WEEK #5 TOPICS
Quiz ⁄ Review
Diagnosing compressor problems.
After this weekend's class I looked at the chest freezer that team # 1 worked on.
The following is what we know about the freezer:
- The normal running amps for the freezer is 1.7. When it runs it draws 6.7 amps.
- The compressor gets VERY hot when it runs and barely vibrates.
- The suction line does not get cold
- S+ R = 17; C+R= 8; C+S = 9
- .9 ohms was measured between each compressor terminal and ground
What is wrong with the freezer? What led you to your conclusion (discuss each of the clues mentioned above)? What needs to be done to repair this freezer?
A split refrigeration system uses 4 pounds of R-22 refrigerant. Is it a Type I or Type II device?
EPA Refrigerant Certification Exam study guide: 608 Type II (A-1)
List the steps, in their proper order, for a gas fired furnace that uses an HSI ignition.
Using the PT chart in the EPA study guide, illustrate using different refrigerants the EPA's definition of low, high, and very high refrigerants. The EPA's definitions are found on pages 16 and 19.
For the team that removed and reinstalled the inducer motor: When I put the furnace back on the truck a part that belongs between the inducer motor and the heat exchanger fell off. This is the same as a customer finding an uninstalled part after their furnace was serviced. How did this happen? What can be the result of this part not being installed properly? Is this a safety issue? Why or why not?
For the team that was assigned the task of wiring a system: What is the result of not connecting RH to RC? What are RH and RC? To which component in the condensing unit are L1 and L2 from the disconnect box connected to? Prove your answer.
Group Discussions
Using the PT chart in the EPA study guide and an evaporating temperature of 30 degrees, explain the difference between low, high and very high refrigerants.
Lectures
Multi meters (textbook pgs 61, 306-311), small screwdriver, light, nut drivers
Analog manifold gauges (pg 138-139, EPA study guide pg. 9)
Pressure Temperature charts (textbook pg.116 & additional resources #15)
EPA Refrigerant Certification Exam study guide: 608 Type II (pgs 16-18)
Convert the following Celsius temperatures to Fahrenheit: -50, 0, 27, & -30. The conversion formula is on page 7 of the textbook.
Refrigerant tubing and piping (textbook pgs. 70-71, 73, 76)
The contents of an HVAC⁄R technician's bag
Video
Simulated HVAC Service Calls (see the content tree on the left)
Remove and reinstall inducer blower
Wire thermostat, control board, transformer, contactor, and capacitor.
Lab
Cutting, bending, swaging & brazing refrigerant tubing - 1
Combustion analysis demonstration
Checking⁄cleaning burners, and heat exchanger
A⁄C condensing unit schematic & schematic symbols (See Additional Resources)
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