EXERCISES, LESSON 5
INSTRUCTIONS: Answer the following exercises by circling the lettered response that
best answers the question.
After you have answered all of the exercises, turn to "Solutions to Exercises" at
the end of the lesson and check your answers. For each exercise answered incorrectly,
reread the lesson material referenced after the solution.
Which of the following is a potential cause for air bubbles in the water system?
a. Foot control mounting screws are loose.
b. Debris is clogging the holdback filter.
The water relay valve has a leaking diaphragm.
d. There is no air at the air regulator outlet.
You are testing for an audible leakage in the foot control. Which of the following
procedures would you use if you think the signal relay is leaking air?
a. Remove, inspect, and if necessary, replace the holdback filter
b. Tighten the two Phillips-head screws at the center of the foot control
Check the air flow around the tilt valve stem using soapy water.
d. Remove the signal relay and inspect the stem, O-rings, and seats for debris or
The dental operating unit will not come on, and the ON-OFF indicator shows ON.
Which of the following procedures might you use to isolate the malfunction?
a. Troubleshoot the time control valve.
b. Troubleshoot the pre-regulators.
Troubleshoot the foot control.
d. Troubleshoot a syringe or handpiece holder.