Air Conditioner Water Leaks? The Thermostatic Expansion Valve Is To Blame

Air conditioner water leaks increase the risks of mold growth in a home. There is also the fact that when this water drips on furniture, the water can destroy the furniture. This makes finding and fixing the source of these leaks important. Here is what you should know about why a defective thermostatic expansion valve may be to blame for your air conditioner's water leaks.

A malfunctioning thermostatic expansion valve and coil icing

An air conditioning system's thermostatic expansion valve controls the rate at which the liquid refrigerant enters the evaporator coil. The expansion valve not only ensures that the pressure within the coil is low enough to maximize the cooling effect of the evaporating refrigerant, but also protects the system's compressor from the damaging effects of liquid slugging.

However, this gate-keeping role of the thermostatic expansion valve can have a negative effect on the air conditioner's performance if the valve is clogged with dirt, gets frozen or is simply defective. In such cases, the thermostatic expansion valve may end up starving the evaporator coils of the liquid refrigerant. This is a problem since a lower-than-normal rate of flow of the liquid refrigerant will cause an abnormal drop in the evaporator coil pressure. As a result, when the liquid refrigerant changes states, the cooling effect it has on the passing air will be so extreme that it will not only cause the moisture particles in the passing air to condense, but also force them to freeze. This is what then causes evaporator coil icing.

Coil icing and air conditioner water leaks

The formation of ice layers on the evaporator coils usually allows for water hoarding. This is because instead of any formed water flowing into the condensate collector tray and out of the system via the condensate drain lines, it is stored in the evaporator coil area in form of ice. This then creates a situation where any significant temperature changes can cause melting that then causes all the stored water to rush into the collector tray. And when this happens, the sudden onrush of water will overwhelm the condensate tray, something that will then cause air conditioner water leaks. This may then expose your home to the risks of mold growth and property damage.

Preventing this type of air conditioner water leak usually involves replacing the defecting thermostatic expansion valve. It is also possible to reduce the frequency with which the leaks occur by installing a larger condensate collector tray.