Table 23. Troubleshooting (ROWPU) CONTINUED
TEST OR INSPECTION
10. HIGH-PRESSU RE LAMP WILL NOT GO OFF. continued
Remove cover plate of high-pressure switch.
Using the multimeter, check for 120 Vac from ground and normally open and normally closed
switch terminals. (Refer to schematic, figure 11 2.)
a. If power is on the normally OPEN contact, replace highpressure switch unit.
b. If no power is found on the common contact, check for loose or broken wires and contacts.
Repair or replace damaged wiring.
Step 5. Check high-pressure solenoid.
Solenoid should not be actuated.
a. If solenoid is actuated, check for shorts in wiring or connections. Repair or replace wiring.
b. If solenoid is still actuated, check for shorted solenoid contacts. Replace solenoid.
11. HIGHPRESSU RE RELIEF VALVE OPENS REPEATEDLY.
Highpressure water released from the highpressure relief
valve can cause severe injury. Take proper safety measures to
Start ROWPU system.
Increase pressure (R. O. PRESSURE psi gage) by closing the product water control valve.
Record pressure at which highpressure relief valve opens. Repeat three times.
Relief valve should open above 1100 psig.
Drain and vent system to reduce R.O. vessel pressure to zero psig (zero kg/cm2).
Temporarily install an R.O. PRESSURE psi gage of known accuracy by removing pressure tube
from existing gage and connecting to new gage.
Repeat steps 1 through 3.
If the reading between the two gauges is less than 2%, adjust high pressure valve to open at
1100 psig. If the reading is more than 2% or the valve cannot be adjusted to 1100 psig,
replace the valve.