Flooding of water in your furnace ducts can cause considerable damage and health issues. It is important to empty the ducts of water as soon as possible to avoid ongoing issues. Turn off your furnace as soon as you realize that there is a possibility of water entering the ducts to avoid damage to it. The furnace can be damaged if it tries to blow air through water-filled ducts.
Removing Water From Furnace Ducts
During heavy rain or flooding, water can get into the ducts causing damage to the ducts and the furnace. The water and any accompanying mud must be removed immediately to avoid problems. If the problem is not too serious, you can remove the water with cloths and a wet shop vac, making sure you do all areas that you can get to.
If the problem is very serious and there is a lot of water, you may have to pay for the local fire department, or a water removal service to come and pump out the water from the vents, although you may be able to rent a sump pump and do it yourself, pumping the water into the sewage system.
After you have removed all the water that you can, turn on the furnace and blow warm air through the ducts until they are completely dry. You will need to remove any ductwork insulation that has been wet from floodwater, as it is impossible to disinfect and will harbor mold spores.
Ongoing Moisture Problems
The main problem associated with water in the furnace vents is that it provides a perfect environment for mold to grow. Using the system blasts mold spores through the house, causing serious health problems and starting new mold growth in any slightly damp areas.
Another common problem is corrosion in valves. Check your furnace valves regularly if they have become wet to ensure they are working properly.
Avoiding Water Damage
There is little you can do to avoid water getting into the ducts in a flood, but if your house sits where water can get in during heavy rain, you should consider diverting water around the home. You will need to dig a trench to divert the water away and permanently stop the water from entering ducts.
Dig the drainage trench about 6 feet away from the outside of your home and about 20 inches deep. It should divert the water to the lowest point on the property, but be aware of any potential problems to neighbors from your water flooding their property that you could be liable for.
The trench should be lined with 1 inch gravel before a perforated drainage pipe is installed in it. Backfill it with more gravel, finishing with sod.
If you are regularly inundated with water, you might have to investigate the viability of rerouting the ducts through the roof space or attic.
Remember that if your basement is filled with water, don’t be in a hurry to pump it all out. Pumping a couple of feet a day is better to avoid the walls collapsing from outside soil pressure.