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.
Common reasons why an air conditioner freezes up: Inadequate Air Flow. Anything that restricts the air flow over the coil surfaces can disrupt the balance of your system and cause icing. Dirty filters, damaged blower motors and dirt build-up on the evaporator coil can all seriously obstruct air flow.