Antihistamines, H1. Histamine antagonists or antihistamines are drugs that relieve allergy symptoms.Histamine is a chemical used to identify and remove substances that trigger an allergic response. Ã¢ There are four histamine receptors &#40;designated H<sub>1</sub>, H<sub>2</sub>, H<sub>3</sub>, H<sub>4</sub>&#41;.
Quick Answer. Blocked condensation drain lines often cause excessive amounts of water in an air conditioner drain pan. These lines are designed to funnel excess water from condensation away from the air conditioning system inside the home. If these lines become blocked, the excess water drains into a drain pan.
In addition to cooling your homeâs air, your air conditioner also dehumidifies it. When air is dehumidified, moisture is pulled out of it. This moisture is known as condensation, and it builds up on and drips off of your evaporator coils. Normally, this is not a problem.The condensation drips into the drip pan and is drained out. If something is wrong with your air conditioner, however, that condensation can freeze up and build a layer of ice on your evaporator coils.rozen evaporator coils can be caused by a number of different problems. Some of the most common include: â 1  Airflow issues. 2  There are many ways that your air conditioner can develop airflow issues (a clogged air filter, duct leaks and blocked air registers, to name a few).