Identify the standardized electrical symbols for the

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50-15)Identify the standardized electrical symbols for the following common controls: indoor fan relay, humidistat, manual reset, crankcase heater.
If there is a 240 V circuit that will be carrying 30 amps using #10 wire size, what is the maximum length of the two wire run that would limit the voltage drop to 3%?
In question #20 what would be the answer if the wire size is #12, the voltage is 120 V, and the amperage is 15 amps?
50-18)List the 5 major electrical devices in the heating circuit diagram in Figure 50-30.
161 50-19)Explain what a limit switch is, as well as its function and how it affects the control circuit.
50-20)State why the legend and the notes are an important part of an electrical diagram.
UNIT 51 REVIEW QUESTIONS ANSWER KEY51-1)List the safety precautions that should be observed when starting a gas furnace. Don't turn anything on until you have inspected the furnace! Check for the presence of gas in the area around the furnace. Make sure there are no combustible items stored near the furnace. Check the vent. Check for combustion air. Do not position yourself directly in front of the furnace while it is lighting. Once the furnace lights, check the vent to make sure it is working. 51-2)Explain the difference between natural gas and propane.
51-3)What is the most common manifold pressure for natural gas furnaces?
51-4)What is the most common manifold pressure for propane furnaces?

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