Table 3-1. Troubleshooting.
TEST OR INSPECTION
R.O. PUMP Continued
3. ERRATIC KNOCK OR INCONSISTENT PRESSURE.
Check for pump sucking air through relief valve.
Tighten or replace relief valve.
Check for broken valve spring, worn disc, or worn valve seat.
Replace damaged parts.
4. EXCESSIVE PACKING FAILURE.
Check to be sure packing is installed properly.
Step 2. Check for nicks and burrs on plunger.
a. Buff off minor burrs and nicks.
b. Replace plunger if damaged.
HIGH PRESSURE SWITCH
1. SWITCH WILL NOT ACTUATE (CUT OFF) AT 1250 psig (88 kg/cm2g
Apply pressure to switch and check actuation point with accurate gage.
Check for proper setting of adjustment screw. Setting should be 1250 psig (88 kg/cm2g).
a. Connect test light to N.O. (normally open) and common terminals. Lamp should not light at
b. Raise pressure and check the point at which lamp lights. This is the set point. There is a
mark on the switch cover that shows where the set point is.
c. Drop pressure to zero. Raise or lower setting by turning adjusting screw. Make
adjustments of less than one-quarter of a turn of the screw.
d. Repeat steps (b) and (c) until desired set point is reached.
e. Raise pressure 1250 psig (88 kg/cm2g) and observe test light. The lamp should go on at
1250 psig (88 kg/cm2g)