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.
Thread: water in air conditioner overflow pan. water in air conditioner overflow pan What could cause water to be in the pan that sits under the condenser unit? I still see some dripping from the condenser line that comes out of the house side-wall, so there shouldn't be water in the overflow pan, right? Thanks. 07-22-2007, 01:50 PM #2.