Dirty or fouled condenser coils are one of the most frequent service problems in the commercial refrigeration and air conditioning fields today. If a condenser coil is dirty or fouled, its ability to reject heat is severely affected.
Remember, the main function of the condenser is to condense the refrigerant vapor to liquid. Condensing is system dependent and usually takes place in the lower two-thirds of the condenser. Once the saturation or condensing temperature is reached in the condenser and the refrigerant gas has reached 100 percent saturated vapor, condensation can take place if any more heat is removed. As more heat is taken away from the 100 percent saturated vapor, it will force the vapor to become a liquid, or to condense. When condensing, the vapor will gradually phase change to liquid until 100 percent liquid is all that remains. This phase change, or change of state, is an example of a latent heat rejection process, as the heat removed is latent heat, not sensible heat.