(a) Use hemostats or similar tool to clamp the syringe tubing below the
(b) Retest the water flow from a handpiece or another water outlet.
(c) If you do not see air bubbles, unscrew the syringe handle and
replace the connector tube O-rings.
(d) If air bubbles still appear in the water system, refer to (2) below.
Determine if there is a hole in the water regulator diaphragm. Refer to
Figure 5-2. Pilot-operated regulators.
(a) Disconnect the pilot air tube from the regulator.
(b) Use a valve test syringe to pressurize the pilot air inlet on the
regulator. You should be able to inject only a limited amount of air into the regulator.
The plunger should spring back out by itself when released.
If no defect is noted, check for air in the water supply to the unit.
(d) If you can push the plunger all the way in and it stays there when
you release it, the diaphragm is defective. Install a new one and re-test the unit.
b. Air Bubbles Causing Sputtering. Determine if there is a leaking diaphragm
in the water relay valve. Refer to figure 5-3.