What solvent maintenance actions should you take in case of machine downtime?

Basic information

It is possible that solvent baths can behave differently after machine downtime, and that irregularities and even process problems can occur when operation resumes. Signs indicating changes in solvent include reduced stabilizer concentrations, increased acid numbers or even blue to green discolored solvent or water phases all the way to initial rust formation in the water separator. These observations are evident across all solvents.

Following machine downtime, solvent maintenance measures should be implemented more frequently to validate the condition of the solvent before normal operation resumes.


When a cleaning machine is switched off – especially after previously high utilization – the solvent in the wash/flood tank, in the water separator or in the vapor generator/distillation unit has different levels of stabilization, or is exposed to different contaminations.

During downtime, since no stabilizing or solvent distillation can take place, acids can continue to form even at lower temperature levels.

Following machine restart the stabilizer content could therefore go down, alternatively, the acidity level could go up. This observation is for instance often made when chlorinated oils are used in large quantities.

Simple guideline

The simple guideline below outlines recommended solvent maintenance actions in case of (unscheduled) machine downtime. It also explicitly includes preventive measures that should be carried out before a scheduled downtime.

We hope this guideline will help you get back to normal operation. If you have any questions, do get in touch!

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