Why Ice Leads to Leaks
Ice and water leaks are often the same story told in two parts. When a coil gets cold enough, moisture freezes onto it. When that ice melts — during a defrost cycle outdoors, or when the unit cycles off — it turns back into water. If the ice was thin and normal, the meltwater drains away as it should. If the ice was heavy and abnormal, the sudden melt overwhelms the drain pan and you get a leak.
So a heat pump that ices up and then leaks usually has too much ice forming somewhere. The key question is where: light frost on the outdoor unit in a Greater Vancouver winter is expected, but ice on the indoor coil, or a thick layer encasing the outdoor unit, is a fault.
Understanding which coil is icing, and why, tells you whether you're looking at normal winter behaviour or a problem that needs fixing before it floods or damages the system.
When Ice Is Normal (and When It Isn't)
In winter heating mode, the outdoor coil naturally collects frost because it's pulling heat from cold, damp Vancouver air. To handle this, every modern heat pump runs an automatic defrost cycle: it briefly reverses to warm the outdoor coil, melts the frost, and that meltwater drips from the base of the outdoor unit. A light coat of frost that clears every so often is the system working correctly.
It becomes a problem when the outdoor unit is encased in thick ice that doesn't clear, when ice covers the fan blades, or when the unit is frozen solid for hours. That suggests the defrost cycle isn't working — a failed defrost sensor, control board, or reversing valve — or that drainage beneath the unit is freezing and building up.
Ice on the indoor coil is never normal. In cooling mode, an iced indoor coil points to low refrigerant or restricted airflow, and it's the classic setup for an indoor leak when it thaws.
Common Causes of Abnormal Icing
Dirty filters or a dirty coil are the most common and most preventable cause. Restricted airflow lets the coil run colder than designed, so it ices up. Cleaning or replacing filters on schedule, and keeping the outdoor unit clear of leaves and debris, prevents a lot of icing.
Low refrigerant drops coil temperature and promotes freezing, usually alongside weak heating or cooling. This is a sealed-system issue that requires a licensed technician, since refrigerant handling is regulated in BC.
A failed defrost system — sensor, timer, or control board — stops the outdoor unit from clearing frost, so it builds into a block of ice over a cold snap.
Blocked drainage under the outdoor unit matters in winter: if defrost meltwater can't drain and refreezes, it slowly entombs the base. Low airflow from a failing blower or fan has the same chilling effect as a dirty filter. And a unit sitting in a spot where roof runoff or downspouts dump onto it can ice up from the outside in.
What to Do, and What to Leave to a Tech
There are a few safe steps. If the indoor unit is leaking and you see ice on the indoor coil, turn the system off and let the ice melt fully before doing anything else; running it while frozen can damage the compressor. Check and clean the air filter — a dirty filter is the leading cause of icing. Clear leaves, snow, and debris away from the outdoor unit so it can breathe and drain.
Never chip or hammer ice off the coils or fins; you'll bend the delicate fins or puncture tubing. Don't open the refrigerant circuit or the electrical cabinet, and don't pour hot water on electrical components. Defrost controls and refrigerant work require proper diagnosis and tools.
Heat pumps are serviced by our parent company, CanroHeat. If your unit ices up repeatedly, freezes solid, or leaks when it thaws, call 604-359-1081. We'll find out why it's icing and fix the root cause — not just melt it and move on.
Repair Costs in Greater Vancouver
Costs hinge on the cause, so here are general ranges. A cleaning-related fix — clearing the coil, replacing a filter, and clearing drainage so the unit defrosts properly — is usually the most affordable. Replacing a defrost sensor or control board sits in the mid range with parts. Refrigerant-related icing, where the system is low and needs leak diagnosis and recharging, is the most variable and can't be quoted without inspecting the equipment.
Leaving abnormal icing unaddressed risks bigger costs: a compressor run while frozen, or water damage from repeated thaw-and-overflow cycles, are far more expensive than the original fault.
For an accurate quote, call CanroHeat at 604-359-1081. We diagnose why your heat pump is icing, explain it clearly, and price the repair before any work starts.