Course: HET 130 Heating Residential Appliances

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Lab Assignment

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Week 10 Lab Assignment: Oil Heating Controls

Recommended Materials

1. PPE
2. Hand Tools
3. Notepad
4. Pencil
5. Oil Furnace
6. VOM
7. ruler
8. High temperature thermometer

Scope

The student will develop an understanding of oil heating control systems through testing the ignition transformer, adjusting and testing the electrodes, checking  the cad-cell in the control circuit, and checking the fan/limit switch.

Procedures

1. Locate an oil furnace.
2. Make sure the power source is off.
3. Turn off the oil supply.
4. On the oil burner, open up the ignition transformer.
5. Take a larger screw driver and touch the spring terminals together while removing one end away slowly.
6. You should see a spark coming from the one end of the screw driver to the spring terminal.
7. Turn off the unit.
8. Remove an oil burner from the stock to bench test the burner.
9. Disassemble the burner to remove the oil tube assembly.
10. With a ruler, measure the distance between electrodes and the distance pass the nozzle and the end of the electrodes.
11. Record these readings.
12. Reassemble the oil burner.
13. Turn the unit off and turn the oil back on.
14. Use the high temperature thermostat and install it in the supply plenum.
15. Locate the fan/limit switch.
16. Remove the cover from the fan/limit control.
17. Start the unit up by turning the power source on and setting the thermostat above the room temperature.
18. Witness the movement of the fan/limit control.
19. Record the temperatures where the fan cycles on.
20. Reset the thermostat to below the room temperature and record the temperature where the fan cycles off.
21. Turn the power source off and remove the cad-cell.
22. Take a resistance reading of the cad-cell.
23. Reinstall the cad-cell and put black electrical tape over the window to block out any light.
24. Reassemble the oil burner.
25. Turn the power source on and set the thermostat above the room temperature.
26. Using a watch’s second hand or stop watch, time the amount of time it takes to trip the primary control.
27. Restore the unit back to normal operations.

Research Questions

1. How long of a spark was made with the spark test?
2. What was the spark used for in an oil burner?
3. What difficulties did you run into when adjusting the burner electrodes?
4. What was the ohm reading from the cad-cell?
5. After installing the cad-cell and blocking the window, how long did it take for the burner to cycle off to safety?
6. Was this time normal?
7. What was the temperature of the blower motor cycling on and off from the fan/limit control?

Click on the file below to download the Lab Assignment
- HET 130 Wk 10 Lab.docx (16.34 KB)