Wall-mounted gas boiler Vaillant
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General information
Ordercode YESSS
7551-8520 
Product code
0010021927
EAN code
4024074807705
Product group
Wall-mounted gas boiler
Brand
Vaillant
Product specifications
Material heat exchanger
Stainless steel
Closed version
Yes
Operation as open model (air supply) possible
Yes
Nominal power, 80-60 °C
20 kW
Nominal power, 50-30 °C
21.6 kW
Burner controller high/low
No
Burner controller, modulating
Yes
Control signal on/off
No
Control signal high/low
No
Control signal 0-10 V
No
Control signal OpenTherm
No
Pilot light
No
Second return connection
No
Max. supply temperature (operating temperature)
80 °C
Built-in filling/drain tap
No
Built-in pump circuit
Yes
Built-in pressure gauge
Yes
Built-in weather-dependent controller
No
Built-in expansion vessel
Yes
Built-in pressure relief valve
Yes
Height
720 mm
Width
440 mm
Depth
338 mm
Connection supply
External thread
Outer pipe diameter supply
26.44 mm
Connection return
External thread
Nominal diameter return
3/4 inch (20)
Outer pipe diameter return
26.44 mm
Connection, fuel
Other
Outer pipe diameter fuel
20 mm
Connection, air supply
Sleeve
Nominal duct width, air supply
100 mm
Connection, flue
Sleeve
Nominal duct diameter, flue
60 mm
Condensate connection
Other
Outer pipe diameter condensate
19 mm
Useful heat emission at nom. heat emission, operation at high temperature (P4)
20.08 kW
Useful efficiency at nominal heat emission, operation at high temperature (n4)
88.67 %
Supplementary electricity consumption at full load (ELmax)
0.07 kW
Supplementary electricity consumption in standby-mode (Psb)
0.002 kW
Condensing
Yes
Connection voltage
230 - 230 V
Frequency
50 Hz
Product information