Fuel Selector Valve; Fuel Pump Operation - Cirrus SR22 Pilot Operating Handbook

S 7: A
ECTION IRPLANE AND
F S
UEL YSTEM

Fuel Selector Valve

A fuel selector valve, located at the rear of the center console, provides the
following functions:
• LEFT Allows fuel to flow from the left tank
• RIGHT Allows fuel to flow from the right tank
• OFF Cuts off fuel flow from both tanks
The valve is arranged so that to feed off a particular tank, the valve should
be pointed to the fuel indicator for that tank. To select RIGHT or LEFT,
rotate the selector to the desired position. To select Off, first raise the fuel
selector knob release and then rotate the knob to OFF.

Fuel Pump Operation

Fuel pump operation and engine prime is controlled through the Fuel
Pump switch located adjacent to the fuel selector valve. The PRIME posi-
tion is momentary and the BOOST position is selectable. A two-speed
prime allows the fuel pressure to rapidly achieve proper starting pressure.
An oil pressure based system is used to control fuel pump operation. The
oil pressure/oil temperature sensor provides a signal to the starting circuit
to generate a ground for the oil annunciator and the fuel system. This
system allows the fuel pump to run at high speed (PRIME) when the engine
oil pressure is less than 10 PSI. Whenever the engine oil pressure exceeds
10 PSI, the PRIME functionality of the Fuel Pump is disabled. This is done
to prevent high speed operation while the engine is running. If PRIME is
selected on the fuel pump switch while oil pressure exceeds 10 PSI, the Fuel
Pump operates in BOOST mode. Selecting BOOST energizes the fuel pump
in low-speed mode regardless of oil pressure to deliver a continuous 4-6 psi
boost to the fuel flow for vapor suppression in a hot fuel condition.
The fuel pump operates on 28 VDC supplied through the 5-amp FUEL
PUMP circuit breaker on MAIN BUS 2.
7-40
S
YSTEMS
C D
IRRUS ESIGN
SR22
P/N 13772-006
Reissue A