UNIT 90 REVIEW QUESTIONS ANSWER KEY GO BACK TO INDEX
90-1) List the four phases of a planned maintenance service call.
90-2) What is the purpose of checking the supply voltage both before and after
operating the system?
90-3) Name key safety aspects of combustion appliances that should be checked on a
planned maintenance service call.
90-4) List operational checks to make during an air conditioning planned maintenance
service call.
90-5) Why should caution be exercised when replacing a low efficiency air filter with
a higher efficiency air filter?
90-6) How can performing planned maintenance save the customer money?
90-7) How does planned maintenance improve system reliability?
90-8) How can the technician determine what the system voltage parameters are?
90-9) How can the heating operation of a heat pump be checked without gauges?
90-10) The supply voltage to a system drops below the minimum voltage when the
unit is operated. What could be causing this?
90-11) What color should the flames be in a correctly adjusted gas burner?
90-12) List the items to be checked when servicing a belt drive system.
90-13) How can a worn belt be identified?
90-14) How is a temperature-pressure relief valve on a hot-water boilertested?
90-15) Describe how sound is used in predictive maintenance.
90-16) Discuss the difference between predictive maintenance and planned
maintenance.
90-17) What side of an air conditioning “A” coil generally needs cleaning?
90-18) How does the technician know which way to install an air filter?
90-19) List some maintenance items that can be inspected visually.
90-20) How are water pumps in hydronic heating systems checked?
UNIT 91 REVIEW QUESTIONS ANSWER KEY GO BACK TO INDEX
91-1) What are the most common types of refrigeration system contaminants
introduced because of improper installation?
91-2) How does carbon affect a system?
91-3) What effect does the presence of non-condensables have on a system?
91-4) What system condition is indicated by copper plating?
91-5) What are the most common sources of refrigeration system contamination?
91-6) Explain how contaminants from a previous compressor failure can cause a
replacement compressor to fail.
91-7) What is the purpose of collecting system baseline performance data?
91-8) List the system characteristics that are checked when taking system baseline
performance.