5.3 Evacuation Requirements and Levels
Key Takeaways
- Evacuation is required before any system is opened for service or disposal
- Very high-pressure = 0 psig; High-pressure = 0 psig (10" Hg vacuum); Low-pressure = 25 mm Hg absolute
- November 15, 1993 is the key date dividing old vs. new equipment evacuation requirements
- If required levels cannot be reached, evacuate to the lowest achievable level without contaminating refrigerant
- The final person in the disposal chain is responsible for ensuring recovery was completed
5.3 Evacuation Requirements and Levels
Before opening a system for maintenance, service, repair, or disposal, technicians must evacuate the system to specific vacuum levels. These requirements are among the most commonly tested topics on the EPA 608 exam.
Why Evacuation Is Required
Evacuation serves two purposes:
- Compliance: Federal law requires refrigerant recovery before opening systems
- System Protection: Removes moisture and non-condensable gases that damage system components
Required Evacuation Levels
The required evacuation level depends on the type of equipment, charge size, and equipment manufacturing date.
Equipment Manufactured ON OR AFTER November 15, 1993
| Appliance Type | Charge Size | Required Evacuation |
|---|---|---|
| Very high-pressure (e.g., R-410A, R-507A) | Any | 0 psig |
| High-pressure (e.g., R-22, R-404A, R-134a) | Less than 200 lbs | 0 psig (10 inches Hg vacuum) |
| High-pressure | 200 lbs or more | 0 psig (10 inches Hg vacuum) |
| Low-pressure (e.g., R-11, R-123) | Any | 25 mm Hg absolute |
Equipment Manufactured BEFORE November 15, 1993
| Appliance Type | Charge Size | Required Evacuation |
|---|---|---|
| Very high-pressure | Any | 0 psig |
| High-pressure | Less than 200 lbs | 0 psig (4 inches Hg vacuum) |
| High-pressure | 200 lbs or more | 0 psig (4 inches Hg vacuum) |
| Low-pressure | Any | 25 inches Hg vacuum |
Important Evacuation Notes
For very high-pressure appliances: Must be evacuated to 0 psig — atmospheric pressure. You cannot discharge very high-pressure refrigerant above atmospheric pressure.
For high-pressure appliances: Must reach 0 psig (or specified vacuum levels with older equipment).
For low-pressure appliances: Must reach 25 mm Hg absolute (with newer equipment) — this is a very deep vacuum because low-pressure systems normally operate below atmospheric pressure.
When Required Levels Cannot Be Achieved
If the evacuation levels in the tables cannot be achieved due to leaks or equipment limitations, the technician must:
- Isolate the leak if possible
- Evacuate the appliance to the lowest level that can be achieved without substantially contaminating the refrigerant
- For high/very high-pressure: must not exceed 0 psig before opening
- For low-pressure: must not exceed 0 psig before opening
Special Circumstances
System mothballing (extended shutdown):
- If a system will be idle for an extended period but not opened, refrigerant may be left in the system
- However, if opened, normal recovery requirements apply
Disposal of appliances:
- Must recover refrigerant before disposal
- Same evacuation requirements apply whether equipment is being serviced or disposed of
- The final person in the disposal chain is responsible for ensuring recovery was completed
For the Exam: Memorize the evacuation levels: very high-pressure = 0 psig; high-pressure = 0 psig (10" Hg vacuum); low-pressure = 25 mm Hg absolute. Know the difference between requirements for equipment made before vs. after November 15, 1993.
What is the required evacuation level for a high-pressure system containing less than 200 lbs of refrigerant (equipment made after November 15, 1993)?
What is the required evacuation level for low-pressure equipment (manufactured after November 15, 1993)?
What date distinguishes "old" vs. "new" recovery equipment and evacuation requirements?