If your reach-in runs but is not holding temperature, protect the product and record what changed. Door seals, airflow, controls, and the refrigeration circuit can produce similar symptoms. A dirty coil is one possible cause, not a diagnosis from temperature alone.
Dirty or Blocked Condenser Coils
The condenser dissipates heat from the refrigerant. When it’s coated in kitchen grease and debris, the unit can’t shed heat fast enough, so cabinet temperature climbs. Look at the bottom grille or rear panel (depending on your unit), shine a flashlight at the coil fins, and see if they’re visibly caked. Visible dirt is a reason to inspect the coil, not proof that there is no other fault.
Cleaning commercial coils requires safe access and the correct method. Use the exact model’s schedule and the buildup found at inspection to plan the next visit.
Also check that nothing is blocking the condenser fan. A plastic bag, a cardboard box, or a pile of debris against the intake will cause the same symptom.
Door Gaskets and Seals
Open the door, close it on a dollar bill, and pull. If the bill slides out easily, the gasket isn’t sealing. A leaking gasket lets warm, humid air into the cabinet continuously. The compressor runs more than it should, the evaporator frosts over, and eventually the box can’t keep up.
A weak seal needs assessment: door alignment, dirt, and the gasket profile can all affect the result. A technician confirms the cause before selecting a replacement.
While you’re at it, check that the door is actually closing fully. A hinge that’s sagging or a door that got knocked slightly out of alignment is common, especially on units near a busy prep line.
Evaporator Coil Iced Over
If the evaporator (the coil inside the cabinet, usually behind a panel in the back wall) is coated in a solid block of ice, airflow through the box is restricted and temperature rises. This typically happens when the defrost system fails, or when a door gasket has been leaking long enough to overwhelm the defrost cycle.
You can manually defrost by turning the unit off and opening the door, but that’s a temporary fix. If it ices up again within a day or two, there’s an underlying issue. Diagnosing defrost heaters, thermostats, and timers requires a meter and disassembly. That’s a tech job.
Low Refrigerant
Refrigerant doesn’t “wear out,” but it can leak. Signs of a refrigerant issue: the compressor runs constantly, the evaporator coil is partially frosted rather than fully frosted (or not frosted at all where it should be), and the cabinet slowly drifts warmer over days or weeks rather than failing suddenly. You can’t check refrigerant charge yourself; it requires gauges and an EPA Section 608 certification to handle. If you suspect a leak, call a tech.
Compressor or Electrical Issue
If the compressor isn’t running at all, you’ll usually hear the difference: no hum, no vibration. Check the obvious things first: power to the unit, the circuit breaker, and the reset button if there is one. Beyond that, a failed start relay, capacitor, or compressor itself is not a DIY repair. Compressors on commercial reach-ins are expensive, and misdiagnosis gets costly fast.
How a Tech Actually Diagnoses This
When I send a tech to a warm reach-in, here’s the sequence they follow:
They check the condenser first, visually and with an airflow test. Then they pull temperatures at the supply and return air to see what the actual delta is. They’ll put gauges on the system to read suction and discharge pressures, which tells them whether refrigerant charge is in the right range and gives clues about compressor health. They’ll check defrost cycle operation and test door heaters if the unit has them. On the evaporator side, they’re looking at coil condition, airflow, and fan motor amps.
The measurements determine the repair scope and timing. More than one fault can be present.
What You Can Check Before You Call
These are safe to check on your own:
- Condenser coils: look for blockage or heavy grease buildup
- Door gaskets: dollar-bill test on all corners
- Door alignment and closure
- Condenser fan: confirm it’s spinning when the compressor is on
- Power and circuit breaker
If those check out and the unit is still not cooling, product is at risk. For restaurants, a reach-in that can’t hold 41°F is a food safety issue, not just an equipment problem.
Call Us
If the simple checks don’t resolve it, or you already know the condenser is caked and want it handled properly, call us. We cover the Bay Area and can typically get someone out same or next day. We’ll give you a straight answer on whether it’s worth repairing or whether the unit is at end of life. Book at adriumservice.com.
Related guides and field notes
Separate cabinet temperature from the display
Keep these observations with the service request: the independent temperature reading, the controller setting, the room temperature during the busy period, and whether the door closes by itself. A display can disagree with a separate probe; the technician checks calibration before changing controls.
Listen for changes in the evaporator fan without pressing a door switch or opening guards. Some fans pause with an open door or during defrost. Note ice or water visible through normal access, but do not chip ice or clear an internal drain.
The technician compares airflow and actual temperatures with the controls, then tests the condenser fan, defrost system, and refrigeration circuit as needed. Pressure, superheat, subcooling, and compressor current need to be read together against the model procedure. A single reading does not choose a replacement part.
Model instructions: True service and installation manuals. Use the manual for your exact cabinet; access and maintenance intervals differ.
The service visit is $99, credited toward the repair. After diagnosis, we give you one written total repair price to approve before work starts.