Outdoor unit completely dead: compressor confirmed failed
A silent outdoor unit does not always mean the worst. The cheaper parts fail far more often than the compressor, so we tested those first. On this twelve-year-old Daikin, the order of checks decided whether the bill was small or large.
By Team Snowflake | Updated 28 Jul 2026
Case summary
Daikin Wall-mounted12 years oldHDBChoa Chu Kang, Singapore
- Concern
- The owner hoped a cheap capacitor or relay swap would save the unit and avoid a major bill.
- Found
- Compressor failure confirmed after cheaper causes were ruled out
- Key check
- Manual start drew high power and tripped protection, showing the compressor itself had failed
- Result
- The owner chose a new unit after reviewing both prices. We wrote up the test results as a clear record of what was checked and ruled out.
What we were told
The unit had been blowing air but not cooling for two days. The outdoor side was completely silent, with no fan and no hum when the aircon was switched on. The owner suspected a capacitor fault and hoped that was all it was, since a capacitor is a cheap part to replace.
What we checked
We worked through the outside parts before testing the compressor. The order matters. A dead capacitor or stuck relay gives the same silent unit but costs far less to fix, so those get ruled out first. We tested the run capacitor, then checked the relay contacts. Only after both passed did we try a manual compressor start. The power it drew on that start would tell us whether the compressor could still run.
Run capacitor tested within its expected range, so it was not the cause.
Relay contacts were clean and closing correctly, so the relay was ruled out too.
Wiring to the unit was sound, with no break or loose terminal to explain the silence.
On a manual start, the compressor drew high power and tripped protection within three seconds.
What we found
The compressor had failed inside the sealed casing after years of heat and use. On the manual start it drew too much power and tripped protection within seconds, which is the behaviour of a motor that can no longer turn. The fault was internal, not in the capacitor, relay, or wiring we had already cleared. Those earlier checks were what let us call this with confidence rather than guess.
What fixed it
A sealed compressor cannot be repaired on site. That left two options. A compressor swap keeps the rest of the system, or a new unit replaces everything. On a twelve-year-old unit, a swap is possible but costly, and the other parts carry the same age and wear. We laid out both prices side by side. At this age the swap cost gets close to a new unit, and the new unit carries a fresh warranty on every part.
Outcome
The owner chose a new unit after reviewing both prices. We wrote up the test results as a clear record of what was checked and ruled out.
What this case teaches us
A silent outdoor unit needs the cheap parts checked first
- A dead capacitor or stuck relay makes the same silence as a failed compressor, but costs a fraction to fix.
- Compressor failure is only confirmed by a manual start. Drawing high power and tripping within seconds is the proof.
- On a unit past twelve years, a compressor swap can cost close to a new system. Ask for both prices side by side.
Questions this case answers
How is compressor failure actually confirmed?
Is it worth swapping the compressor on an older aircon?
Can a sealed compressor be repaired on site?
What should a diagnosis leave me with?
Ready to get started?
Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.