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;.
Water leaks in central air conditioners are almost always caused by a problem with the condensate pan or drain pipes. The most common of those problems is a clogged drain line. When your condensate drain line gets clogged, water backs up and builds up in your pan. With nowhere to go, that water will begin to leak over your drain pan and onto your system and your floor. Another problem that can lead to a water leak is a crack somewhere in the pan or in the drain pipes.
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).