 1 min.
Setting standby boiler temperature
By pressing the key (6
) user can setup stand by boiler
temperature
Display will show current standby boiler temperature.
Pressing the key (6) will change standby temperature by 1°C. If
the key is depressed for more than 5s, value on the display will
be memorized and becomes active.
Adjustment range: 10°C - 50°C
Factory default: 15°C
Reset to factory defaults
By pressing the key (6) longer than 15 seconds, all parameters
will return to the factory default values and controller will be
reset.

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11
4.1.3. Access to special service menu
Access to special service menu
Limiting maximum boiler temperature
By pressing the key (4) user can limit maximum boiler
temperature.
Factory defined maximum temperature starts to blink. By
pressing up or down user can set new maximum
temperature. If the key is depressed for more than 5s, value
on the display will be memorized and becomes active.
Adjustment range 60°C-90°C, factory default 80°C
Setting the minimal boiler temperature
By pressing the key (4
) user can set minimal boiler
temperature.
Minimal boiler temperature starts blinking.
By pressing the key user can select the desired minimal
boiler temperature. Temperature changes in steps of 1°C. If
the key is depressed for more than 5s, value on the display
will be memorized and becomes active.
Adjustment range 20°C-45°C, factory default 45°C
Setting the central heating pump delay
By pressing key (4) user can change pump delay time
between 0 - 15 min. Factory settings is 2.
Selecting the time delay between steps for power
regulation
By pressing the key (4) user can change the time delay
between steps for power regulation in the range from 5 to 60
seconds. Default value depends on the number of stages for
power regulation – each stage will add 5 seconds. For
example, 3 stages will have 3*5=15 seconds between
successive stages turn-on, 7 stages will have 7*5=35
seconds between sucessive stages turn-on. Turn of delay is
fixed to 1 second.
Selecting the number of steps for power regulation
By pressing the key (4) servicer can change the number of
steps for power regulation.
By pressing the key it is possible to select 2 to 7 steps for
power regulation. Default settings:- 3 power levels. Change
in the number of stages will cause time delay parameter to be
changed (see below) !
Note:
If boiler power is limited, power of central heating
will be reduced as well as power of domestic
warm water heating.
In that case boiler may not be able to reach
desired domestic warm water temperature.

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12
4.2. Use of the boiler
First putting on at the beginning of a season
For the first putting on at the beginning of a central
heating season, the first step should be to put on the
boiler by means of the switch for central heating (5),
temperature in the boiler (1) should be adjusted to
30°C (in this was the heaters are disconnected and
only circulation pump is in operation).
Warm water preparation is put on by means of the
switch for sanitary water (7)
If upon putting on the boiler there is no noise of water
or the central heating if warm water pump does not
run (during operation, the pump produces slight
vibrations) the pump should be manually started.
Circulation pumps lubricate bearings with water
flowing through the pump and after stoppage it could
occur that the bearings “burn”.
Starting the pump (only for IMP GHN pumps)
For starting the pump it is necessary to turn off the
protection plug on its front side (1) below which there
is the axis with the groove for screwdriver. With the
screwdriver, the pump (2) should be several times
turned in direction of the arrow on the pump head and
the boiler should be put on again.
When the pump starts, the operation temperature of
water in boiler and temperature of sanitary water
should be selected. For central heating the optimal
temperature is between 60 and 70°C, whereas for
sanitary water optimal temperature ranges from 45 to
48°C.
If to the boiler a room thermostat is connected, a
desired room temperature should be adjusted
according to the instructions of the producer of room
thermostat.
Segment of control panel

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13
4.3. Manipulation with automatic
equipment
Putting on and of the sanitary water preparation
The boiler is switched on by means of the main switch (7),
for switching on, the switch should be put in the position 1.
Upon switching on a desired water temperature in boiler is
displayed for 5 seconds, signalization of sanitary water
preparation is twinkling (8). Upon 5 seconds real
temperature of sanitary water outlet is displayed (1); if there
is no requirement for sanitary water, the signalization lamp
of sanitary water preparation (8) is switched off.
By switching the switch (7) to the position 0, the sanitary
water preparation is put off. The entered desired
temperature of sanitary water shall be stored.
Adjustment of desired temperature of sanitary water
By pressing the key for temperature adjustment (6) the
desired warm water temperature appears, the signalization
lamp of sanitary water preparation (8) is twinkling. By
repeated pressing upwards or downwards it is possible to
increase or decrease the desired sanitary water
temperature. When the temperature is adjusted it is
sufficient to wait for 5 seconds (signalization lamp of
sanitary water preparation (8) does not twinkle) in order that
the boiler memorizes a new temperature.
Use of sanitary water
If there is a need for sanitary water, the signalization lamp of
sanitary water preparation turns on (8) and the temperature
of warm water outlet displays. Signalization of operation
degree of heaters (2) displays and by turning on lamps it is
shown whether one group of heaters is in operation, two or
all three groups.
The boiler automatically controls a heater operation degree.
Putting on central heating
By switching the switch (5) to the position 1, the central
heating system is switched on. Upon switching on a desired
water temperature in boiler is displayed for 5 seconds,
signalization of boiler operation is twinkling (3). Upon 5
seconds real temperature in the boiler is displayed (1); if the
current temperature in boiler meets the desired one, the
signalization lamp of boiler operation (8) is switched off.
Adjustment of desired temperature of central heating
By pressing the key for temperature adjustment (4) the
desired temperature in the boiler appears, the signalization
lamp of boiler operation (3) is twinkling. By repeated
pressing upwards or downwards it is possible to increase or
decrease the desired sanitary water temperature. When the
temperature is adjusted it is sufficient to wait for 5 seconds
(signalization lamp of boiler operation (8) does not twinkle)
in order that the boiler memorizes a new temperature.
Segment of control panel
Segment of control panel

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14
Parallel operation of central heating and sanitary
water
When both modes of operation are active, central
heating and sanitary water preparation, the boiler
prefers sanitary water.
If there is a requirement for warm water, the boiler
starts with preparation of sanitary water, the lamp (8)
turns on, whereas the boiler operation signalization
turns off (3); temperature indicator (1) displays the
current temperature of warm water outlet.
Air in the boiler “LU” (1)
If in the boiler the air appears, the display will signal
air in the boiler by showing message “LU”, and the
boiler stops the operation. In this way the boiler is
protected against blowing because of appearance of
air. For continuation of operation, the boiler should be
vented. If the boiler is correctly vented, the operation
of boiler continues automatically.
Voltage drop “SP” (1)
If the voltage in the network line drops below 175V by
phase, the display will signal undervoltage protection
by showing message “SP”, the boiler automatically
switches off in order to protect electronics and
contactors inside the boiler. The boiler shall
automatically continue the operation when the
network voltage reaches values above 185V.
Overheating “OH” (1)
If temperature inside the boiler reaches 110°C, and
thermal fuse (10) switch off, boiler stops the operation
until thermal fuse is reset.
The display will signal overheating protection by
showing message “OH”,
Thermal fuse - turning on
By means of thermal fuse (1) the boiler is protected
against rapid increase of temperature above 110°C.
The fuse turns off the boiler and ejects the MCB
(miniature circuit breaker).
For continuation of operation it is necessary to take off
the protection cover from the thermal fuse and press
the white key, upon which the MCB should be
switched on again.
*If the temperature of water inside the boiler exceeds
90°C, the thermal fuse can not be reset. In order to
reset the thermal fuse, it is necessary to wait for the
water temperature to drop below 90°C.
After reseting the thermal fuse, make sure
the MCB iš switched on. The control and
power circuits are separated and the boiler
control can be active if energy part is
disfuncioned.
Segment of the control panel
Segment of the control panel

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15
4.4. Recommendations for optimal use
Central heating
For optimal use of the boiler and electric power
consumption, we recommend the use of quality room
thermostat connected to the boiler.
Daily temperature should be between 20°C i 22°C (for each
degree above 22°C the consumed energy is increasing
exponentially).
For the night operation we recommend temperature
between 15 i 17 °C. In this way energy saving is higher than
in case of complete turning off the boiler during the night.
If there is no room thermostat, for night operation the
temperature in boiler should be decreased to about 40°C or
turned off completely (9. main switch).
In summer period, valves below boiler should not be
closed (closing valves disables water circulation in
system (10 – 15 seconds) generated by safety
thermostat.
Warm water
Optimal temperature of sanitary water, in boiler, is 42°C up
to 45°C (above 48°C it comes to increased lime separation
that sticks to the exchanger, tubes and pump and may lead
to gradual decrease of boiler effect).
5. Maintenance
We recommend the inspection of a device once a year by
the authorized service (before heating season). This service
is not included in the guarantee. During the inspection all
electric and water connections should be tightened, the
system should be vented and – if necessary – filled up,
valves and general functionality of the device should be
checked.
If you notice a reduced effect of warm water it is necessary
to remove lime accumulated within the plate exchanger (1).
Only authorized service engineer can do removing lime.
Prior to the beginning of cleaning, valves (2) separating
the boiler from the sanitary water installation, should be
closed.
Cleaning tubes should be connected to the foreseen 1/2"
piping (3) (internal thread).
Cleaning solution (5) may be formic acid 2-3%, nitric acid 3-
4% or acetic acid 10%.
The solution should circulate through the system by a pump
(4), as long as there is the sludge in the outlet pipe.
Thereupon the direction of a circulation should be changed
and the process repeated.
Upon finished cleaning the boiler should be washed in
the same way with clear water.
For cleaning the product, it is not permitted to use
aggressive media as e.g. gasoline, kerosene or solvent. For
the external shell and decorative cover media for cleaning
plastics or dish washing media may be used. Control panel
should be cleaned with dry or moist cloth (not wet).
Schematic illustration of lime removal

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16
6. Survey of possible defects and irregularities in operation
DEFECT CAUSE ELIMINATION
- at switching on, no voltage on
the control panel
-no feed from net on one or
more phases
-fuse 100mA on the control
panel blown
-there is no control power
-check on serial clamps of
the boiler whether there is
feeding
-replace the fuse 100mA and
check the cause of its
blowing
- at switching on, switches
show voltage on the control
board, but the boiler does not
heat
-check the adjustment of a
room thermostat,
-limit thermostat was
activated,
-indicator of air appearance
in the boiler blocked the
operation,
-defective contactor,
-defective operation
thermostat,
-blown heaters
-check the adjusted
temperature on a room
thermostat, replace its
batteries or it is defective,
-vent the boiler till the lamp
“air in boiler”, turns off
- temperature in boiler is at the
desired value, but the radiators
are not warm
-circulation pump is not in
operation,
-air blockage on central
heating installation, that
prevents the circulation
-start the mechanical pump
or replace it with the new
one if it is blown (see 4.1.),
-vent the installation
- the boiler heats poorly
-on the feed one phase is
missing,
-in two-phase thermostats,
second phase is not in
operation,
-second or third phase was
not manually turned on,
-one contactor defective,
-a part of the heater has
blown,
-in three-phase system to
the boiler are not brought
three various phases
-check fuses on the main
panel,
-replace thermostat or, if
necessary, contactor,
-replace the heater,
-measure with the
instrument voltage between
phases, it should be 400V
- in the operation the contactor
can be heard (it is buzzing) and
possibly radio and TV-
interferences
-poor voltage in the network,
-defective contactor
-select with the instrument
the best phase for control
(on the boiler marked with
“R”)
-replace the contactor
- at switching on or off the
operation thermostat radio and
TV-disturbances
-defective operation
thermostat,
-defective blockade (RC –
protection)
-replace the thermostat,
-replace the RC – member
- boiler in operation is roaring
-a system is not good
vented,
-defective heater
-vent the system,
-replace heaters

We reserve the right of changing these instructions without special prior notification
17
- pressure in heating system is
varying
-defective expansion vessel,
-too low or too high pressure
in the vessel
-if there is water on the valve
for pumping the vessel,
replace the vessel,
-pressure in the vessel
should be 0,5 – 0,8 bar
-RCCB switch is ejecting
-defective heater,
-moist on conductors,
-replace the heater,
-check leaking,
-check the cause of
activation
- MCB cannot be reset
-safety thermostat is activated
-pre-reset safety thermostat
and then the MCB switch
-contact authorized service
personnel to resolve the
exact source of the problem
- sanitary water temperature is
varying
-too low pressure or too
small flow in plumbing
installation
-set the warm water
temperature to the desired
temperature without mixing
with cold water
- boiler does not reach a
desired warm water
temperature
-check network fuses
-warm water flow is higher
than boiler capacity
-check in the instructions the
maximum warm water flow
- boiler does not warm up a
water
-pump for warm water
preparation is not in
operation
-air in warm water system
-start the pump manually
according to the instructions
in 4.1.
-vent the warm water system