Where Lennox Heat Pump Water Comes From
Most Lennox heat pumps in Greater Vancouver are ducted systems: an outdoor heat pump paired with an indoor air handler or coil sitting above a furnace, in a closet, attic, or basement. As the system runs in cooling mode, the indoor coil condenses moisture from your home's air, and that water collects in a drain pan and exits through a PVC drain line. In winter, the outdoor unit sheds frost during defrost cycles.
Water around or under the outdoor unit is normal. Water showing up indoors — pooling near the air handler, dripping from the furnace cabinet, or staining a ceiling below an attic unit — is the kind of leak that needs attention.
Because Lennox setups are usually ducted, the leak source can be a few feet away from where you first notice the water, especially when a hidden drain pan overflows and runs along framing before it drips through. Pinpointing it is where a technician earns their keep.
Clogged Condensate Drain and P-Trap
The leading cause of a Lennox indoor leak is a blocked condensate drain. The drain line from the coil pan typically includes a P-trap, and both the trap and the line accumulate algae and sludge over time. When they plug, condensate has nowhere to go: it fills the primary pan and overflows.
Many Lennox installations include a secondary drain pan beneath the coil with a float switch. That switch is a safety feature — when water rises in the backup pan, it shuts the system down to prevent a ceiling-staining overflow. So if your Lennox suddenly stops cooling and you find water near the indoor unit, a clogged primary drain that tripped the float switch is a prime suspect.
The fix is to clear the drain line and trap and confirm the line slopes continuously to its exit. A line that was installed level or has sagged will pool water no matter how clean it is.
Frozen Coil, Dirty Filter, and Pan Problems
A frozen evaporator coil is the other major cause. When a Lennox system is low on refrigerant or starved for airflow, the coil ices over, then floods the pan with meltwater when it thaws. Low refrigerant typically shows up as weak cooling and a system that runs without cycling off — a sealed-system problem for a licensed tech, as refrigerant work is regulated in BC.
A dirty air filter is the most common trigger for that freeze, and the easiest to fix. A clogged filter chokes airflow across the coil; replacing or cleaning it on schedule prevents most freeze-ups. In a typical Lennox furnace-coil setup, the filter sits at the return or in the blower compartment.
Pan and fitting issues round out the list: a cracked or rusted drain pan, a pan that's shifted out of level, or a drain fitting that loosened from settling can all let water bypass the drain and escape into the cabinet or onto the floor.
What to Check Yourself, and When to Call
You can safely do a few things first. Turn the system off at the thermostat to stop making condensate and to keep a tripped float switch from cycling. Check the air filter and replace or clean it if it's dirty. If you can see the drain line's exit outside, make sure it isn't blocked by debris, ice, or a kink.
Stop short of opening the air handler, dismantling the coil, or touching the refrigerant circuit. Clearing a deep drain clog, handling refrigerant, and working inside the electrical cabinet all require proper training and tools. Improper attempts can damage the system or create a safety hazard.
Heat pumps are serviced by our parent company, CanroHeat. If your Lennox is leaking indoors and a filter swap didn't resolve it, call 604-359-1081. We'll trace the leak, clear or repair the drainage, and check the coil and refrigerant if needed.
Repair Cost Ranges in Greater Vancouver
Costs depend on the cause, so here are general ranges only. Clearing a clogged drain line and P-trap and resetting a tripped float switch is usually the most affordable visit. Replacing a cracked drain pan, re-sloping the drain, or installing a new float switch sits in the mid range with parts added.
Refrigerant-related repairs — locating a leak in the system and recharging it — are the most variable and can't be quoted responsibly without inspecting the equipment. Ducted Lennox systems can also take more time to access than a simple wall unit, which affects labour.
For an exact quote on your Lennox, call CanroHeat at 604-359-1081. We diagnose the cause first, explain it clearly, and give you a firm price before any work begins.