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Repair case study: diagnose and quote a non-cooling fridge

The capstone project for Refrigeration Repair Basics — a free Trades course. Pass it and you earn a certificate anyone can verify.

Start the course free Download the project workbook

The project unlocks once you complete the lessons. The workbook is free to download now so you can see exactly what is expected.

What you will submit

A shareable repair case-study document covering the reported fault, an ordered step-by-step diagnosis, the actual fault and fix with safety steps, the parts and tools used, and a clear naira quote with a prevention note.

What to do, step by step

  1. Choose a real non-cooling fridge or freezer you can examine (yours, a neighbour's, a shop's) or use a clearly described sample case. Record the make/type, the gas if known, and exactly what the customer reports it is doing (e.g. not cooling, compressor not starting, cools then warms up).
  2. Write your step-by-step diagnosis in the logical order from this course: the free checks (power, socket, breaker/stabiliser, thermostat knob, seal, wall gap), the compressor running-or-not test, and then the targeted checks (relay/overload, thermostat continuity, temperature feel for gas/defrost, compressor windings). State what you found at each step.
  3. Identify the actual fault and explain the fix clearly — what you replaced or repaired and why — referencing the big four (relay, thermostat, gas leak, compressor) where relevant, and noting any safety steps taken (unplugging, eye protection, handling R600a, brazing precautions).
  4. List the parts and tools used, and write a clear naira quote that separates labour, parts (with markup), gas/consumables, and any call-out fee, giving a realistic total the customer would pay.
  5. Add a short note to the customer with one or two prevention tips (e.g. use a voltage stabiliser, do not pack the fridge against the wall, never defrost with a knife) and an offer of follow-up servicing.
  6. Present everything as a tidy, shareable document or link (Google Doc, PDF, Canva, or a clear typed note) that reads like a real job report you could hand to a paying customer.

Files to work with

Project workbook (fill in, then submit)The whole brief, an evidence checklist, the grading rubric as a self-check and the link-sharing steps in one file. Opens in Word, Google Docs or WPS.Word · 6 KB

How it is graded

CriterionWeight
Diagnosis follows a logical, correct order (free checks, compressor running test, targeted component tests)30%
Fault identification and fix are technically sound and clearly explained25%
Naira quote is clear, fair and separates labour, parts, gas and call-out20%
Safety is correctly addressed (electrical, refrigerant, R600a/flame, eye protection)15%
Document is professional, clear and ready to share with a real customer10%

You need 65% overall to pass. A failed submission comes back with feedback and can be revised and resubmitted.

Before you submit: make your link public

If your work lives in Google Drive or Google Docs, open Share → General access and change “Restricted” to “Anyone with the link” (Viewer). Then paste the link into a private browser window: if it opens without sign-in, you are ready. A private link cannot be graded — it is the single most common reason a good project fails.

Frequently asked questions

Do I have to finish Refrigeration Repair Basics before submitting the project?

Yes. The submission screen opens once every lesson in Refrigeration Repair Basics is marked complete. The lessons are where the methods, the Nigerian context and the worked examples the project depends on are taught.

How is the project graded?

An examiner scores each rubric criterion from 0 to 100 and weights them as shown on this page; you need 65% overall to pass. Most submissions are graded within minutes and you get written feedback on what was strong and what to improve.

Can I resubmit if I fail?

Yes. A failed project comes back with feedback; revise the weak parts and resubmit. A passed project is final — the certificate is issued and cannot be re-rolled.

What do I actually submit?

A write-up of what you did (under 5,000 characters) plus a public link to your work — a Google Drive folder, Google Doc, spreadsheet, GitHub repository or video. The link must open without sign-in; a private link cannot be graded. The free project workbook on this page walks you through all 6 steps.

Is the certificate real?

Yes. Passing this project issues a certificate with a unique verification code. Anyone — an employer, a client, a school — can open the verification page and see that the certificate is genuine and which project earned it.

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Ready to earn this certificate?

Refrigeration Repair Basics is free and self-paced. Finish the lessons, complete this project, and the certificate is yours to share.

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