Air Conditioner Causes Water DamageAir Conditioner Causes Water Damage Question - Hello, We need to ask you about water damage and how an air conditioner can cause this kind of damage. The whole ceiling in one of the rental properties just fell into the living room. All the drywall and insulation from the attic fell and caused damage to our tenants furniture. Thank God the tenants were not at home and injured when the ceiling fell in. The insurance adjuster came out and looked at it and said the problem was because the filter was clogged and air conditioner froze up inside the air handler.

Air Conditioner Causes Water Damage - Answer

When the air conditioner turned off the ice melted and overflowed the pan. It continued to slowly overflow the pan for a few hours until the ice completely melted. The water logged the drywall in the ceiling until it eventually fell in and caused the damage. The insurance adjuster seemed to be very knowledgeable about things like this and I was wondering if a dirty filter could cause such a problem and make the air conditioner ice up? We look forward to your answer. Thanks, Val

Val, the insurance man is correct and I have seen this sort of problem myself. Although most of the time it seems I have to explain what happened after the fact. A lot of people want to blame something or someone except to take responsibility for something they neglected especially something like changing a filter. I have worked for landlords and many landlords who have central air conditioning and heating systems in their houses or apartments have a big problem with getting their tenants to change the filters on a regular basis.

One landlord that called me a lot finally started sending out notices every month to remind his tenants to change their filters because some of the calls I was sent out for were directly related to a dirty filter. The notice explained that the next time they make a trouble call that is directly related to a dirty filter they would pay for the service call.

Because of Neglect? Lack of Maintenance

Air Conditioner Causes Water Damage - In some cases I found no filters in the system what-so-ever and that resulted in the evaporator coil getting clogged with dirt and debris. Some of those evaporator coils had to be removed for cleaning and that is not a cheap process.

It is or should be in every lease contract that a tenant is responsible for changing the filters and if they neglect changing the filter then they are responsible for any service calls that result from the dirty filter. In some cases, it can be an expensive lesson but it is a lesson they will never forget. Guaranteed after they have to pay a $300.00 plus service call to fix the air conditioner because they didn’t change the filter they will never forget to change that filter or filters ever again.

Responsibilities for the Occupants

I’ve rented before and understood that it is my responsibility at a minimum to take care of things like changing the filter. If it was my house the tenants would pay the deductible for the repair to the ceiling and any other damage caused by the dirty, clogged filter. If they have renters insurance then I would defer everything to the renters insurance or at least talk to your insurance agent about that. Hopefully, the adjuster, or perhaps you, took a photo of the clogged filter to show it as a reason for the damage.

Technically speaking the clogged filter blocked the air flow from flowing across the evaporator coil. The evaporator coil needs warm air to flow across it to absorb heat. With no air flow the evaporator temperature drops. Since the blower motor fan is running it still wants to pull air into the air handler and all the warm moist air in the attic infiltrates the air handler and ends up freezing on the cold evaporator coil. The end result is water damage as you seen after all that ice melts and overflows the condensate pans.

The Condensation Drain & Air Conditioner Causes Water Damage

The drain to the condensate pan could be blocked or plugged up but in cases like this depending on the temperature the ice usually melts so fast it overwhelms the drain so it overflows the pan. Responding to calls like this I usually blow the line to make sure it is not clogged but in many cases find the condensation drain line is not clogged, that in fact, the ice melted so fast it overwhelmed the drain line. A tell-tale of this is if the drain pan is empty or full of water. If the drain pan is empty then the condensate line is okay with no plugs but if the pan is full then the condensate line is plugged and needs to be blown out.

Mechanical Code As Related To Air Conditioner Causes Water Damage

air conditioning water damage

Notice the Switches and Sensors near the Drain - These are to detect water leaks and stop the system if a leak is detected

It is common for air handlers to be installed in attics. I have even seen water heaters installed in attics above ceilings. Anytime you have this there is a potential for water damage. In the case of an air conditioner the evaporator coils operate below the dew point and that means the evaporator coil is going to sweat. It sweats because it is removing moisture or humidity from the air. This water needs to have a drain and a place to go.

Usually, the drain is piped to a flower garden where the water will cause no damage. By mechanical code the drain is supposed to have overflow sensors and switches installed in the line so if the line gets plugged up then it kills the air handler and everything stops until a technician can be called to clear the line. Older systems or systems improperly installed do not have these features and that is a disaster waiting to happen.

Condensing Furnaces

If you have a condensing furnace located in the attic you could also have this problem because a condensing furnace condenses some of the moisture in the natural gas and this moisture needs to drain somewhere. It is common for an HVAC contractor to use the same drain that the air conditioner condensation drain uses in the summer to drain all the moisture away from the evaporator coil. Since both systems are likely to use the same drain the mechanical code applies to both for sensors and switches to stop the unit before any serious water damage occurs.

After saying that the next question is: is your unit older than the requirement from the mechanical code? Or did the contractor obtain a permit and if not did they install these required sensors and switches in the drain? Are they functioning properly? It would not hurt to check on these things. Remember, a condensing furnace can cause serious water damage also so the problem would not be limited to only when the air conditioner was running in the summer.

Air Conditioner Causes Water Damage - Conclusion

Lastly, one other thing that can cause an air conditioner to freeze, the refrigerant charge. If you put a clean filter in the system and the system returns to normal and doesn’t freeze up then it is unlikely you have a problem with the refrigerant charge. If it does freeze up because of a low refrigerant charge then you have a refrigerant leak and you need to call an HVAC contractor to repair the refrigerant leak. It would not hurt to call your local HVAC contractor to send out an HVAC tech to check it out and make sure all is well with the heating and cooling system.

I hope that helps. Richard

High Performance HVAC

Air Conditioner Causes Water Damage

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