Selecting the correct size steam trap for a system is an important factor in its operational efficiency. For example, an oversized trap will operate less efficiently than a correctly sized one, and will tend to create abnormal back pressure. Moreover, the installation cost will be higher and the operational life expectancy will be reduced.
Manufacturers of steam traps provide information in the form of capacity ratings and related data to make these selections easier. Data should be based on hot condensation under actual operating conditions rather than cold-water ratings. If possible, always try to determine the basis for a manufacturer’ s ratings. Table 10-1 and the sizing example were provided by Sarco Company, Inc., a manufacturer of steam traps.