My heat pump is iced over in Pitt Meadows, is that normal?

Some ice on a heat pump's outdoor coil is completely normal in Pitt Meadows winters, where damp air near 0°C is exactly the condition that causes frost to build up quickly. The unit should run a defrost cycle every 30 to 90 minutes and clear itself within 10 to 15 minutes; a light frost or thin layer of ice during that window is nothing to worry about.

When Ice Becomes a Problem

The concern is ice that does not clear, or that builds up into a thick shell covering the coil, the fan or the base of the unit. That kind of icing points to something that needs attention:

A blocked defrost sensor or faulty defrost board is the most common culprit. The unit triggers defrost based on time, temperature or coil sensors, and if any of those fail the cycle never runs. A refrigerant undercharge is another frequent cause: low refrigerant pressure keeps the coil colder than it should be, so frost accumulates faster than the defrost cycle can handle. Poor airflow makes it worse, whether from a dirty air filter inside, blocked return grilles, or debris piled against the outdoor unit. Finally, check that the unit is sitting on a raised pad with clear drainage underneath. Pitt Meadows gets sustained wet weather, and a unit sitting in pooled water will ice over at the base even when the rest of the system is fine.

A few things you can check yourself: make sure the outdoor unit has clear space around it and is not buried in leaves or snow, and confirm the indoor filter is clean. If the unit is running but the indoor air feels cool rather than warm, and the outdoor coil looks like a solid block of ice, switch the system to fan-only or off and let it thaw before calling a technician. Do not chip or pour hot water on the coil.

Do not attempt to add refrigerant yourself. In BC, only a person approved under the provincial Ozone Depleting Substances and Other Halocarbons Regulation may handle refrigerant; it is not a DIY task and the charge has to be measured precisely to the manufacturer's specification.

If the unit is icing over repeatedly despite clear airflow and a clean filter, a technician's diagnostic visit in Pitt Meadows typically runs $120 to $250, with common repairs falling in the $250 to $900 range depending on the cause. Permits for any electrical work on the system in Pitt Meadows come from Technical Safety BC, as do any gas permits if a gas backup appliance is involved.

Persistent icing that the defrost cycle cannot clear is the line between normal operation and a service call; if yours is not clearing on its own, have it diagnosed now, and a Pitt Meadows-area technician is one request away through Vancouver HVAC Pro.