Viadrus NAOS K4 User manual

VIADRUS K4
Manual for boiler operation and installation
GB_ 2015_31
GB_2017_24

2
Table of Contents page
General Information
1 Produced Versions of the Boilers.............................................................................................................................................................3
2 Boiler Application and Benefits.................................................................................................................................................................3
3 Technical Data.........................................................................................................................................................................................4
4 Boiler Description...................................................................................................................................................................................15
4.1 Boiler Design...................................................................................................................................................................................15
4.2 Control Features..............................................................................................................................................................................15
4.2.1 Removing the front cover...........................................................................................................................................................15
4.3 Main Boiler Parts .............................................................................................................................................................................16
4.4 A diagram showing flue gas flow in the exchanger...........................................................................................................................18
4.5 Delivery and Accessory ...................................................................................................................................................................18
4.6 Instructions before Putting into Operation ........................................................................................................................................18
User
5 Boiler Attendance by the User................................................................................................................................................................19
5.1 Description of the Control.................................................................................................................................................................19
5.2 Modes of Operation .........................................................................................................................................................................19
5.3 Lockout condition codes...................................................................................................................................................................21
5.4 Blocking codes.................................................................................................................................................................................22
5.5 Additional Functions.........................................................................................................................................................................23
5.5.1 LCD symbols test.......................................................................................................................................................................23
5.5.2 Air purge function ......................................................................................................................................................................23
5.6 OpenTherm communication.............................................................................................................................................................23
5.6.1 History information.....................................................................................................................................................................23
5.7 Installer mode..................................................................................................................................................................................24
5.7.1 “tS” as Transparent Parameters mode (TSP).............................................................................................................................24
5.7.2 “In” as Inquiry mode...................................................................................................................................................................24
5.7.3 “Hi” as History mode..................................................................................................................................................................25
5.7.4 “rES” as Reset of the History information...................................................................................................................................25
6 Maintenance ..........................................................................................................................................................................................25
7 IMPORTANT NOTICES.........................................................................................................................................................................26
8 Instructions for Product Disposal After Its Service Life............................................................................................................................26
9 Warranty and Liability for Defects...........................................................................................................................................................27
Servicing
10 Placement and Installation.....................................................................................................................................................................28
10.1 Standards and regulations...............................................................................................................................................................28
10.2 Possible Placement.........................................................................................................................................................................29
10.3 Boiler Installation .............................................................................................................................................................................29
10.4 Connecting to the Heating System and Water Filling........................................................................................................................31
10.5 Gas Connection...............................................................................................................................................................................31
10.6 Electric Power Supply Connection...................................................................................................................................................31
10.7 Condensate Discharge ....................................................................................................................................................................31
10.8 Flue Gas Ducting.............................................................................................................................................................................31
10.9 Boiler Electrical Wiring.....................................................................................................................................................................32
10.9.1 Main components of boiler electrical equipment.........................................................................................................................32
10.9.2 Connection of the higher-level regulation and external boiler sensors........................................................................................32
10.9.3 Connecting terminal...................................................................................................................................................................33
11 Flue Gas Ducting...................................................................................................................................................................................38
11.1 Flue gas ducting – examples of correct connection of flue duct and air supply.................................................................................39
11.2 Flue gas ducting – examples of incorrect connection of flue duct and air supply ..............................................................................39
11.3 STARR D80 and FLEX 80 system connection .................................................................................................................................39
11.3.1 STARR, 2 x D 80 mm flue ducting diagram................................................................................................................................40
11.3.2 FLEX, 2 x D 80 mm flue ducting diagram...................................................................................................................................41
11.4 LIK 60/100, 80/125 system connection ............................................................................................................................................42
11.4.1 Diagram for flue gas ducting of the LIK type, version 60/100 mm (max. length 5 m), or 80/125..................................................43
11.5 Pressure Losses of Chimney Flue Elements in Case of VIADRUS K4 Boiler Usage........................................................................44
12 Commissioning ......................................................................................................................................................................................44
12.1 Instructions before Putting into Operation ........................................................................................................................................45
12.2 Boiler Setting...................................................................................................................................................................................46
12.3 Conversion to a different type of fuel................................................................................................................................................47
12.4 Boiler Electronics Setting.................................................................................................................................................................47
12.4.1 K4GXH24X - Honeywell electronics parameters set in the manufacturing factory (service parameters list neXsys S4962V3224)
..................................................................................................................................................................................................48
12.4.2 K4GXH33X - Honeywell electronics parameters set in the manufacturing factory (service parameters list neXsys S4962V3224)
..................................................................................................................................................................................................49
13 Servicing Inspection of the Boiler...........................................................................................................................................................50

General Information
3
Dear Customer
Thank you for your purchase of the VIADRUS K4 boiler and for your confidence in VIADRUS a.s.
To become familiar with a proper operation of your new product since the beginning, please read carefully the presented user´s manual,
especially Chapter No. 5 – Boiler Attendance by the user, Chapter No. 6 – Maintenance, and Chapter No. 7 – IMPORTANT NOTICES. We ask
you to follow the information presented below and especially to perform the prescribed annual inspections to be performed by an authorized
specialized company, which guarantees a long-term boiler operation free of failures to both your and our satisfaction.
1 Produced Versions of the Boilers
In your order specify the order specification code:
VIADRUS K4 X
1
X
2
X
3
X
4
X
5
X
6
X
1
Exchanger:
G:
stainless Sermeta
X
2
Water heating:
1:
without installed three-way valve with a pump
2: three-way valve, pump, HSW exchanger
3: with a three-way valve with a pump
X
3
Electrical equipment:
H:
Honeywell
X
4
Output:
24:
24 kW
33: 33 kW
X
5
Fuel:
Z:
natural gas
P: propane
X
6
Cover color:
W:
white
R: red
S: silver
B: black
Conversion of the VIADRUS K4 boiler from natural gas to propane and vice-versa can be performed by a contracted service provider
only.
Chimney flue made by ALMEVA has been certified for this boiler. If you use chimney flue made by a different producer, it is necessary
to use a system with identical parameters as for the certified type of the chimney flue.
2 Boiler Application and Benefits
The VIADRUS K4 condensing boiler has been designed for combustion of low pressure natural gas.
The size of the condensing boiler is suitable for heating of family houses and recreational facilities as well as for reconstruction of heat sources
in individual apartment units. The condensation heat output is 5 – 24 kW, 10 – 33 kW.
The boiler body efficiency at the 50/30 °C temperature gradient varies in a range of 101 – 105 % depending on the required output.
Boiler Benefits:
•Low gas consumption
•High combustion efficiency
•Smooth output modulation
•Easy attendance and maintenance
•The boiler enables connecting to a reservoir of hot service water heater and ensures its preferential heating
•Reliability of the regulation and safety components
•Low weight
•Equithermal boiler regulation

General Information
4
3 Technical Data
Tab. . 1 Sizes, operation temperature and electrical variables - VIADRUS K4GXH24XX
K4G1H24ZX
K4G1H24PX
K4G2H24ZX
K4G2H24PX
K4G3H24ZX
K4G3H24PX
Fuel type [-] ZP Propane ZP Propane ZP Propane
Category of appliance [-] I
2H
I
2E
I
3P
I
2H
I
2E
I
3P
I
2H
I
2E
I
3P
Version C
13
,C
33
, C
43
, C
53,
C
83
Weight [kg] 26 27.5 26.5
Water volume [l] 2 3 2
Boiler dimensions – width [mm] 460
– depth [mm] 350
– height [mm] 720
Ø of combustion air connection [mm] 80 / 100 (see fig. no 10)
Ø flue gas socket [mm] 80, 60
Working water overpressure [bar] 3
Testing water overpressure [bar] 5
Pressure loss [-] See diagram 1
Maximum permitted working temperature [°C] 85
Heating water setting range [°C] 25 - 85
Hot water setting range [°C] - 35 - 60 35 - 60
Connecting overpressure of fuel [mbar] 20 37 20 37 20 37
Noise level [dB] < 50
Boiler connection
- heating water output [Js] 3/4“
- heating water input to the heater [Js] - 1/2“ 1/2“
- return heating water input [Js] 3/4“
- return water input from the heater [Js] 1/2“ 3/4“
- system water filling inlet [Js] 1/2" - -
- condensate outlet [mm] Ø 25
- safety valve output [mm] Ø 21,2
- gas inlet [Js] 3/4“
Connecting voltage 1/N/PE 230VAC 50 Hz, TN-S
El. power input including pump [W] 110
El. covering IP 40
Tab. . 2 Thermal – technical parameters - VIADRUS K4GXH24XX
comparison conditions 15 °C and 101.325 kPa, dry gas
K4G1H24ZX
K4G1H24PX
K4G2H24ZX
K4G2H24PX
K4G3H24ZX
K4G3H24PX
Boiler output range [kW] 5 - 24
Nominal output 80/60 °C [kW] 22,2
Nominal output 50/30 °C [kW] P=24
Minimum output 50/30 °C [kW] P=5
Maximum nominal heat input [kW] Q=22.8
Minimum nominal heat input [kW] Q=4.6
DHW flow with ∆T [l.min
-
1
] - See diagram 2 -
Boiler efficiency at the nominal output 80/60°C [%] Up to 98
Boiler efficiency at the nominal output 50/30°C [%] Up to 105
Volume flow rate of fuel [m
3
.h
-
1
] 0.5-2.4 0.2-0.9 0.5-2.4 0.2-0.9 0.5-2.4 0.2-0.9
Mass flow rate of flue gas [kg.h
-
1
] 8 - 45
Nox class [-] 5
Flue gas temperature (max.) [°C] 85

General Information
5
Tab. . 3 Sizes, operation temperature and electrical variables - VIADRUS K4GXH33XX
K4G1H33ZX
K4G1H33PX
K4G2H33ZX
K4G2H33PX
K4G3H33ZX
K4G3H33PX
Fuel type [-] ZP Propane ZP Propane ZP Propane
Category of appliance [-] I
2H
I
2E
I
3P
I
2H
I
2E
I
3P
I
2H
I
2E
I
3P
Version C
13
,C
33
, C
43
, C
53,
C
83
Weight [kg] 28 29,5 28,5
Water volume [l] 3 4 3
Boiler dimensions – width [mm] 460
– depth [mm] 350
– height [mm] 720
Ø of combustion air connection [mm] 80 / 100
Ø flue gas socket [mm] 80, 60 (see fig. no 10)
Working water overpressure [bar] 3
Testing water overpressure [bar] 5
Pressure loss [-] See diagram 1
Maximum permitted working temperature [°C] 85
Heating water setting range [°C] 25 - 85
Hot water setting range [°C] - 35 - 60 35 - 60
Connecting overpressure of fuel [mbar] 20 37 20 37 20 37
Noise level [dB] < 50
Boiler connection
- heating water output [Js] 3/4“
- heating water input to the heater [Js] - 1/2“ 1/2“
- return heating water input [Js] 3/4“
- return water input from the heater [Js] 1/2“ 3/4“
- system water filling inlet [Js] 1/2" - -
- condensate outlet [mm] Ø 25
- safety valve output [mm] Ø 21,2
- gas inlet [Js] 3/4“
Connecting voltage 1/N/PE 230VAC 50 Hz, TN-S
El. power input including pump [W] 110
El. covering IP 40
Tab. . 4 Thermal – technical parameters - VIADRUS K4GXH33XX
comparison conditions 15 °C and 101.325 kPa, dry gas
K4G1H33ZX
K4G1H33PX
K4G2H33ZX
K4G2H33PX
K4G3H33ZX
K4G3H33PX
Boiler output range [kW] 6,5 - 33
Nominal output 80/60 °C [kW] P=30,5
Nominal output 50/30 °C [kW] P=33
Minimum output 50/30 °C [kW] P=6,5
Maximum nominal heat input [kW] Q=31,4
Minimum nominal heat input [kW] Q=6,3
DHW flow with ∆T [l.min
-
1
] - See diagram 3 -
Boiler efficiency at the nominal output 80/60°C [%] Up to 98
Boiler efficiency at the nominal output 50/30°C [%] Up to 105
Volume flow rate of fuel [m
3
.h
-
1
] 0,68-3,3 0,28-1,28 0,68-3,3 0,28-1,28 0,68-3,3 0,28-,28
Mass flow rate of flue gas [kg.h
-
1
] 11 - 62
Nox class [-] 5
Flue gas temperature (max.) [°C] 85

General Information
6
Diagram no. 1 A diagram of the boiler heating circuit hydraulic loss
Fig. . 1 The main boiler dimensions

General Information
7
4,50
6,50
8,50
10,50
12,50
14,50
16,50
2,50 3,50 4,50 5,50 6,50 7,50 8,50 9,50
Výkon kotle (kW)
Průtok TV (l/min)
K4G2H24.. Ohřev TV -  T 25 C
4,00
9,00
14,00
19,00
24,00
2,00 3,00 4,00 5,00 6,00 7,00 8,00 9,00 10,00 11,00
Výkon kotle (kW)
Průtok TV (l/min)
K4G2H24.. Ohřev TV -  T=30 C
7,00
9,00
11,00
13,00
15,00
17,00
19,00
21,00
23,00
2,50 3,50 4,50 5,50 6,50 7,50 8,50 9,50
Výkon kotle (kW)
Průtok TV (l/min)
K4G2H24.. Ohřev TV -  T 35 C
Graph No. 2 Dependence of boiler power on flow rate of heated hot water (version VIADRUS K4G2H24XX)
K4G2H24.. Hot water heating - T 25 °C
K4G2H24.. Hot water heating - T 30 °C
K4G2H24.. Hot water heating - T 35 °C
Boiler power
(kW)
Boiler power
(kW)
Boiler power
(kW)
Hot water flow rate (l/min)
Hot water flow rate (l/min)
Hot water flow rate (l/min)

General Information
8
4,00
9,00
14,00
19,00
24,00
3,00 5,00 7,00 9,00 11,00 13,00 15,00
Výkon kotle (kW)
Průtok TV (l/min )
K4G2H33.. Ohřev TV -T 35 C
4,00
9,00
14,00
19,00
24,00
29,00
34,00
2,00 4,00 6,00 8,00 10,00 12,00 14,00 16,00
Výkon kotle (kW)
Průtok TV (l/min)
K4G2H33.. Ohřev TV -  T 30 C
4,00
9,00
14,00
19,00
24,00
29,00
34,00
3,00 5,00 7,00 9,00 11,00 13,00
Výkon kotle (kW)
Průtok TV (l/min )
K4G2H33.. Ohřev TV -  T 35 C
Graph No. 3 Dependence of boiler power on flow rate of heated hot water (version VIADRUS K4G2H33XX)
K4G2H33.. Hot water heating - T 25 °C
K4G2H33.. Hot water heating - T 30 °C
K4G2H33.. Hot water heating - T 35 °C
Boiler power
(kW)
Boiler power
(kW)
Boiler power
(kW)
Hot water flow rate (l/min)
Hot water flow rate (l/min)
Hot water flow rate (l/min)

General Information
9
Information requirements for boiler space heaters, boiler combination heaters
and cogeneration space heaters
Model(s): VIADRUS K4G1H24XX
Condensing boiler: yes
Low-temperature (**) boiler: no
B1 boiler: no
Cogeneration space heater: no If yes, equipped with a supplementary heater:
Combination heater: no
Item
Symbol
Value
Unit
Item
Symbol
Value
Unit
Rated heat output Prated 24 kW
Seasonal space heating energy
efficiency ƞ
s
90 %
For boiler space heaters and boiler combination heaters: Useful
heat output For boiler space heaters and boiler combination heaters: Useful efficiency
At rated heat output and high-
temperature regime (*) P
4
24 kW At rated heat output and high-
temperature regime (*) ƞ
4
97,53 %
At 30 % of rated heat output and
low-temperature regime (**) P
1
4 kW At 30 % of rated heat output and low-
temperature regime (**) ƞ
1
105,72 %
Auxiliary electricity consumption Other items
At full load el
max
0,02 kW Standby heat loss P
stby
0,045 kW
At part load el
min
0,011 kW Ignition burner power consumption P
ign
- kW
In standby mode P
SB
0,003 kW Emissions of nitrogen oxides NO
x
25 mg/
kWh
Contact details VIADRUS a.s.
Bezručova 300
Bohumín
735 81
Czech Republic
(*) High-temperature regime means 60 °C return temperature at heater inlet and 80 °C feed temperature at heater outlet.
(**) Low temperature means for condensing boilers 30 °C, for low-temperature boilers 37 °C and for other heaters 50 °C return
temperature (at heater inlet).

General Information
10
Information requirements for boiler space heaters, boiler combination heaters
and cogeneration space heaters
Model(s): VIADRUS K4G2H24XX
Condensing boiler: yes
Low-temperature (**) boiler: no
B1 boiler: no
Cogeneration space heater: no If yes, equipped with a supplementary heater:
Combination heater: yes
Item
Symbol
Value
Unit
Item
Symbol
Value
Unit
Rated heat output Prated 24 kW
Seasonal space heating energy
efficiency ƞ
s
90 %
For boiler space heaters and boiler combination heaters: Useful
heat output For boiler space heaters and boiler combination heaters: Useful efficiency
At rated heat output and high-
temperature regime (*) P
4
24 kW At rated heat output and high-
temperature regime (*) ƞ
4
97,53 %
At 30 % of rated heat output and
low-temperature regime (**) P
1
4 kW At 30 % of rated heat output and low-
temperature regime (**) ƞ
1
105,72 %
Auxiliary electricity consumption Other items
At full load el
max
0,02 kW Standby heat loss P
stby
0,045 kW
At part load el
min
0,011 kW Ignition burner power consumption P
ign
- kW
In standby mode P
SB
0,003 kW Emissions of nitrogen oxides NO
x
25 mg/
kWh
For combination heaters:
Declared load profile XL Water heating energy efficiency ƞ
wh
84 %
Daily electricity consumption Q
elec
0,204 kWh Daily fuel consumption Q
fuel
23,215 kWh
Contact details VIADRUS a.s.
Bezručova 300
Bohumín
735 81
Czech Republic
(*) High-temperature regime means 60 °C return temperature at heater inlet and 80 °C feed temperature at heater outlet.
(**) Low temperature means for condensing boilers 30 °C, for low-temperature boilers 37 °C and for other heaters 50 °C return
temperature (at heater inlet).

General Information
11
Information requirements for boiler space heaters, boiler combination heaters
and cogeneration space heaters
Model(s): VIADRUS K4G3H24XX
Condensing boiler: yes
Low-temperature (**) boiler: no
B1 boiler: no
Cogeneration space heater: no If yes, equipped with a supplementary heater:
Combination heater: yes
Item
Symbol
Value
Unit
Item
Symbol
Value
Unit
Rated heat output Prated 24 kW
Seasonal space heating energy
efficiency ƞ
s
90 %
For boiler space heaters and boiler combination heaters: Useful
heat output For boiler space heaters and boiler combination heaters: Useful efficiency
At rated heat output and high-
temperature regime (*) P
4
24 kW At rated heat output and high-
temperature regime (*) ƞ
4
97,53 %
At 30 % of rated heat output and
low-temperature regime (**) P
1
4 kW At 30 % of rated heat output and low-
temperature regime (**) ƞ
1
105,72 %
Auxiliary electricity consumption Other items
At full load el
max
0,02 kW Standby heat loss P
stby
0,045 kW
At part load el
min
0,011 kW Ignition burner power consumption P
ign
- kW
In standby mode P
SB
0,003 kW Emissions of nitrogen oxides NO
x
25 mg/
kWh
For combination heaters:
Declared load profile XL Water heating energy efficiency ƞ
wh
81 %
Daily electricity consumption Q
elec
0,222 kWh Daily fuel consumption Q
fuel
24,301 kWh
Contact details VIADRUS a.s.
Bezručova 300
Bohumín
735 81
Czech Republic
(*) High-temperature regime means 60 °C return temperature at heater inlet and 80 °C feed temperature at heater outlet.
(**) Low temperature means for condensing boilers 30 °C, for low-temperature boilers 37 °C and for other heaters 50 °C return
temperature (at heater inlet).

General Information
12
Information requirements for boiler space heaters, boiler combination heaters
and cogeneration space heaters
Model(s): VIADRUS K4G1H33XX
Condensing boiler: yes
Low-temperature (**) boiler: no
B1 boiler: no
Cogeneration space heater: no If yes, equipped with a supplementary heater:
Combination heater: no
Item
Symbol
Value
Unit
Item
Symbol
Value
Unit
Rated heat output Prated 33 kW
Seasonal space h
eating energy
efficiency ƞ
s
90 %
For boiler space heaters and boiler combination heaters: Useful
heat output For boiler space heaters and boiler combination heaters: Useful efficiency
At rated heat output and high-
temperature regime (*) P
4
30,3 kW At rated heat output and high-
temperature regime (*) ƞ
4
98,4 %
At 30 % of rated heat output and
low-temperature regime (**) P
1
6 kW At 30 % of rated heat output and low-
temperature regime (**) ƞ
1
104,8 %
Auxiliary electricity consumption Other items
At full load el
max
0,11 kW Standby heat loss P
stby
0,044 kW
At part load el
min
0,04 kW Ignition burner power consumption P
ign
- kW
In standby mode P
SB
0,003 kW Emissions of nitrogen oxides NO
x
26 mg/
kWh
Contact details VIADRUS a.s.
Bezručova 300
Bohumín
735 81
Czech Republic
(*) High-temperature regime means 60 °C return temperature at heater inlet and 80 °C feed temperature at heater outlet.
(**) Low temperature means for condensing boilers 30 °C, for low-temperature boilers 37 °C and for other heaters 50 °C return
temperature (at heater inlet).

General Information
13
Information requirements for boiler space heaters, boiler combination heaters
and cogeneration space heaters
Model(s): VIADRUS K4G2H33XX
Condensing boiler: yes
Low-temperature (**) boiler: no
B1 boiler: no
Cogeneration space heater: no If yes, equipped with a supplementary heater:
Combination heater: yes
Item
Symbol
Value
Unit
Item
Symbol
Value
Unit
Rated heat output Prated 33 kW
Seasonal space heating energy
efficiency ƞ
s
90 %
For boiler space heaters and boiler combination heaters: Useful
heat output For boiler space heaters and boiler combination heaters: Useful efficiency
At rated heat output and high-
temperature regime (*) P
4
30,3 kW At rated heat output and high-
temperature regime (*) ƞ
4
98,4 %
At 30 % of rated heat output and
low-temperature regime (**) P
1
6 kW At 30 % of rated heat output and low-
temperature regime (**) ƞ
1
104,8 %
Auxiliary electricity consumption Other items
At full load el
max
0,11 kW Standby heat loss P
stby
0,044 kW
At part load el
min
0,04 kW Ignition burner power consumption P
ign
- kW
In standby mode P
SB
0,003 kW Emissions of nitrogen oxides NO
x
26 mg/
kWh
For combination heaters:
Declared load profile XL Water heating energy efficiency ƞ
wh
86 %
Daily electricity consumption Q
elec
0,180 kWh Daily fuel consumption Q
fuel
22,66 kWh
Contact details VIADRUS a.s.
Bezručova 300
Bohumín
735 81
Czech Republic
(*) High-temperature regime means 60 °C return temperature at heater inlet and 80 °C feed temperature at heater outlet.
(**) Low temperature means for condensing boilers 30 °C, for low-temperature boilers 37 °C and for other heaters 50 °C return
temperature (at heater inlet).

General Information
14
Information requirements for boiler space heaters, boiler combination heaters
and cogeneration space heaters
Model(s): VIADRUS K4G3H33XX
Condensing boiler: yes
Low-temperature (**) boiler: no
B1 boiler: no
Cogeneration space heater: no If yes, equipped with a supplementary heater:
Combination heater: yes
Item
Symbol
Value
Unit
Item
Symbol
Value
Unit
Rated heat output Prated 33 kW
Seasonal space heating energy
efficiency ƞ
s
90 %
For boiler space heaters and boiler combination heaters: Useful
heat output For boiler space heaters and boiler combination heaters: Useful efficiency
At rated heat output and high-
temperature regime (*) P
4
30,3 kW At rated heat output and high-
temperature regime (*) ƞ
4
98,4 %
At 30 % of rated heat output and
low-temperature regime (**) P
1
6 kW At 30 % of rated heat output and low-
temperature regime (**) ƞ
1
104,8 %
Auxiliary electricity consumption Other items
At full load el
max
0,11 kW Standby heat loss P
stby
0,044 kW
At part load el
min
0,04 kW Ignition burner power consumption P
ign
- kW
In standby mode P
SB
0,003 kW Emissions of nitrogen oxides NO
x
26 mg/
kWh
For combination heaters:
Declared load profile XL Water heating energy efficiency ƞ
wh
77 %
Daily electricity consumption Q
elec
0,190 kWh Daily fuel consumption Q
fuel
25,742 kWh
Contact details VIADRUS a.s.
Bezručova 300
Bohumín
735 81
Czech Republic
(*) High-temperature regime means 60 °C return temperature at heater inlet and 80 °C feed temperature at heater outlet.
(**) Low temperature means for condensing boilers 30 °C, for low-temperature boilers 37 °C and for other heaters 50 °C return
temperature (at heater inlet).

General Information
15
4 Boiler Description
4.1 Boiler Design
The boiler elementary structure consists in a condensing exchanger made of stainless steel pipes. It is checked for tightness by test
overpressure 5 bar. The boiler is further equipped with a premix burner. The combustion mixture is mixed in a mixer in the preset air-gas ratio
within the entire output range. Air is supplied to the mixer by a modulation fan.
The boiler is made in three versions:
VIADRUS K4G1HXXXX version designed for heating only is equipped with a circulation pump
VIADRUS K4G2HXXXX version with a circulation pump and flow type hot water (hereafter referred to as “DHW”) heater
VIADRUS K4G3HXXXX version with a circulation pump and a three-way valve ready to be used in combination with a reservoir type hot
water heater
The Honeywell automatics is an electronic control and ignition automatics designed for gas-fired central heating boilers with a modulated fan
and burner with preliminary mixing.
The combustion air inlet and the flue gas outlet may be implemented by several means as follows:
- to the chimney,
- through the wall,
- through the roof (either inclined or horizontal),
- to a joint shaft.
The boiler is an appliance in version C, i.e., a closed appliance with electronic ignition and flame ionization.
4.2 Control Features
Fig. . 2 The VIADRUS K4 boiler control panel
4.2.1 Removing the front cover
•Remove the bolts (1)
•
Pulling the cover side detach
the Velcro strip (2) •Remove the front cover
Fig. . 3 Removing the boiler front cover
1 electronic panel with the control panel
2 pressure gauge
3 valve for adding water to the heating system

General Information
16
4.3 Main Boiler Parts
Fig. . 4 The VIADRUS K4 boiler assembly (version shown - K4G2HXXXX)
1 three-way valve (only for versions K4G2HXXXX and K4G3HXXXX)
2 HSW temperature sensor (only for version K4G2HXXXX)
3 HSW exchanger (only for version K4G2HXXXX)
4 gas valve
5 siphon
6 safety valve
7 circulation pump
8 gas supply pipe
9 bleeder valve
10 boiler electronics
11 burner plate
12 heating water temperature sensor
13 mixer
14 safety thermostat
15 combination electrode
16 boiler frame
17 exchanger
18 fan
19 expansion tank
20 pressure gauge
21 boiler front cover

General Information
17
1 condensing exchanger
2 input of return water to the exchanger
3 pump
4 input of return water to the pump
5 heating system (radiators)
6 output of hot water from the exchanger
7 input of hot water to the radiators
8 filling valve
9 pressure relief valve
Fig. . 5 VIADRUS K4G1HXXXX with only water heating for the system
(hydraulic diagram of the version and the sketch of the hydro-block)
1 condensing exchanger
2 input of return water to the exchanger
3 pump
4 input of return water to the pump
5 heating system (radiators)
6 output of hot water from the exchanger
7 input of hot water to the radiators
8 three-way valve
9 flow type water heater
10 input of water to the flow type water heater
11 output of water from the flow type water heater
12 pressure relief valve
Fig. . 6 VIADRUS K4G2HXXXX with a flow type heater
(hydraulic diagram of the version and the sketch of the hydro-block)
1 condensing exchanger
2 input of return water to the exchanger
3 pump
4 input of return water to the pump
5 heating system (radiators)
6 output of hot water from the exchanger
7 input of hot water to the radiators
8 three-way valve
9 filling valve
10 output of hot water from the heater
11 refilling of water to the system
12 reservoir type water heater
13 relief valve of the heater
14 input of water to the heater
15 pressure relief valve
Fig. . 7 VIADRUS K4G3HXXXX the boiler version
(hydraulic diagram of the version and the sketch of the hydro-block)

General Information
18
4.4 A diagram showing flue gas flow in the exchanger
Fig. . 8 A diagram showing flue gas flow in the exchanger
4.5 Delivery and Accessory
The VIADRUS K4 boiler is delivered as assembled on a pallet, packed in a carton cover. Flue gas ducting is delivered in accordance with the
customer requirements based on the actual connection of air inlet and flue gas outlet (see chapter 11).
Standard accessory for all boiler versions:
Mounting bracket 1 pc
Dowel - 8 x 40 mm 5 pcs
Bolt - 5 x 40 5 pcs
Chimney opening reducer piece 1 pcs
External sensor 1 pc
Screening (for changing-over to propane) 1 pc
Blinding plug D80 1 pc
Operation and installation manual, including the warranty certificate
For version VIADRUS K4G3HXXXX:
sensor QAZ 36.526/109 1 pc
Recommended accessory for all boiler versions:
Room thermostat 1 pc
ALMEVA flue gas ducting, Type: LIK, STAR or FLEX
Water filter
Opentherm (Honeywell CR 04 or CR 05)
The recommended accessory is not included in the boiler standard price.
4.6 Instructions before Putting into Operation
The boiler can only be commissioned by organizations that are authorized and trained for this purpose by the manufacturer.
The installation shall comply with the regulations that are applicable for this equipment. The boiler shall be compatible with the local connecting
conditions (checking the parameters of the boiler with the information on the name plate).
During the first start of operation of the boiler it is necessary to instruct the user in accordance with this manual and to hand over this
manual to the user.
Then it is necessary to perform:
- inspection revision before commissioning,
- inspection for any water leakages,
- inspection of instrumentation and safety controls.
Notice: The ABS boiler cover is protected by a protection foil. This foil needs to be removed before commissioning of the boiler or 1 month
from unpacking the boiler from the packaging carton at the latest. Removing the foil after this period may be more difficult.
first heat exchange
water output 50°C
water input
30°C
flue gas after water
condensation
condensation partition
condensate outlet
water output
water input
condensate
gorce spaliny gazuhot flue gas
flue gas after the first hea
t exchange
flue gas after the second heat exchange
burner
40 °C

User
19
5 Boiler Attendance by the User
Description of the control panel
5.1 Description of the Control
The basic information shown on the screen is represented by the heating circuit temperature – in case of DHW heating it is the temperature
measured by the DHW sensor.
Setting of the desired DHW temperature of the system is achieved by pushbuttons
K6
and
K7
. Setting of the desired DHW temperature
of the system is achieved by pushbuttons
K1
and
K2
on the boiler control panel.
In case of using higher-level control, this option is blocked on the boiler and temperatures can be set only from the room device.
Switching between the SUMMER/WINTER operation and turning OFF is done by
K5
pushbutton.
The basic information will be shown after pressing
i
K3
pushbutton.
Defects are reset by
reset
K4
pushbutton.
After turning OFF, the boiler is still energized and the control unit ensures antifreeze protection and if selected then also regular short operation
of the pump to prevent stiffening.
5.2 Modes of Operation
The controller has a number of operation modes:
• OFF mode, heat demands are ignored except for CH and
DHW frost protection calling
• STAND-BY
• CH mode
• DHW mode
• TEST or INSTALLER MODE, option for the installer to test
and set boiler parameters
• ERROR/FAULT conditions like high temperature, lockout,
sensor fault, etc.
The priority of operating modes is fixed as follows:
1. Error/fault mode
2. Test or Installer mode
3. DHW mode
4. CH mode
5. Stand-by mode
6. OFF mode
In case of normal operation in DHW or CH mode and no error conditions it is always possible to enter the test mode as the higher priority mode
of operation. This implies that there are no error conditions present. If there was an error condition, test mode can be entered after normal
operating conditions are present again.
OFF mode
This is mode is selected by mean of the
K5
push button.
When selected, LCD is indicating:
K1 CH setpoint adjustment (+)
K2 CH setpoint adjustment (-)
K3 Info mode selection
K4 RESET mode
K5 OFF / DHW / CH+DHW modes enabling
K6 DHW setpoint adjustment (-)
K7 DHW setpoint adjustment (+)
DG1 7 segments digit
DG2 7 segments digit
DG3 7 segments digit
S1 DHW mode
S2 reset request
S3 dot
S4 CH mode
S5 centigrade degree
S6-S7-S8 burner power indication
S9 solar mode
S10 .. S17 water pressure level indication (x.x resolution)
S18 service request

User
20
STAND-BY mode
By mean of
K5
push button it possible to select boiler STAND-BY modes selecting Winter (both DHW and CH
modes are enable) or Summer (only DHW mode is enable) working conditions.
When Winter is selected, an no head demand is present, LCD is indicating:
When Summer is selected, an no head demand is present, LCD is indicating:
In case of water pressure switch usage, Supply temperature value is shown rather than water pressure value/indication (scale).
In STAND-BY mode the fan is off, the gas valve is closed, Supply pump is switched off and the 3WV is in DHW position.
Presetting CH supply temperature
Operate
K2
(decrease) and
K1
(increase) pushbuttons to select CH supply temperature within 20°C and CH
user set point maximum value. This value is called CH user set point.
When
K2
or
K1
is operated, the LCD displays the temperature setting in 1°C steps in flashing mode:
5 sec. since last acting on K
K2
2 or
K1
has been made, LCD come back to the previous display condition.
Presetting DHW temperature
Operate
K6
(decrease) and
K7
(increase) pushbuttons to select DHW temperature within 30°C and DHW
user set point maximum value. This value is called DHW user set point.
When
K6
or
K7
is operated, the LCD displays the temperature setting in 1°C steps in flashing mode:
5 sec. since last acting on
K6
or
K7
has been made, LCD come back to the previous display condition.
Burner ignition
In case of valid heat demand request, ignition sequence will be started. In case of failed ignition, controller will try to reignite for a defined
number of times. At the first ignition trial, the burner will ignite with fan speed set by Ignition fan speed value. As soon as the flame presence is
validated, fan speed moves according to the heat demand type. If no successful ignition after programmed number of retrials, flame lockout
error will be indicated.
CH mode
Operation in the CH mode is possible only when Winter is enabled.
CH heat demand can be generated by Room Thermostat SELV input or by OpenTherm control unit. If remote control is connected and
communication is validated, room thermostat input is ignored.
ON/OFF control (no OTC – no OpenTherm room unit)
Closure of Room Thermostat contact generates an heat demand in CH mode.
Supply pump is switched on.
Flame indication is showing:
HD + Flame ON + power < 30%
HD + Flame ON + power > 30% <75%
HD + Flame ON + power > 75%
If a higher priority operating demand is received, the function in progress is stopped to meet this demand.
ON/OFF control (OTC – no OpenTherm room unit)
Outdoor temperature sensor must be connected to the controller.