Refrigerant Sight Glass?
Pay Attention To The Movement!

Refrigerant sight glass movement?

Well, not exactly the glass itself, but the refrigerant in the glass.

How fast is it moving?

Is it rushing quickly by?

Or is it moving slowly?

Over the years, I have learned to notice the speed of the refrigerant. It actually means something.

If you think about it for a second, you'll realize where I'm going.

Let's say you have refrigeration equipment low on refrigerant.

After repairing the leak, you begin to recharge the system.

With the system low, the refrigerant is rushing through the glass.

But as more and more refrigerant enters the system, the speed begins to slow.

It begins to look like thick syrup, slowly moving through the liquid line, until the glass becomes clear.

What's going on?

Here's an explanation.

As the amount of refrigerant increases in the refrigeration system, the evaporator slowly begins to fill.

As the evaporator fills, the sensing element of the expansion valve cools and begins to close the valve.

As the valve closes, it restricts the flow and causes the refrigerant to back up in the liquid line.

This "backing up" causes the refrigerant to slow, appear thicker, and then clear the glass completely.

So there you have it.

Pay attention to the speed in the sight glass!

With experience, you'll be able to gauge the amount of refrigerant in the system with a quick glance.

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