The Mepco brand Vacuum Breaker is a simple device which provides a positive means of relieving or "breaking" a vacuum at predetermined setting. It is not intended to control or maintain a specific degree of vacuum, but rather is designed to prevent such damage as; freezing coils resulting from the hold back of condensate due to an induced vacuum, collapse of jackets on steam jackets and kettles caused by vacuum when steam is shut off, water hammer in any heating equipment due to vacuum caused by throttling of control valves. Mepco vacuum breakers are furnished with 3/8" male pipe thread and are set at the factor to begin opening at 2 inches of vacuum. They may be field adjusted from 1" to 28" of vacuum. Maximum operating pressure is 65 lb.