Thermal Fluid Filtration from MultiTherm®

Filtration will extend the service life of the fluid and also reduce system maintenance. These benefits increase as system operating temperature increases.


  1. Block valves should be positive shutoff (ball valves or equal) to allow for filter cleaning without shutting system down.
  2. A 10 micron filter is recommended. Filter elements can be either sintered metal strainer or high temperature bag filter (Nomex or equal).
  3. Filter housing, piping and valves should be insulated according to guidelines for Thermal Fluids. 

Side Stream

  1. Side Stream configuration is recommended for systems with centrifugal pumps.
  2. Optimal flowrate through the filter is 10% of full system flow. Minimum recommended flowrate is 3%.

In Line

  1. In line filters should be used only with positive displacement pumps (gear). Never install an inline filter on a system that uses centrifugal pumps.
  2. A second filter in parallel (duplex) can be installed in place of the manual bypass for critical applications such as high temperature electric systems.