Fuel Selector Valve; Fuel Pump Operation - Cirrus SR22 Pilot's Operating Handbook And Flight Manual

Section 7
Systems Description
Drain valves at the system low points allow draining the system for
maintenance and for examination of fuel in the system for
contamination and grade. The fuel must be sampled prior to each
flight. A sampler cup is provided to drain a small amount of fuel from
the wing tank drains, the collector tank drains, and the gascolator
drain. If takeoff weight limitations for the next flight permit, the fuel
tanks should be filled after each flight to prevent condensation.

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
position 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, pressing PRIME will have no
effect. 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
Cirrus Design
SR22
P/N 13772-004
Original Issue