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Why is the Evaporator Coil Icing Up?

Why is the Evaporator Coil Icing Up?

Welcome to the WhisperKOOL blog. Here, we discuss troubleshooting tips and preventative maintenance for our WhisperKOOL units, showcase our products, and seek to educate our customers about wine cellar cooling and storage. Today, we’d like to discuss a maintenance issue which sometimes affects our units: evaporator coil ice.

Evaporator Coil Ice

Occasionally, the evaporator coil of a wine cellar cooling unit may ice up. This can happen for several reasons.

In self-contained cooling units, a lack of ventilation may be to blame. The unit blows cold air into the room. If this air has no place to circulate (if the front of the unit is blocked or obstructed), the cold air will circulate back into the unit, chilling the coil to lower temperatures. This can trigger the formation of ice on the coil and on other surfaces. Clogged filters can also reduce airflow over the coils.

In split systems, overcharging can be an issue. If the unit is charged with too much refrigerant, the coil will become colder than intended. This can lead to the formation of ice on the coil.

Coil ice can be a serious problem. Ice begets more ice. Eventually, the entire evaporator coil may be encased in a solid block of ice. This can damage the cooling unit. The fan(s) will strain to pull air through the ice-clogged coil and may overheat. The unit may run continuously, never shutting off, straining the compressor and other components and eventually leading to unit failure.

Even if the unit has an automatic shutoff, what follows could also be tragic. When the block of ice melts, water will almost certainly leak out of the unit, potentially damaging the interior of the unit, wine labels, racking, and walls.

Preventing Coil Ice

Customers can help ensure that their self-contained units will not develop ice on their evaporator coils. By ensuring that their unit has at least three feet of clearance on all sides (five feet is ideal), customers can prevent supply air from recirculating. This will go a long way towards preventing coil ice. Adequate ventilation is vital to the correct operation of WhisperKOOL and other HVAC units.

Technicians can also help ensure that split systems and self-contained units do not develop coil ice by not overcharging the system. By using WhisperKOOL’s new charging charts, technicians can ensure that they charge WhisperKOOL systems with the correct amount of refrigerant.


To conclude, both poor installation and improper charging procedure can cause coil ice to form. To prevent damage to your unit and wine cellar, make sure your self-contained unit has adequate ventilation. Decorative grilles and other objects can obstruct airflow and cause ice to form on the evaporator coil. For split systems, make sure that the unit is not overcharged. Charging charts are included with the condensing units of each WhisperKOOL split system. These charts explain how to properly charge WhisperKOOL split systems. Adherence to these charts should prevent overcharging issues.

Thank you for reading. Stay tuned for an upcoming post about WhisperKOOL’s cold weather start kit, or CWSK. Also be sure to check out our blog to learn more about wine cellar cooling and care. And visit our newly redesigned website for more innovative cooling products and educational materials.

Thanks for being a WhisperKOOL customer!

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