Fuel Supply; Air/Gas Mixer - Riello 20047690 Installation, Use And Maintenance Instructions

4.8

Fuel supply

Explosion danger due to fuel leaks in the presence
of a flammable source.
Precautions: avoid knocking, attrition, sparks and
heat.
Make sure that the fuel interception tap is closed
before performing any operation on the burner.
The fuel supply line must be installed by qualified
personnel, in compliance with current standards
and laws.
WARNING
The burners are teamed with one-piece pneumatic proportioning
gas valves, via which the amount of gas delivered, and hence the
output produced, can be modulated.
A signal reporting pressure detected in the air circuit is carried to
the pneumatic gas valve, which delivers an amount of gas in pro-
portion to the airflow produced by the fan.
Upstream gas pressure
test point (P1)
Electrical valve
connection (XV1)
Minimum gas flow
adjustment on the
stabiliser (V2)
Compensation
pipe (T)
Gas valve
Fair lead
Installation
4.8.1

Air/gas mixer

Gas and combustive air are mixed inside the purging circuit (mix-
er), starting from the intake inlet.
Through the gas train, fuel is introduced into the intake air current
and optimal mixing commences with the aid of a mixer.
Pipe (T) between valve-Venturi allows compensa-
tion to occur for accidental occlusion of the suction
line due to a reduction in gas delivered.
CAUTION
After having connected the compensation pipe (T) with the valve,
cover it again with the rubber protective device.
Adjustment of maximum
gas flow (V1)
Fair lead
Metallic protective
device
21 GB
Air/Gas mixer (Venturi)
in the suction line circuit
Downstream pressure test point (P2)
20056648
Compensation
pipe (T)
Fig. 15
20051011