Photograph of  cooling system condensate leaks onto heat exchanger Air Conditioning or Heat Pump condensate leaks, health hazards, mold risk, repairs

  • CONDENSATE LEAKS - CONTENTS: Air Conditioning condensate leaks, health hazards, mold risk, repairs. Why Condensate Pump Leaks & Drain Clog Can Turn off the Air Conditioner
  • POST a QUESTION or READ FAQs about the hazards associated with air conditioner or heat pump condensate drip tray or overflow tray leaks
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This air conditioning repair article discusses the problems and hazards caused by leaky air conditioner or heat pump condensate drip trays and overflow pans.

We address the inspection of air conditioning condensate systems, including air conditioning condensate leaks, health hazards from air conditioner leaks, the related mold risk, and condensate leak repairs, as well as condensate piping, traps, drains, condensate pumps, and the detection and hazards of air conditioning system condensate leaks in buildings.

Air conditioner or heat pump condensate leak health and safety concerns are reviewed here.

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Air Conditioning System / Heat Pump Condensate Leaks

Photograph of  cooling system condensate leaks onto heat exchanger See our complete list of air conditioning and heat pump condensate handling system inspection, diagnosis, and repair articles beginning

When a cooling coil is installed atop a hot air furnace, air conditioning condensate leaks may drip onto the furnace heat exchanger.

Safety Warning about flue gas leaks: leaks onto a furnace heat exchanger can cause rust damage and holes, risking dangerous carbon monoxide leaks and requiring replacement of the heating system.

Further investigation of the source of leakage and the condition of the furnace heat exchanger is needed promptly - this is a safety concern.


Condensate Line maintenance tip: If the condensate line becomes plugged system condensate overflow will spill onto and rust and possibly seriously damage the furnace heat exchanger. During system operation you should periodically confirm that condensate is being discharged properly.

Photograph of  improper condensate drain Photograph of  improper condensate drain Photograph of  improper condensate drain leaks onto attic floor

This sequence of photos shows of an attic air conditioning condensate line what happens when an amateur rigs up a condensate drain in an attic without proper glue, support, and slope.

The plastic piping was not securely supported and when touched, fell apart to spill condensate into the attic floor and into the ceilings below.

Condensate leaks into an attic ceiling risk not only damage to the building but a hidden mold reservoir in the building insulation or on the attic side of the ceiling drywall below.

Since this air conditioning attic system was the same one which showed the dog bowl and kitchen pot in use to catch condensate drips at the air handler unit, the inspector was not remiss in checking the remainder of the condensate drain line rather aggressively.

Photograph of  condensate leaks to interior of blower compartment

Condensate leaks from the air handler's internal drip tray (below the evaporator coil) occur if the internal drain is clogged.

When condensate wets the insulation on the interior of the blower compartment there is risk of problematic mold growth in the system.

In warm humid climates such as the Southern U.S., high levels of condensate production in the air handler unit can also result in movement of condensate downstream into the supply duct, forced there by the blower itself.

Missing air conditioning condensate trap:

[Example air conditioning inspection report language]: We did not see a trap on the condensate line itself - usually installed as good practice - ask your HVAC service person about this detail. It could be required for sanitary or other reasons. CONDENSATE TRAPS have several function including avoiding possible draw of unsanitary air or bacteria back into the building air supply.

Readers who need to clean or unclog a blocked or leaky overflowing A/C or heat pump condensate drain should see CONDENSATE DRAIN CLEAN & DE-CLOG.

Condensate Pump Leaks & Drain Clog Can Turn off the Air Conditioner

In Florida we have air conditioner drain pumps that pump out the water from condensation.

In tracking down an air conditioner condensate leak, I found that the the condensate pump drain line, a small-diameter PVC pipe, was clogged with water mold.

That was why my air conditioner wasn't kicking on.

It would of ended up costing at least a hundred dollars just for a service tech to fix something as simple as that. I had to take the pump apart and clean it. I took off the PVC drain line coming out of inside air conditioner and blow and clean it all out too. - Jacob Behrends, FL

We suspect that due to the clogged condensate drain line on Mr. Behrends' cooling system, A/C condensate was overflowing into a condensate overflow pan that used a sensor switch that responds to water in the overflow pan by turning off the A/C system.

This design is intended to prevent condensate from overflowing the pan and flooding the building - a possible source of mold or other damage - DF


Continue reading at CONDENSATE PUMPS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


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HVAC Condensate Articles

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