With the exception of high-temperature processes such as brick making, a liquid ring vacuum pump operating at 130° F (55°C) and above may be an indication of a problem, although the operating temperature does not necessarily damage the pump. The vacuum pump usually operates at a temperature 10°-25°F (5°-14°C) higher than the temperature of the seal water flowing to the pump. Most often, high pump temperature is an indication of low seal water flow. Low flow can be caused by plugged orifices or spray nozzles and/or low seal water feed pressure.
Low seal water flow can be the cause of low vacuum levels. Therefore, vacuum pumps operating at unusually higher temperatures can be a sign that requires investigation.
High pump operating temperatures may also occur with proper seal water flows. Sometimes, the process service is just hot. In these instances, the elevated pump temperature is normal.