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Equipment and Components

EPA 608 Core Chapter 30(Take full course for free)


In this module, we are going to take a look at the different types of equipment used to service HVAC systems.


1. Manifold Gauge Set


A manifold gauge is a tool commonly used by technicians to service HVAC equipment. It is used to measure pressures and temperatures of the system. Another name for manifold gauge is service manifold.


In the center of the manifold gauge set is the yellow hose, which is center port. The yellow hose is used for evacuation, recovering, and charging.

Color coding on the manifold gauge means the following:

  • Blue Gauge - Low Pressure side

  • Red Gauge - High Pressure side

The high pressure side (color coded red) of the service manifold shows a range of pressure from

  • 0 to 800 psi

The low pressure side (color coded blue) of the service manifold shows pressure in units of:

  • Psig, and

  • inHG (inches of Mercury

2. Process Stub


If a piece of equipment contains CFC or HCFC refrigerants, Section 608 requires that it has a process stub.

A process stub is a usually straight piece of tubing that provides access to refrigerant inside an appliance. The process stub is resealed at the end of a technician’s service.


The purpose of a process stub is to make it easier to recover refrigerant. This is also called a service aperture.


3. Relief Valves


In order to make sure that the system is completely safe to use, we need to replace any components that show danger of failing. This way, we prevent major failures that can create life threatening situations. Safety is always first.

Relief valves are installed to provide insurance in case pressure builds up in the system. If is too high because of irregularities in the system, this can cause major explosions. This is a major safety concern.


If the body of relief valves show any sign of corrosion, the relief valve must be replaced. Corrosion on the body indicates damage that may prevent the relief valve from doing its job to regulate pressure.


4. Conclusion


In this module, we looked at the different types of equipment we commonly used. We discussed conventions, procedures, and specific properties of devices we use in this trade.


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