F91 is one of the most searched Panasonic codes in Singapore, and one of the most misunderstood. Here is the straight version from technicians who deal with it weekly.
What F91 means
Panasonic error code F91 means a refrigerant cycle abnormality. The system is not circulating refrigerant the way it should. Most often the gas is low because of a leak, sometimes it is a compressor or sensor fault, and occasionally a blockage in the circuit. It is a high severity code: running the unit in this state risks the compressor. Full code table in our Panasonic error codes guide.
What usually causes F91 in Singapore
The leading cause by far is a refrigerant leak, and in local installs the usual suspects are flare joints that have worked loose over years of thermal cycling, corroded piping, or poor insulation work from a previous installer letting joints sweat and corrode. Less commonly we find a failing compressor that cannot build pressure, a blocked capillary or strainer, or simply a system that was never charged correctly after a past repair.
The mistake to avoid: topping up without testing
The tempting cheap fix is a gas top up. But if F91 came from a leak, new gas exits through the same hole, and you will be paying for top ups every few months while the compressor runs stressed in between. As we say on every job: topping up without fixing the leak is renting cold air. The correct sequence is pressure test first, find and fix the leak, then charge the system properly. Our aircon gas top up page explains how we test.
What you can safely try
Switch off at the breaker for five minutes and restart, once. If F91 returns, switch the unit off and leave it off until it is diagnosed. A compressor running on low gas cools poorly, overheats, and shortens its own life every hour it runs.
What it costs
A pressure test and leak repair is a mid-range job depending on where the leak sits, joints are cheaper than concealed piping. If the compressor itself is the fault on an older unit, we will give you the repair versus replace numbers honestly before you commit. Diagnosis rates are published on our aircon repair in Singapore page.
F91 on your screen right now?
WhatsApp +65 8818 5781 with your model number and a photo of the display. We will tell you honestly whether it is a quick fix, a repair worth doing, or, on an older unit, whether the money is better spent on a replacement. Our aircon repair in Singapore service covers every brand with published rates, same day slots when available, and a 30 day labour warranty.
