Refrigerant Recovery

EPA 608 Type 3 Chapter 7 (Take full course for free)

In this module, we will discuss about the different refrigerant recovery methods and a couple of techniques for faster recovery. Skip to quiz!

1. Recovery Procedure

Recall that refrigerant recovery is when a technician removes refrigerant from a system and stores it in an external container. It is necessary to recover and remove the entire or maximum possible amount of refrigerant.

The refrigerant can be recovered in the liquid form or vapor form. It is necessary to recover both liquid as well as vapor refrigerant from the system for complete recovery. Let us discuss this a bit more.

While recovering, liquid refrigerant is recovered from the liquid line in the system.

• Refrigerant is first recovered in the liquid form for faster recovery.

• As refrigerant oil is mixed with refrigerant, liquid recovery causes loss of refrigerant oil.

After liquid recovery, the remaining refrigerant is recovered in vapor form. Vapor recovery is slow & consumes more time. So to save time, the recovery process is started by removing the liquid part first.

While recovering, vapor refrigerant is retrieved from the vapor line in the system.

• A lower amount of refrigerant oil is mixed with the vapor as compared to liquid refrigerant.

• So vapor recovery minimizes the loss of refrigerant oil from the system during recovery.

Recall that atmospheric pressure is the pressure of the surroundings. Sometimes, leaks in the appliance cause air to leak inside during recovery, and a complete recovery cannot be made. In such cases, recovery from the appliance is only possible till atmospheric pressure.

2. Recovery Time

Recovery time is the time it takes to recover a refrigerant. Generally, we want to recover refrigerant in the least possible amount of time.

Recall the factors affecting the time it takes to recover refrigerant:

1. Ambient Temperature, and

2. Hose Length

We will learn about two more techniques to speed up recovery:

1. Liquid Recovery

2. Recovery Tank Temperature

As already discussed, liquid recovery is faster and reduces the recovery time. Recall that the pressure inside the liquid side is higher. The higher pressure pushes the liquid out of the system into the recovery tank more quickly.

Recall that the pressure and temperature of any substance are directly related to each other. Cooling the tank reduces the temperature and pressure inside it.

Low pressure inside the recovery tank,

• Creates more space inside the tank and

• Reduces the resistance to refrigerant flow.

This leads to a quicker recovery.

3. Conclusion

In this module, we discussed the different refrigerant recovery methods. We also learned a couple of techniques for faster recovery.

Question #1: Recovering refrigerant from a system in the liquid phase will cause the loss of which of the following?

1. Water

2. Oil

3. Refrigerant

4. Non-condensables

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Refrigerant oil is mixed with liquid refrigerant in high quantities. During liquid recovery, the oil is recovered along with the refrigerant. This refrigerant oil is lost and can’t be filtered back.

Question #2: After the refrigerant liquid has been recovered from the appliance, any remaining vapor is;

1. purged to the atmosphere.

2. isolated in the appliance.

3. pumped into an appliance receiver.

4. removed by the recovery system.

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After liquid recovery, vapor refrigerant in the system should also be recovered using the recovery equipment.

Question #3: A technique to speed up the recovery process is;

1. Use a plastic recovery tank.

2. Cool the recovery cylinder.

3. Use a four-stage vacuum pump.

4. Heat the recovery cylinder.

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Cooling the recovery cylinder reduces the pressure inside it. This creates more space inside the tank and reduces the resistance to refrigerant flow, leading to a quicker recovery.