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Low refrigerant charge and the search for real data

June 22, 2021

I had read about how low refrigerant charges could increase compressor operating temperatures and decrease the amount of oil flowing to compressors, but I had never been able to find results from any tests. After discussing this with MACS, we decided to do some testing to get some real data.
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Refrigerant capacity and mobile A/C service: part 2

June 15, 2021

One of the most frequently asked questions on tech help-line calls concerns refrigerant capacity: How much refrigerant is in that mobile A/C system, and have you checked to be sure the refrigerant is pure?
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Focus on the condenser!

May 31, 2021

In last week's article, we focused on applying temperature testing to an evaporator in an orifice tube system. In it we illustrated how and why a low liquid level in the evaporator can cause a large temperature differential between the inlet and outlet. We also indicated how and why raising the liquid level will cause the temperature differential to decrease. Now it is time to focus on the condenser.
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Temperature testing detective work: The search for a diagnosis

May 25, 2021

Last week we closed our blog post with a discussion about an orifice tube system which had an evaporator outlet temperature that was about 20° warmer than the inlet. We mentioned that this could be an indication of a restricted orifice tube or a refrigerant undercharge. In applying this to diagnostics, it is important not only to understand what this represents, but also why.
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What is your temperature testing data telling you?

May 18, 2021

If air conditioning systems were transparent where we could see inside them, then diagnostics would be faster and easier. We could look at the systems and see things right away that affect system operation, like restrictions and liquid levels in evaporators and condensers.
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Temperature Matters

May 11, 2021

In addition to having good contact with connectors and getting accurate readings, there are some other important things to remember when doing temperature testing.
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Pass the temperature probe

May 4, 2021

The first step is to run the A/C system for a few minutes to let it stabilize. Then both probes should be connected side by side at both points that will be temperature tested in the system. For example, if you were testing the temperature drop across the condenser, this would need to be done on both the discharge line and the liquid line.
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Are you using the right tools for mobile A/C repair?

April 30, 2021

Your shop’s R-134a recovery/recycling/recharge (R/R/R) machine is in well-maintained condition. You have an R-1234yf gauge manifold set and an R-1234yf machine is on order; should arrive shortly.
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The pressure is on

April 19, 2021

By appearance, radiator caps seem to be a simple device. Yet, many technicians do not understand the cap’s real function
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Temperature testing accuracy

April 13, 2021

Temperature readings can be easily used to determine if an orifice tube system might be undercharged, and they can also be used to charge an orifice tube system. But if the readings are not accurate, all they are going to do is cause you problems.
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ParkSmart Bunk A/C System Freightliner P3 Cascadia

March 24, 2021

The ParkSmart auxiliary HVAC system has been offered to replace the standard auxiliary HVAC unit.
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Why does the replacement compressor use different oil (than the original unit)

March 23, 2021

That is viscosity and specifically why a replacement compressor might use a different viscosity oil than its OEM counterpart.
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