UNIT 56 REVIEW QUESTIONS ANSWER KEY GO BACK TO INDEX
56-1) How does the refractory temperature affect the combustion efficiency?
56-2) What are normal on and off temperature ranges for the settings on the fan
control?
56-3) Describe the procedure for purging a single pipe gravity feed system.
56-4) Describe the procedure for purging a two pipe system?
56-5) What pieces of information are necessary to determine combustion efficiency?
56-6) What can cause the heat exchanger flow resistance to increase after several
years of operation?
56-7) Why must a negative pressure be maintained on the heat exchanger?
56-8) How is the door switch wired into the system in Figure 56-25?
56-9) What opens the contact on the safety switch in Figure 56-25?
56-10) Why does soot accumulation on the inside of the heat exchanger reduce system
efficiency?
56-11) How does the cad cell operate to secure the burner in the event of a flame out?
56-12) What smoke spot number represents correct combustion?
56-13) How is net stack temperature calculated?
56-14) Discuss the relationship between the over fire draft and stack draft.
56-15) What is the CO2 percentage for a perfect stoichiometric mix of oil and air?
56-16) Why do we not try and adjust the CO2 percentage to the perfect stoichiometric
percentage?
56-17) Why does excess combustion air reduce combustion efficiency?
56-18) How should the output of an oil furnace ignition transformer be tested?
56-19) What components on an oil furnace should be changed annually?
56-20) What angle nozzle is usually used with a round combustion chamber?