At weekly intervals, or sooner if operating conditions demand, the refrigeration condensing unit heat exchanger should be thoroughly cleaned with compressed air or a vacuum cleaner to remove all dirt, dust or other material that would reduce the heat transfer effectiveness. If the dirt and dust is not removed, the compressor discharge pressure will become too high and result in overheating of the compressor motor. Safety controls in the form of a high pressure and thermal overload switch are incorporated in the machine to protect it. A sight glass is included in the high pressure refrigeration liquid line. Under normal operating conditions, the sight glass will be clear, without the presence of bubbles. In the event the sight glass contains bubbles, or no liquid refrigerant, the refrigeration system is operating incorrectly due to a dirty condenser, defective expansion valve or low refrigerant level as a result of a leak. Under these conditions, the system should not be operated until the faults are corrected.

SAFETY VAPOR CONTROL

At least once a month, check the operation of the safety vapor thermostat. This can be done by bringing the unit up to boiling temperature (vapor condensing on cooling coils). Open the disconnect switch. Wait until vapors are at the top of the cooling coils and close the disconnect switch. Refrigeration will start immediately. Heating elements should not be turned ON, due to the SVC turning off the heating system.

After vapors drop below the cooling coils (none or very little vapor condensing on cooling coils) turn heat switch OFF. Reset Safety Vapor Control and turn the heat switch to the ON position. Heating elements should energize.

Bad calibration, improper setting or a defective control can cause a malfunction of the Safety Vapor Control.

CLEANING TANK

The system requires very little maintenance other than an occasional draining and cleaning. Turning ON the heat and draining the clean condensate from the reservoir tank as it is produced can clean the boiling sump. As soon as the solvent level is down to the heaters, the heat switch must be turned OFF. The dirt and sludge should be removed through the drain valve or the clean-out door before refilling with clean solvent.

Mild non-scratching abrasives in powder form and soap can be used to clean the stainless steel tank. Steel brushes and sponges should not be used to clean the stainless steel as they may leave particles embedded in the stainless steel surface, which would lead to rusting.

SOLVENT MAINTENANCE

Most solvents can be recycled almost indefinitely with proper care in distillation and water removal. The solvent should be periodically checked for proper pH levels, acid acceptance or the contamination introduced into the solvent and water in system (either by condensation or by parts).

The degreaser removes oil, chips, and most organic soils. Solvent normally flows from the condensing coils to gravity water separator, to spray reservoir, to rinse sump, to boil sump. The solvent flows opposite the path of work travel to provide the purest solvent for rinsing.

The degree of contamination governs the degree of part cleanliness. Briefly, a “CLEAN DEGREASER” produces “CLEAN PARTS”. Oil contamination increases the boiling temperature of a solvent. When the boiling temperature is exceeded by 7-10°F, the machine should be cleaned out. Aluminum or magnesium fines or trimmings can cause accelerated solvent breakdown. With these materials, a stricter maintenance schedule to monitor solvent acidity or acid acceptance levels is recommended.

Discard solvent with high acidity and completely clean and flush equipment with a solution of water and soda ash (2 oz. per gallon). Caution: NEVER USE CAUSTIC SODA. Flush and rinse with water, dry completely and refill with fresh solvent.

Set up a routine schedule for equipment and solvent maintenance as soon as experience with the system allows. Factors that determine the frequency of maintenance include: amount of time the equipment is used, amount of work processed (pounds, pieces, etc.) and the quantity and type of contamination introduced. Observe the parts for acceptable cleanliness. As solvent becomes contaminated, it becomes a less effective cleaner.

When required, perform a thorough clean out. Don't just drain the solvent. Remove the clean out door(s) and clean sludge from the sump bottom and tank walls. Don't forget to clean the heating elements. Even with a distillation system, you need to clean the degreaser periodically. Clean the still more frequently to prevent solvent decomposition.

Periodically test the solvent for its normal characteristics. These tests indicate if the solvent is suitable for continued use in the system. An acidic solvent can form violent reactions that may be hazardous to the equipment and to personnel. Acid acceptance testing will monitor the solvent's ability to neutralize acid residues and correlates directly with useful life of the solvent.

Note that in the early phases of acidic solvent, test results may indicate in the satisfactory range. Discoloration of the cleaner and parts may occur before the solvent tests show the solvent to be unacceptable. We recommend that you perform these tests on a weekly basis, until you establish the normal readings for the application. Update chart whenever production level changes, clean out is performed, etc. Once the normal reading curve is established, you can perform the tests less frequently (either monthly or as determined by your application). Also, perform the tests if you notice a change in the solvent appearance, or part cleanliness. Schedule your clean out routine to occur before test results sharply deviate from the normal curve. If using EnSolv, follow the guidelines in the EnSolv Acid Acceptance Test Kit Procedure.