(2) If there is little or no pressure indicated on the gauge, troubleshoot the
pilot-operated regulators and pre-regulators, below.
TROUBLESHOOT THE PILOT-OPERATED REGULATORS
If the dental operating unit will not come on due to a lack of pressure either at the
regulator outlet, or from leakage around the gasket or diaphragm, use the following
procedures to troubleshoot the malfunction. Refer to figure 5-2.
a. No Pressure at the Regulator Outlet. There are at least three possible
causes of no pressure at the regulator outlet.
Supply is shut off ahead of the regulator.
(a) Turn the master ON-OFF valve OFF and bleed the system.
(b) Turn the manual shut-off valve OFF.
Open the line on the outlet side ahead of the regulator.
(d) Cover the opening with a towel and briefly open the manual shut-off
(e) If there is a good strong flow, proceed with to (2) below.
If there is little or no flow, check the supply at its source.
No pilot pressure to the regulator.
(a) Disconnect the signal air tube from the regulator.
(b) Turn the master ON-OFF valve ON.
Check for air coming from the tube.
(d) If a flow of air is present, proceed with paragraph (3) below.
(e) If the test is abnormal with no air flow, it means that the problem is
upstream from the regulator. Refer to the troubleshooting instructions for pre-regulators
paragraph 5-7, below.