Outdoor Unit Completely Dead: Compressor Confirmed Failed

An outdoor unit is completely dead and the compressor is the verdict. What has to be ruled out before that verdict can be trusted.

By Team Snowflake | Updated 24 Aug 2026

Teaching case based on recurring Snowflake service patterns; identifying details are combined.

How this presents

A system producing no cooling at all, with the outdoor unit running and the indoor units delivering air at room temperature. Nothing has been changed or worked on recently. The pipework carries no frost and no temperature difference is present.

Setup: Daikin Wall-mountedOver 15 yearsHDBChoa Chu Kang
Misread as: An expensive verdict reached too quickly, when something smaller might be the real cause.
Check first: Which cheaper causes were tested first, and what the readings showed

What else produces this

A compressor conclusion is credible only when the cheaper explanations have been eliminated one at a time and can be named. The refrigerant charge, the electrical parts that start and run it, the flow controls and the heat-rejection side all produce partial or total loss of cooling. Every one of them costs a fraction of a compressor. Working through them in order turns an expensive quote into a supported one, and it is what any household is entitled to ask about.

A correct refrigerant charge removes the commonest cause before any component is condemned.
Starting and running components testing within specification rules out the cheap electrical failures.
A clean outdoor coil with normal airflow eliminates the heat-rejection side.
No pressure difference developing between the two sides of the system, with the compressor drawing current, confirms it is turning without compressing.

Why it happens

A compressor raises the pressure of the refrigerant, and every other part of the cycle depends on that happening. Internal wear, valve failure or a seized mechanism stops it, and once it does the system circulates nothing useful however healthy the rest of it may be. The distinguishing evidence is a machine drawing power and producing no pressure difference at all, which is a state no other fault reproduces.

What resolution involves

The verdict is confirmed and the replacement priced against the age and condition of the rest of the system. The transferable part is the process rather than the outcome. Ask which cheaper causes were tested and what the results were, because a compressor diagnosis without those answers is a guess wearing an expensive number.

How to tell it worked

Pressure difference across the compressor while it draws current. That single measurement distinguishes a compressor that has failed from a system starved by something upstream of it.

Before you approve a quote

An expensive verdict needs its exclusions named

Charge, electricals, flow controls and the outdoor coil all cost far less and produce similar symptoms.
Ask which of them were tested and what the readings were. A verdict without exclusions is a guess.
A compressor drawing current and producing no pressure difference is the evidence that settles it.

Questions this case answers

Is it worth swapping the compressor on an older aircon?

Not before the cheaper causes are cleared. The refrigerant charge, the electrical components that start and run it, the flow controls and the heat-rejection side each produce loss of cooling, and each costs a fraction of a compressor replacement.

How is compressor failure actually confirmed?

Pressure on both sides of the system while the compressor draws current. A working compressor creates a clear difference between them. One that turns without compressing produces almost none, and that is the finding that settles it.

Can a sealed compressor be repaired on site?

No. The motor and pump sit inside a welded casing that is not opened in the field, so the choice is a swap or a replacement unit. When one has genuinely failed nothing works, which looks unambiguous from the outside, but several cheaper faults produce the same loss of cooling and only measurement tells them apart.

What should a diagnosis leave me with?

The measurements and what was ruled out, alongside age, the condition of the rest of the system, and what a matched replacement costs against a new one. On an older system the compressor rarely stands alone as a decision, and both prices are worth having.

Describe your situation

Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.

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