c. Tighten the packing nut.
d. Turn the stem clockwise until the leak stops.
e. Replace the knob.
f. Turn the knob clockwise until you reach its stop.
g. Tighten the set screws. Do not use excessive torque when closing the flow
control valves. A stop indicates the closed position.
h. If the needle valve still leaks, refer to the manufacturer's service manual or the
manufacturer's technical representative.
REPLACE FLOW METER TUBE, SCALE, AND FLOAT
If you have isolated the cause of a malfunction to the flow meter tube, you must
replace it. The parts of the flow meter are not interchangeable. The flow meter tubes
are imprinted with numbers which correspond to numbered positions that are on the flow
meter top manifold. To replace a flow meter tube, do the following.
a. Match the number imprinted on the flow meter tube replacement with the
broken flow tube.
b. Replace the flow meter tube, float, and scale. Replacing a float, scale, or flow
meter tube alone destroys the accuracy of the flow meter.
REPLACE A WARPED CHECK VALVE DISC
If you have isolated a malfunction to a warped check valve disc during PMCS,
you must replace it. A warped check valve disc could cause an inhalation or exhalation
check valve to malfunction. Extra check valve discs are supplied with the apparatus.
They are in the small vial stored in the lower case accessory compartment. Refer to
figure 4-1. To replace a warped check valve disc, do the following.
a. Remove the knurled retainer ring, window, gasket, and the valve cage which
holds the disc.
b. Remove the warped disc.
c. Replace the warped disc with the new disc, ensuring that the conical tip points
d. Reassemble the check valve.