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.
), you can figure out why your central air conditioner is icing up. Your air conditioner can freeze up for a variety of reasons, so we will discuss them from the most common to some of the more rare causes of ice up., you can figure out why your central air conditioner is icing up. Your air conditioner can freeze up for a variety of reasons, so we will discuss them from the most common to some of the more rare causes of ice up.