Cirrus DESIGN SR20 Information Manual page 207

Cirrus Design Section 7
SR20 Airplane Description
mode to deliver a continuous 4-6 psi boost to the fuel flow for vapor
suppression in a hot fuel condition.
Serials 1228 and subs, 1005 thru 1227 after SB 20-73-02: An oil
pressure based system is used to control boost pump operation. The
oil pressure/oil temperature gauge 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 boost 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 boost pump operates on 28 VDC supplied through the 7.5 amp
FUEL PUMP circuit breaker on Main Bus 1.
P/N 13999-002 Info Manual 7-45
September 2011