Fault-finding
The AC runs but the room does not get cold
Check in this order: filters and indoor coil, then the outdoor condenser, then the running current, then the gas charge. A blocked condenser and a low charge produce the identical complaint, and the condenser is far more common here — which is why measuring comes before refilling.
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Start with airflow, because it is free
Filters clogged with a season of dust, and an indoor coil matted behind them, cut airflow enough that the room never cools while the unit runs continuously. This is the single most common cause we attend and it needs no parts. Pull the filters and look at the coil behind them before assuming anything more expensive.
Then the outdoor unit, which nobody looks at
The condenser rejects the heat, and in this climate it clogs with dust, seed fluff and construction grit. A blocked condenser cannot dump heat, so the system runs hard and cools poorly — indistinguishable from low gas to anyone who has not measured. Check that it is clear, that the fan spins freely, and that nothing is boxed in around it.
Measure before diagnosing gas
Running current against the rating plate, suction pressure, and the temperature difference across the indoor coil. A healthy unit shows a clear split between return and supply air. Those three readings separate dirt from charge from a failing compressor. Skipping them is how a cleaning job becomes a gas bill.
If the charge is low, find the leak
Refrigerant is sealed, not consumed. A unit genuinely low on gas has a leak, usually at a flare joint, a service valve core, or a corroded coil. Refilling without tracing it means paying for gas again next season. We say plainly when a top-up is a stopgap rather than a fix, and we put that in writing.
Why is my AC running but not cooling?
How can I tell dirt from low gas myself?
Without gauges you cannot do it reliably, and that is exactly why the misdiagnosis is so common. What you can check is whether the filters and the outdoor coil are visibly dirty and whether anything is obstructing the outdoor unit. If all three are clean and it still will not cool, the next step genuinely needs a meter and gauges.
The unit is icing up. What does that mean?
Ice on the indoor coil or the pipework means the coil is running colder than it should, which is caused by restricted airflow or a low charge — the same two suspects. Switch the unit off and let it thaw fully before anyone inspects it, because a frozen coil hides the reading that would tell you which.
Should the outdoor unit be in the shade?
It helps, as long as shade does not mean enclosed. The condenser needs free air around it far more than it needs shade, so a unit boxed into a balcony recess or hemmed in by a wall performs worse than one in full sun with clearance. Airflow first, shade second.
Rather have it done?
A service is a deep clean of both coils, the filters and the drain, plus a set of measurements that show whether the unit is actually healthy. Servicing starts at PKR 3,000, and gas refilling starts at PKR 6,000 — but a unit needing gas has a leak, and refilling without finding it is a yearly bill, not a repair.
AC servicing and gas refilling in Islamabad — prices and scope