TM 10-4610-241-10
TO 40W4-13-41
2-2. ROWPU CONTROLS AND INDICATORS- cont.
p.
Safety Devices. Refer to figure 2-17. The ROWPU has four automatic safety devices: the high pressure relief
valve, high pressure switch, low pressure switch and rupture disc assembly.
(a)
(b)
(c)
(d)
High Pressure Relief Valve. The high pressure relief valve is located just behind the VENT VESSEL gate
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
shutdown. When the pressure drops below 1100 psi, the valve will close automatically.
CAUTION
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 (para. 2-12) and restart the ROWPU
(para. 2-9).
High Pressure Switch. 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 will come on. Notify unit
maintenance to troubleshoot the high pressure relief valve. When malfunction is corrected, use the RESET
SWITCH to reset high pressure switch.
Low Pressure Switch. The low pressure switch is mounted on the back of the control panel adjacent to the
PANEL LIGHT. The low pressure switch activates when water pressure to the R.O. pump drops to 10 psi
(Models WPES-10, WPES-20, and WPES-30) or 40 psi (Models H-9518-1, H-9518-2, and H-9518-3). If the
LOW PRESSURE SWITCH activates, the R.O. pump will automatically shut down and the LOW
PRESSURE LAMP will come on.
If required, notify unit maintenance to troubleshoot the malfunction.
When malfunction is corrected, use the RESET SWITCH to reset low pressure switch.
Rupture Disc Assembly (Models WPES-10, WPES-20 and WPES-30 only). 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, notify unit maintenance to replace the rupture disc and clean the R.O. elements (para. 2-12). Notify
unit maintenance to troubleshoot the high pressure relief valve and the high pressure switch.
Change 2 2-23
