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.
What to do if your air conditioner freezes. 1  Shut off the A/C to prevent wasting money and risking damage to the compressor. 2  While you wait for the ice to melt, find the condensate drain and make sure it isnât blocked.  Consider opening up the ductwork so you can suction out the water with a wet-dry shop vac.