SAFETY VALVES. The ROWPU has three automatic safety devices: the highpressure relief valve,
the highpressure switch, and the rupture disc assembly.
The HIGH PRESSURE RELIEF VALVE is located just behind the PULSE DAMPENER VALVE. If
R.O. pressure goes above 1100 psi, this valve opens automatically and discharges water through a pipe at the
back of the ROWPU. If this valve activates (indicated by sudden pressure loss), immediately press the PUSH
EMERGENCY STOP switch. Open REGULATE PRODUCT FLOW VALVE after unit is shut down. When the
pressure drops below 1100 psi, the valve will close automatically.
Figure 2-44. High Pressure Relief Valve And Rupture Disc
If the valve does not close automatically, notify unit maintenance and do not try
to restart the ROWPU.
After the HIGH PRESSURE RELIEF VALVE closes, clean the R.O. elements (see para. 228) and start the
ROWPU in the normal manner (para. 2-25).
b. The HIGH PRESSURE SWITCH is mounted to the rear of the front panel adjacent to the PANEL
LIGHT. The HIGH PRESSURE SWITCH activates above 1250 psi. If the HIGH PRESSURE SWITCH activates,
the R.O. pump will automatically shut down and the HIGH PRESSURE LAMP (blue) will come on. When the
pressure drops, use the RESET SWITCH to reset high pressure switch. Notify unit maintenance to troubleshoot
the HIGH PRESSURE RELIEF VALVE.
The RUPTURE DISC ASSEMBLY is located on the pipe between the R.O. PUMP and the PULSE
DAMPENER. The rupture disc is a thin sheet of metal that tears when the pressure goes above 1425 psi. Water is
then discharged through the six holes in the top of the assembly. Because the water is under such high pressure, it
will make a lot of noise, and water will be sprayed on the inside of the ROWPU. If the RUPTURE DISC
ASSEMBLY ever activates, press the PUSH EMERGENCY STOP switch and open the REGULATE PRODUCT
FLOW valve. When the pressure has dropped, replace the RUPTURE DISC (see para. 37) and clean the R.O.