Articles
18Nov

Flooding

Flooding (also known as ‘flood back’) is the term used to describe the condition when liquid refrigerant reaches the compressor. This occurs when the amount of liquid fed to the evaporator is more than can be evaporated. There are a number of possible causes of flooding including: • TXV oversized for the application • TXV misadjusted (superheat too low) • System overcharged with refrigerant • Insufficient airflow through evaporator • Dirty evaporator • Evaporator fans not operating • TXV bulb not...

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07Nov

Evaporator Vs. System Superheat

Q: What is the difference between evaporator superheat and system superheat? Superheat varies within the system depending on where it is being measured. The superheat that the thermal expansion valve is controlling is the evaporator superheat. This is measured at the outlet of the evaporator. The refrigerant gains superheat as it travels through the evaporator, basically starting at 0 as it enters the evaporator and reaching a maximum at the outlet as the refrigerant travels though the evaporator absorbing heat. System superheat...

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25Oct

What is Evacuation

Q: What is the purpose for ‘evacuating’ a refrigeration system? Evacuating a refrigeration system serves two primary objectives: 1. Removes non-condensables 2. Dehydrates (removes water vapor) If non-condensables such as air are not removed, the system will operate at higher than normal condensing pressures. This happens because the air is trapped at the top of the condenser, effectively reducing the condenser capacity. Increasing the condensing pressure results in higher compression ratios and higher discharge temperatures, both of which decrease system...

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