Fig. 7: Diagram of B-6 Feed Valve, Open.
Main reservoir pressure then forces the supply piston and valve over into open position, as shown in Fig. 7, and allows a further flow of air through port "c" to the feed valve pipe to again raise its pressure to the adjustment of the feed valve, when the valve will again close.
102. Q. What is the duty of the feed valve?
A. To control and maintain a constant pressure in the brake pipe when the brake valve is in running or holding position.
103. Q. What defect in the feed valve will cause the brake pipe pressure to equalize with that in the main reservoir?
A. This may be caused by a defective feed valve case gasket, permitting main reservoir air to leak into the feed valve pipe, or leakage past the supply valve, or the regulating valve held from its seat, or the supply valve piston too tight a fit in its cylinder.
104. Q. If the brake pipe charges too slowly when nearing the maximum pressure, where is the trouble?
A. This may be caused by a loose-fitting supply valve piston 8, or the port past the regulating valve 12 partly stopped up.