Improperly assembled regulator.
(a) Disassemble the regulator and inspect all parts.
(b) Look for a diaphragm installed where the gasket belongs. The two
parts are identical except that the gasket has a 9/16-inch hole in the center.
If no problem is found, assemble and re-test the unit.
(d) If the regulator was improperly assembled, reassemble it with all
parts in their proper positions. Re-test the unit.
b. Leakage from the Gasket or Diaphragm Area. Improper assembly or loose
screws is the possible cause for this type of leakage.
Tighten the screws.
If the leaking still persists, use the following procedures.
(a) Disassemble the regulator.
(b) Inspect the gasket, diaphragm, and sealing surfaces on the block
If all parts are in good condition, assemble and re-test the unit.
(4) If the test is abnormal, replace any parts that are defective, then
assemble and re-test the unit.
TROUBLESHOOT THE PRE-REGULATORS
If the dental operating unit will not come on due to a lack of pressure at the pre-
regulators, there are two additional symptoms you may see; either air leaking from a
vent hole or no pressure from the outlet. Use the following procedures to isolate the
malfunction. Refer to figure 5-8.
a. Air Leaking from a Vent Hole. Two possible causes for this symptom are
leakage past the piston seal or exhaust seat, or that the inlet seal does not fully close.
Leakage past the piston seal or exhaust seat.
(a) Test procedures for early design pre-regulators (pre-1979) are to
remove the adjusting screw, spring, and piston from the pre-regulator and inspect the
exhaust seat, stem, piston O-ring, and bore for defects or foreign matter.