Your unit runs and runs, but the box keeps creeping warm
That’s the call we get most. The walk-in compressor is cycling on and never seems to shut off, the air coming off the evaporator feels weak, and the thermometer that used to sit at 36°F is now showing 44°F by mid-afternoon. The instinct is “it’s low on refrigerant.” Sometimes it is. Often it isn’t. Here’s how to tell the difference before you spend money.
A refrigerant leak and a dozen cheaper problems all produce the same symptom: a unit that works hard and can’t hold temperature. The trick is ruling out the common stuff first.
Causes, most likely to least likely
Dirty condenser coils. This is the number one cause of “it won’t get cold” in a Bay Area kitchen, hands down. The condenser coil dumps heat, and when it’s packed with grease, dust, and flour, the system can’t shed heat and the box drifts warm. During a summer heat stretch in the Tri-Valley, ambient temps in a back kitchen or a rooftop unit can climb past 100°F, and a dirty coil that limped along in spring suddenly can’t keep up. Clean coils fix this for the cost of a service call.
Bad door gaskets or a propped door. A torn gasket or a door that doesn’t seal pulls warm, humid kitchen air into the box nonstop. The unit runs forever fighting a leak it can’t win. Easy to overlook, cheap to fix.
Iced-up evaporator or a failed defrost. If the inside coil is a block of ice, airflow stops and the box warms even though the system is full and running. A stuck defrost timer or heater is the usual cause.
Low refrigerant from an actual leak. Now we’re at the real thing. Refrigerant isn’t a consumable. It runs in a sealed loop and doesn’t get “used up.” If a system is low, it’s because refrigerant escaped through a leak: a corroded coil, a vibration-fatigued joint, a bad Schrader valve, or a cracked weld. Signs that point here specifically:
- Hissing or bubbling near the lines or coil
- An oily, dirty film around a fitting or on the coil (refrigerant oil leaks out with the gas)
- Ice forming on the copper line near the compressor when the rest of the system is warm
- The system was just “recharged” a few months ago and is low again
That last one matters. If someone added refrigerant and you’re low again, you don’t have a refrigerant problem, you have a leak that was never fixed.
Compressor or component failure. Less common, more expensive. A worn compressor can run constantly without pulling the box down even with a full charge.
What you can safely check yourself
You don’t need a tech to rule out the easy stuff:
- Look at the condenser coil. If it’s furry with grease and dust, that’s likely your whole problem. Shut the unit down and have it cleaned.
- Check the door gaskets. Run your hand around the seal for cold-air leaks, look for tears, and make sure the door actually latches.
- Confirm the thermostat setting. It happens more than you’d think. Someone bumped it.
- Check the drain and look for ice. A solid ice block on the inside coil points to defrost, not refrigerant.
- Make sure airflow isn’t blocked. Boxes stacked against the evaporator or the condenser shoved against a wall both choke the system.
What you should not do: open the sealed system, touch refrigerant lines, or buy a can of anything to “add.” Handling refrigerant requires EPA 608 certification by law, and doing it wrong wrecks the system or vents regulated gas. Our techs are EPA 608 certified and trained on R-290 (A3) hydrocarbon systems, which is the right call when flammable refrigerant is involved.
What needs a tech
Leak detection is the job. A certified tech uses an electronic detector or nitrogen pressure test to find where the refrigerant is escaping, repairs the leak, evacuates the system, and recharges it to the exact spec on the nameplate. There’s no shortcut and no honest version that skips the leak search. EPA rules require finding and fixing the leak before recharging a commercial unit.
For Bay Area kitchens, one local note: our hard water mostly punishes ice machines, not walk-ins, through scale buildup. That’s a filter and descaling issue, not refrigerant. But the same heat that strains a walk-in condenser also runs ice machines hard all summer, so if both are struggling at once, it’s usually airflow and ambient, not a coincidence of two leaks.
What it costs
Rough ballpark for a small commercial system: leak find and repair with recharge typically runs $250 to $600, depending on where the leak is and how much refrigerant the unit takes. Coil-level leaks (corroded evaporator or condenser coil needing replacement) go higher, often $700 to $1,500 or more, because the part and labor are the real cost. Prices vary by system and situation, so call for an actual quote.
One thing worth knowing: low refrigerant makes a compressor run hot and starve for oil. A leak you sit on long enough can turn a $400 repair into a compressor replacement. Refrigerant pricing has also climbed as older blends get phased out, so a big recharge isn’t trivial. Fixing the leak early is almost always cheaper.
Call us
If you’ve checked the coil, gaskets, thermostat, and drain and the box still won’t hold temp, call us. Call sooner if you hear hissing, see oily residue near the lines, smell anything off, or the unit was recharged recently and is low again. If product is sitting above 41°F, move it to backup and log your temps first, then call.
We service commercial refrigeration and ice machines across San Ramon, the Tri-Valley, and the East Bay, same or next-day when we can. EPA 608 Certified, #1279674151528. (925) 999-4095.