e. Repair or Replace.
(1) Replace damaged nuts, bolts, screws, and washers.
(2) Replace cracked or damaged hub.
(3) Replace cracked or damaged sheave.
(4) Replace damaged shaft key.
(5) Repaint in accordance with Standard Operating Procedures.
(6) Send all replaced parts to Direct Support Maintenance.
f. Installation. (Figure 2-92)
(1) Insert shaft key (5) into shaft keyway (6).
(2) Align and press hub (1) onto R.O. pump shaft (6).
(3) Tighten setscrew on hub (1).
(4) Place sheave (4) onto hub (1) and attach with three lockwashers (3) and three bolts (2).
(5) Use a straight edge to check that outer edge of motor sheave is aligned approximately even with the
pump sheave (refer to figure 2-53).
(6) Replace drive belts in accordance with paragraph 2-76. Tighten drive belts.
Recheck the alignment of both sheaves with a straight edge.
(7) Replace the shroud in accordance with paragraph 2-75.
2-78. AUTOMATIC PRESSURE RELIEF VALVE.
a. General. The automatic pressure relief valve is a safety valve located on the piping between the pulse
dampener and the R.O. vessels. It discharges water when the R.O. pressure reaches 1100 psi (77 kg/cm2). This
paragraph describes the removal, cleaning, inspection, repair, and installation of the automatic pressure relief
b. Removal. (Figure 2-93)
ROWPU piping and equipment can contain extremely high
pressure during and after operation. If this pressure is not
relieved before working on these pipes or equipment, serious
injury or death may be caused. Be sure to open all drains and
vents before beginning any disassembly.
(1) Unscrew the discharge pipe coupling nut (1) from the adapter (5).
(2) Remove plug (2) from the relief valve (3).
(3) Remove adapter (5) from elbow (6).
(4) Remove relief valve (3) from reducing adapter (4).
(5) Remove reducing adapter (4) from pipe tee (7).
(6) Remove elbow (6) from automatic pressure relief valve (3).