The following are some guidelines that should be helpful in determining your maintenance schedule for machine clean out. Refer specific questions regarding the solvents not answered here to your solvent supplier.

CONTAMINATION

Contaminants, such as oils, metal chips, detergents, flux, etc., are usually carried into the cleaner on the work. A build-up of contaminants in the boil sump causes an increase in the solvent boil temperature. As the solvent temperature approaches 7°F over the boiling point of solvent, begin to consider clean out. The procedure includes distillation of the solvent, shut down of the unit, draining/cleaning the boil sump, and adding fresh distilled solvent.

Most contaminants are transferred and collected in the still (if included). The still returns clean distillate solvent back to the degreaser. Therefore, the degreaser will require clean out less frequently. The degreaser can continue operation while the still is shut down and cleaned out.

SOLVENT IMBALANCE

Imbalance can appear as a gain or loss of alcohol. A gain in alcohol occurs in the boil sump. Solvent vapors have 2-3% less alcohol than the liquid. The remaining alcohol stays in the boil sump.; As this builds up, it will affect the temperature in the same way as contaminants. Density of the solvent also indicates the alcohol content. Refer specific questions regarding testing to the solvent supplier.

You will see loss of alcohol at the water separator and/or dryer tank. The function of the water separator/dryer lowers the alcohol content. Water and alcohol will mix. Water removed from the solvent and expelled from the system will take a small amount of alcohol with it. The degreaser will automatically remix the high and low solutions to a certain extent. The weaker solution in the dryer/water separator returns to the unit rinse/clean sump. It passes through the unit and returns to mix with higher concentrated solvent in the vapor/boil sump.

Monitor the density of the solvent in the water separator/dryer reservoirs to determine solvent balance. If the alcohol is low, the cleaning operation may be affected. Experience will determine the proper interval.

EXCESSIVE WATER

When quantities of water are introduced into the system faster than the water separator/dryer can remove it. Excess water can cause the solvent to decompose (i.e. go acid). This can result in damage to the equipment and parts being cleaned.

The first sign of excessive water in the solvent is water vapor (fog or cloud) in the solvent vapor. Solvent vapor is normally colorless. When water vapor is present, it causes the vapor to have a dense, white, foggy appearance. This water vapor will deposit on the part, leaving watermarks and some contamination.

As soon as experience with the system allows, develop a schedule to replace the desiccant dryer media in the dryer tank and/or bleed off water from the water separator tank before fogging ever appears.

A more serious result of high amounts of water is the possibility of solvent decomposition. This can occur when the water mixes with contamination in the solvent. This decomposed solvent can damage the equipment and surrounding metals. Periodically test the solvent condition. Should solvent begin to decompose, immediately shut off heat to the unit and follow the procedures for solvent decomposition.