When your walk-in cooler or freezer starts acting up, a basic understanding of what might be wrong helps you communicate effectively with your technician — and sometimes avoid a service call entirely.
Here are the most common walk-in issues and how to diagnose them.
Problem: Unit Not Cooling At All
Check first:
- Is the unit plugged in and getting power? Check the disconnect switch and breaker.
- Is the thermostat set correctly? Someone may have accidentally adjusted it.
- Is the condenser fan running? Look at the outdoor condensing unit.
If power is good but nothing’s running: The compressor contactor or thermostat may have failed. This requires a technician.
If the compressor is humming but not starting: This is a locked rotor condition — turn the unit off immediately and call for service. Running a locked compressor will burn the motor windings.
Problem: Unit Cooling But Not Cold Enough
Check first:
- Are the doors sealing properly? Check gaskets for tears or gaps.
- Is the evaporator coil iced over? Heavy frost blocks airflow.
- Are the evaporator fans running? If not, the motor or wiring may have failed.
- Is the condenser coil clean? Go outside and inspect for dirt buildup.
Most likely causes: Low refrigerant charge, dirty coils, failed fan motor, or a door gasket leak. The first three require a technician.
Problem: Ice Buildup on Evaporator Coils
This means the defrost system has failed. Walk-in coolers use electric heaters or hot gas to melt frost off the evaporator coils on a timed cycle.
Check:
- Defrost timer — is it advancing? (Some are mechanical, some electronic)
- Defrost heaters — a technician can test these with a multimeter
- Defrost termination thermostat — this tells the heaters when to shut off
Temporary fix: You can manually initiate a defrost cycle to melt the ice, but the underlying cause needs professional repair.
Problem: Water on the Floor
Inside the walk-in:
- Clogged drain line (most common) — try clearing with a drain snake
- Failed drain heater (freezers) — ice blocks the drain
- Cracked drain pan
Outside the walk-in:
- Condensation from poor door seal
- Refrigerant line insulation failure
- Ambient humidity issues
Problem: Compressor Running Continuously
A compressor that never cycles off is working too hard. Causes include:
- Dirty condenser coils (clean them first)
- Low refrigerant charge
- Door gasket leak
- Thermostat set too low
- Oversized cooling load for the unit capacity
Important: A continuously running compressor will fail prematurely. Don’t ignore this one.
When to Call a Professional
Call Cold Pros when:
- You’ve checked the basics and the problem persists
- The issue involves refrigerant (you need an EPA-certified technician)
- Electrical components need testing or replacement
- The compressor won’t start or won’t stop
- You see or smell anything unusual
Contact Cold Pros for same-day diagnostic service, or call (720) 902-8090 for emergencies.