Why is My Cool Room Icing Up? (And How to Fix It)

Walking into your cool room and seeing a block of ice encasing the evaporator unit is a hospitality nightmare.

It seems contradictory: ice is cold, so surely ice is good?

Actually, ice is an insulator. When cool room ice build-up covers your coils, it stops the cold air from getting out into the room. Your motor runs harder, the temperature in the room rises, and your stock starts to spoil.

In Darwin’s humid climate, moisture is always trying to get into your cold space. If you are noticing ice, here are the likely causes and a checklist to run through before you call us.

Commercial cool room icing up in Darwin due to humid air, showing ice buildup on evaporator coils and interior surfaces
The 3 Most Common Causes

1. The "Open Door" Policy (Human Error)

This is the #1 cause of icing in Darwin. If the door is left open for deliveries, or if the door seal is torn, warm, wet tropical air rushes in. That moisture has to go somewhere. It hits the coldest part of the room (the evaporator coils) and freezes instantly. If this happens faster than the fridge's defrost cycle can melt it, you get a block of ice.

2. A Failed Fan Motor

Your evaporator fans push cold air around the room. If one of those fans burns out, the air stops moving. The cold air sits stagnant around the coils, dropping the temperature so low that ice forms rapidly, eventually turning the whole unit into a snowball.

3. Low Gas (Refrigerant Leak)

This is the one that requires a technician. If your system is low on gas, the pressure drops. This changes the boiling point of the remaining refrigerant, often causing the coil to freeze up in a specific pattern (like a strip of ice across the middle) rather than an even frost.

Check These 3 Things" (Before You Call Us)

Save yourself a call-out fee by checking these three common culprits first.

1. Check the Door Seal and Hinge

  • Is the door closing all the way? Sometimes a box is preventing it from shutting tight.

  • Run your hand around the seal. Is there a draft? If warm air is getting in, that is your problem.

  • The Fix: Clear the doorway. If the seal is broken, book a refrigeration repair in Darwin to get it replaced.

2. Check the Stock Loading

  • Did you just get a massive delivery? If you stack boxes right in front of the fans, you choke the airflow. The air bounces back onto the coil and freezes it.

  • The Fix: Move stock at least 30cm away from the fan unit.

3. Check the Fans

  • Listen to the unit. Can you hear the fans whirring?

  • Look (safely) at the fans. Are they spinning?

  • The Fix: If a fan is silent or stationary while the compressor is running, turn the unit off and call us.

Technician checking evaporator fan and door seal inside an iced commercial cool room to identify icing causes in Darwin
When to Call the Pros

If the door is shut tight, the fans are spinning, and the boxes are clear, but you are still seeing freezer icing up, you likely have a technical fault.

It could be:

  • Low Refrigerant: A leak in the system.

  • Defrost Failure: The heater elements that melt the ice automatically have failed.

  • Thermostat Issue: The system doesn't know when to turn off.

Don't attack the ice with a screwdriver! We have seen too many evaporator coils punctured by frustrated business owners trying to chip the ice away. This turns a $300 repair into a $3,000 replacement.

If you are iced up, turn the system off to let it thaw and call Fridgie Didge immediately.