EPA 608 Core Chapter 2 (Take full course for free)
In this module, we will take a look at the properties of equipment used in HVAC systems.
1. Objective
In this module, we will take a look at the properties of equipment used in HVAC systems.
Earth’s atmosphere is made up of several layers, as shown.
Ozone is found in the lowest two layers of Earth’s atmosphere, the Troposphere and the Stratosphere.
2. Appliance Pressure
We look at the pressure of the refrigerant in liquid phase to decide what level of pressure the appliance operates at.
The levels of pressure in appliances can be categorized into three types:
High
Medium
Low
A refrigerant’s pressure is determined by the pressure of the appliance it is in. For example, a refrigerant used in a low pressure appliance would be a low pressure refrigerant. This is how we classify the pressure of refrigerants according to Section 608 regulations.
Examples of refrigerants used in high pressure appliances include:
R-22
R-407c
R-410a
R-502
Any one of these is considered a high pressure refrigerant.
Examples of refrigerants used in medium pressure appliances include:
R-12
R-134a
R-500
Any one of these is considered a medium pressure refrigerant.
Examples of refrigerants used in low pressure appliances include:
R-11
R-123
R-113
Any of these would be considered a low pressure refrigerant.
3. Recovery Devices
Recall that recovering is when refrigerant is removed from a system and stored in a container.
There are two main types of recovery
System Dependent Recovery
Self-Contained Recovery
The type of device used depends on what type of recovery the technician is performing.
System dependent recovery is kind of how it sounds. The recovery process dep
ends on the system. This process of recovering uses the pressure of the compressor to recover the refrigerant. Hence “system dependent”.
Recall that refrigerant will flow from high pressure to low pressure. This is similar to how heat will flow from high temperature to low temperature, like from your hot, steaming mug to the surroundings.
So the compressor is in high pressure. If you connect the compressor to a low pressure container, refrigerant will naturally flow from the high pressure compressor to the low pressure recovery device. This is system dependent recovery. It depends on the compressor’s pressure.
Let’s say you are using a recovery device that uses this method of system dependent recovery. Then your recovery equipment or device is labeled a system dependent device.
Self-contained recovery is the opposite. It does not rely on the pressure of the compressor or any internal components.
Self-contained recovery is the opposite. It recovers refrigerant without relying on the pressure of the compressor or any internal components.
4. Conclusion
In this module, we discussed how to classify appliances based on their pressure. We also defined different types of recovery devices.