Can a Dirty Filter Cause Water Leaks in a Furnace?

Air Conditioning

• If you have a heating and cooling system, the air-conditioning evaporator on top of the furnace by the supply duct could be leaking water into the furnace. If the air filter is dirty, the slower moving air through the filter can cause the temperature to get colder than normal and the ductwork to sweat. The sweat runs down the ductwork and into the furnace. If you close too many duct vents in the home while the air conditioning is running, the poor air flow will cause condensation in the duct vents that can run into the furnace.

Humidifier

• Furnaces with humidifiers can have water leakage inside the furnace if the humidifier leaks. Humidifiers can leak because of a loose water line connection, or the supply tube for the water could have a leak. Another cause of water leaking into the furnace could be an incorrectly installed or clogged evaporator pad in the humidifier.

Drain Tubes

• Drain tubes on high-energy furnaces can become disconnected, causing water to leak into the furnace. High-energy furnaces produce a large amount of condensation that drains from the furnace through the drainage tubes. If water is leaking into the furnace, and it isn’t associated with a humidifier or air-conditioning unit, the drain tube may have come loose, causing condensation to leak into the furnace.

Damage From Water Leaks

• Water leaks in the furnace can cause furnace parts to rust. When the rust becomes severe, you risk the chance of the furnace shutting down and becoming unusable. A water leak from the drain tubes can corrode the steel parts of the furnace quickly. The water has an acidic value, which is bad for steel. If water is leaking into the furnace, you need to have the problem corrected right away to protect the furnace from damage.