"The compressor is gone" is the sentence customers fear most, and in our experience it is wrong often enough to be worth checking properly. A compressor that will not start is frequently a victim, not the cause.
The three checks that come first
Run capacitor
The dual-run capacitor gives the compressor and outdoor fan their starting torque. In Jeddah heat these fail fast - the top swells, capacitance drops and the compressor hums then trips on overload. A capacitor is a fraction of the cost of a compressor and takes minutes to replace.
Contactor and supply
Pitted contactor points, a loose terminal or a voltage drop on a shared circuit can leave the compressor without a clean supply. We measure voltage at the compressor terminals under load, not just at the wall.
Thermal overload and control board
A tripped internal overload, a board that is not sending the run signal, or an inverter module fault will all look like a dead compressor. On inverter units we read the fault codes before condemning anything.
When it really is the compressor
We confirm with winding resistance across the three terminals, insulation resistance to earth, and starting current against the nameplate figure. A compressor with a shorted winding, an open winding, or one that is mechanically seized is genuinely finished. Signs customers notice:
- The breaker trips shortly after the outdoor unit starts.
- A metallic knocking or rattling from the outdoor unit.
- The outdoor fan runs but the unit never gets cold and pressures never move.
- Burning smell at the outdoor unit.
Repair or replace?
| Situation | What we usually advise |
|---|---|
| Unit under 6 years, rest of the system healthy | Replace the compressor with a matching one and renew the filter drier. |
| Unit 8–12 years, coil also corroded | Replace the outdoor unit or the whole system - a new compressor in a corroded shell is money lost. |
| Window unit over 10 years | Compare against a new inverter unit; the running-cost saving often pays the difference within two summers. |
| Inverter unit with a failed module | Board replacement first; compressor only if the windings test bad. |
You get the comparison as numbers, not opinions: repair cost, expected remaining life, and the price of a new unit with installation.
Why compressors fail early in Jeddah
Three reasons dominate: running with low refrigerant after an unrepaired leak (the compressor loses cooling and overheats), a choked outdoor coil that raises head pressure, and voltage fluctuations during peak summer load. Fixing the leak and keeping the condenser clean is cheaper than any compressor.
If your unit is short of gas, read AC gas refill in Jeddah - that visit is designed to prevent this exact failure.
What a correct replacement includes
Compressor price is only part of the bill. A replacement done properly also includes:
- A new filter drier - the old one has absorbed moisture and will not protect the new compressor.
- Cutting out and re-brazing the suction and discharge lines with nitrogen purge, not open-flame brazing that leaves scale inside the circuit.
- Pressure testing the re-made joints before charging.
- Deep vacuum to remove air and moisture, held to confirm it seals.
- Charging by weight to the rating plate figure, then verifying superheat.
- Running the unit under load and measuring current against the nameplate.
If a quote is close to the price of the compressor alone, one of those steps is probably being skipped - and that is how a new compressor fails inside a year.
Warranty and follow-up
Ask what is covered: the part, the labour, or both, and for how long. Keep the invoice with the compressor serial number on it. If the unit trips again in the first weeks, that serial and the recorded pressures are what any warranty claim depends on.