Course: HET 130 Heating Residential Appliances

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Lab Assignment

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Week 6 Lab Assignment: Common Controls of Force Air Furnaces

Recommended Materials

1. PPE
2. Hand Tools
3. Notepad
4. Pencil
5. Flashlight
6. Fuel source to light a pilot
7. Thermocouple voltage adapter
8. Digital Amp meter

Scope

The student will light a standing pilot, adjust a pilot flame, check a thermocouple, and measure currents through the heat circuit from the thermostat anticipator.

Procedures

1. Locate a furnace with a standing pilot.
2. Remove the burner section door panels.
3. Turn the gas on the furnace.
4. Turn the electrical power source OFF.
5. Locate the gas valve.
6. Turn the knob on the gas valve to the pilot and press the knob down.
7. After holding the knob downward, use an igniter and light the pilot burner assembly.
8. Hold the knob down for about 30 seconds and release. The pilot flame should continue to burn.
9. If the burner continues to burn, locate the pilot flame adjustment screw and turn clockwise two full turns and witness the changes in the flame.
10. Turn the pilot adjustment screw four turns counter-clockwise and witness the changes in the flame.
11. Turn the pilot adjustment screw two turns clockwise to put back into original position.
12. Turn the gas valve off and add a thermocouple adapter to record the DC voltage.
13. Re-light the pilot burner assembly; check and record the milli-volts from the thermocouple.
14. Turn the electric power on.
15. Turn the thermostat to heat and then set the temperature to above the room temperature.
16. Use the clamp-on amp meter and put it around one of the leads on the gas valve.
17. Record the voltage.
18. Check the setting on the thermostat anticipator and adjust to the amperage draw from your reading.
19. Turn off the electric and gas, and then replace the door panels.

Research Questions

1. What were the changes in the flame in the pilot after making adjustments in the pilot adjustment screw?
2. How long did it take to keep the pilot flame burning?
3. Why did you have to depress the pilot knob to allow gas to flow?
4. What is the purpose of the thermocouple?
5. What was the voltage from the thermocouple when it was burning?
6. What is a heating anticipator?
7. What was the reading from the heating circuit?

Click on the file below to download the Lab Assignment
- HET 130 Wk 6 Lab.docx (16.16 KB)