Capped Condensate Drain Vent
The vent on the drain line has a cap on it.
Less commonPlan for itHeating equipment
Why it matters
Open vents prevent the creation of a siphon effect in the condensate line, which could inadvertently draw condensate back into the furnace.
How common is it?
Didn't come up in the homes HomeCloud evaluated Sep 2025 to Oct 2026, but it's on our list of HVAC findings.
Counted by the finding's name on HomeCloud reports, so the true number can be a little higher.
How soon to fix it
HomeCloud reports list this as something to plan for rather than an emergency.
More HVAC resources
What kind of HVAC system do I have?How to tell a heat pump from a gas furnace with AC, a packaged unit or a mini-split, and how to read the equipment label for its size and age.The best HVAC brandsWho makes the major brands, how to compare equipment fairly, and why the installer matters as much as the brand.HVAC maintenanceWhat you can do yourself (filters, the outdoor unit, the condensate line) and what a yearly tune-up covers.
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