Cast iron boiler for wood Viadrus U22 Economy

Wooden cast iron boiler Viadrus U22 Economy

Viadrus U22 Economy is a pyrolytic cast iron boiler with manual loading of fuel for ecological wood burning. The boiler can operate in gravitational heating systems without the use of a pump. Combustion chamber has been designed in such a way as to enable fuel combustion with natural exhaust extraction without the use of a fan.

10-year warranty on the cast iron body
threaded ferrules for easy installation
Effectiveness up to 91%
meets the conditions of 'Ekodesign'
meets the requirements of emission class 5 according to ČSN 303-5
large heat extraction from the flue gas ducts
meets the strict requirements of the German emission standard BlmSchV Stufe 2

low fuel consumption
easy to operate and maintain
patented ViaBurn combustion chamber system
low exhaust temperature (approx. 140 - 180 °C)
operation without electrical power supply (without forced exhaust gas extraction and without circulation pump, except for systems with buffer tank)

Boiler Size/Type	S.I	16	21	25	30	34	38	41
Energy class	•	A+	A+	A+	A+	A+	A+	A+
Nominal Power	kW	16	21	25	30	34	38	41
Effciency	%	89,1	89	89	88,7	91	90,4	90,3
Boiler class	[-]	5
ECODESIGN	[-]	+
Combustion chamber depth	mm	280	370	370	480	590	590	590
Recomended length of wood pieces	mm	350				350-500
Combustion chamber volume	dm³	32	39	41	51	63	65	67
Approximate fuel consumption at nominal power	kg/h	3,9	5,1	5,9	7,2	8,5	9,4	10,2
Temperature of exhaust gases at nominal power	ºC	140-190
Sizes - Height × Width	mm	1130 x 625
- Depth (A)	mm	890	1000	1000	1110	1220	1220	1220
Boiler weight	kg	348	410	410	472	534	534	534
Dimensions of the loading bay	mm	310x236
Required chimney draught	Pa	13	16	18	21	25	32	32
Water capacity	l	40,5	46,5	46,5	52	58	58	58
Recommended minimum outlet water temperature	ºC	70
Minimum return flow temperature	ºC	50
Connection of heating water / return water	-	2 lub 6/4"
Noise emission level	dB	do 65
Diameter of the flue pipe	mm	156
Maximum pressure	bar	4
Minimum working pressure of water	bar	1,5
Flue gas mass flow	kg/s	0,012	0,014	0,015	0,016	0,018	0,019	0,022

Boiler Dimensions

Boiler size / Type	-	16	21	25	30	34	38	41
Length A	mm	890	1000	1000	1110	1220	1220	1220
Length B	mm	620	730	730	840	950	950	950

The manufacturer recommends installing the boiler in combination with a buffer tank. The dimensions of the buffer tank must be determined according to the boiler power. We have to count on the maximum calculated capacity, the minimum buffer tank volume used must be 300 l.

Loading door choke
Slanting grate (size varies according to boiler type)
Slanting grate (size varies according to boiler type)
Slanting grate (size varies according to boiler type)
Short-circuit flap
Cover for cleaning the flue gas spigot
Top fitting, front
Upper rear adapter
Tertiary air inlet nozzle
Lower left-hand fitting with secondary air supply
Right-hand bottom fitting with secondary air supply
Secondary and tertiary air inlet chamber

Data sheet

Power [ kW ]	25
Power [ kW ]	38
Power [ kW ]	16
Power [ kW ]	34
Power [ kW ]	21
Power [ kW ]	30
Power [ kW ]	41
Efficiency [ % ]	90.3
Efficiency [ % ]	89.1
Efficiency [ % ]	90.4
Efficiency [ % ]	91
Efficiency [ % ]	89
Efficiency [ % ]	88.7
Efficiency [ % ]	89
Weight [ kg ]	472
Weight [ kg ]	410
Weight [ kg ]	534
Weight [ kg ]	410
Weight [ kg ]	534
Weight [ kg ]	348
Weight [ kg ]	534
Depth [ mm ]	1,110
Depth [ mm ]	1,000
Depth [ mm ]	1,220
Depth [ mm ]	1,000
Depth [ mm ]	1,220
Depth [ mm ]	1,220
Depth [ mm ]	890
Water capacity [ L ]	52
Water capacity [ L ]	46.5
Water capacity [ L ]	58
Water capacity [ L ]	58
Water capacity [ L ]	46.5
Water capacity [ L ]	58
Water capacity [ L ]	40.5
EcoDesign	YES
Class	5
Height [ mm ]	1,130
Width [ mm ]	625
Installation	Vertical, Floor, Internal
Max. operating pressure [ bar ]	1.500
Fuel	wood