Lesson 171 - Troubleshooting

Now that you’ve learned a lot about coolant maintenance protocols and Zebra products, you can troubleshoot some common problems.

These problems are categorized by protocol, as they cross multiple products. We’ve also presented them as questions frequently posed by customers.

First Protocol — Concentration:

Why doesn’t my refractometer read as a percentage of coolant?

The scale on the

is called Brix, which was designed to measure sugars in solution. However, not all coolants measure one-to-one on the Brix scale. You must check the product data to see if the manufacturer specifies a “refractometer factor.” This factor is multiplied by the scale reading to determine the concentration value in percent.

I calibrated my refractometer with water and the line went through the zero. But when I try to measure coolant, nothing is there. Where’s the line?

Due to evaporation, the concentration of your sump may have increased, and may be higher than the scale on your refractometer. It is best to get a refractometer with a scale wider than the goal concentration. This will allow you to see better what these over-concentration values are.

Why is the Machinist Mixer not outputting 5% even though I have the dial set at 5?

The dial is graduated, which means it has numbers allowing you to know exactly how far you are turning the dial. It is not calibrated, which means the numbers have to be matched to something solid – like a coolant concentration. They can’t be calibrated because your concentrate viscosity will vary depending on the product and its temperature. Use a refractometer to determine what dial position works for your fluid. Once the setting is determined, record it for safekeeping. You can also lock the dial using our


Our Machinist Mixer isn’t delivering the needed concentration of coolant. What’s wrong?

Was the discharge hose modified? Is anything restricting the flow of incoming water? This mixer uses venturi valves to create a vacuum in the chamber which pulls concentrate up the standpipe. Putting a long hose on the discharge end of the mixer means the vacuum pressure goes down, so less concentrate is pulled up for mixing. The maximum length on the discharge hose should not exceed 40″. It may be that you need a

, which can proportion AND pump the fluid at greater distances.