A frozen packaged AC unit at a medical clinic
A recent job in the Los Angeles area, September 2026. Ice ran down the suction line to the compressor. We thawed the unit, added refrigerant and replaced the filter.
In this guide
The call: a clinic’s AC had frozen up
The packaged air conditioner on a medical clinic’s roof had frozen. A packaged unit keeps the whole system in one cabinet, often on the roof, with ducts running down into the building.
What the photos show
The photo at the top of this page is the open compressor compartment, and the first thing you see is ice. On the left is the compressor, a Copeland scroll by Emerson, as its label says. Next to it, the big copper line that carries refrigerant back to the compressor, the suction line, is buried in thick white ice all the way to the bottom of the cabinet.
The second photo is the unit on its pad on the roof, side panels off, with hoses running into the compressor compartment and a refrigerant cylinder beside it. The badge on the cabinet reads Tempstar.
Why an air conditioner freezes
The indoor coil of an air conditioner runs cold, but normally above the freezing point of water. It can drop below freezing when too little air moves across it, because of a clogged filter, a blocked return or a weak blower. It can also drop below freezing when the system is short of refrigerant, which lowers the pressure and the temperature inside the coil.
Once ice starts, it insulates the coil and chokes the airflow further, so it grows. On this unit the ice had reached the suction line, all the way down to the compressor.
What we did
We let the ice melt first. Then we added refrigerant to the system and replaced the air filter. After the service the unit worked well.
About the refrigerant
Refrigerant isn’t fuel. A sealed system doesn’t burn through it, so a unit that needs refrigerant has lost some. Adding it brings the charge back up. If the same unit comes up short again, the next step is a leak search. For a look at what that search involves, see the Lennox package unit we brazed on a roof.
Adding refrigerant is work that requires EPA Section 608 certification, which we hold at the Universal level.
What clinic and office staff can check
Keep the filters on schedule. A clogged filter can starve a coil of air until it ices up, and it’s the cheapest of these problems to prevent. If the staff can’t say when the rooftop filters were last changed, that’s worth finding out.
Keep supply and return grilles clear. Boxes or furniture stacked against a return starve the unit of air.
If the air turns weak or warm, or you see ice on the unit or water where it shouldn’t be, switch the cooling off and call. Running the fan alone can help the ice melt. Don’t let anyone chip at it: the tubing under the ice is thin, and a puncture turns a service call into a leak repair.
Commercial AC service in Los Angeles
We service packaged rooftop units and split systems for clinics and offices across the Westside, Hollywood and the San Fernando Valley. The $85 service call is credited toward the repair if you go ahead, and repairs carry a 30-day labor and 90-day parts warranty. CA BEAR registered (#A 50636), EPA Section 608 Universal certified, $1,000,000 general liability insurance. See our HVAC services or call (213) 205-2055.
FAQ
Why does a packaged AC unit freeze up?
The indoor coil normally runs cold but above freezing. Too little air across it, from a clogged filter or a weak blower, or too little refrigerant in the system lets it drop below freezing. Moisture from the air then freezes on the coil, and the ice can spread back along the suction line toward the compressor.
What should I do if my AC is iced over?
Switch the cooling off. Running the fan only can help it thaw. Don't chip at the ice: the tubing underneath is thin. Check the filter, and call if the unit freezes again after the ice is gone.
Can you just add refrigerant to a frozen AC?
On this unit we thawed it first, then added refrigerant and replaced the filter. Refrigerant isn't used up the way fuel is, though. A system that is short has lost some, so if a unit needs refrigerant again, the next step is finding where it's going.
Who is allowed to add refrigerant?
Federal rules require EPA Section 608 certification to service equipment that holds refrigerant. Epic Star holds Section 608 Universal certification.
Do you service AC units at clinics and offices?
Yes. We service packaged rooftop units and split systems on commercial buildings across the Westside, Hollywood and the San Fernando Valley. The $85 service call is credited toward the repair if you go ahead.
AC, heater or mini-split acting up? We cover LA and the Valley.
Call (213) 205-2055 or text a photo of the unit and its model sticker.