Which endorsement is necessary for a contractor to install and service equipment using the refrigeration cycle with lower than group one refrigerants?

The endorsement required for a contractor to install and service equipment using refrigeration cycles with refrigerants that fall into categories lower than group one is the combination of #4 Refrigeration and #7 Limited Refrigeration Service.

The #4 Refrigeration endorsement is specifically designed for individuals who work with refrigeration systems, encompassing both the installation and maintenance of equipment that utilizes these lower refrigerants. The #7 Limited Refrigeration Service endorsement permits work on specific types of refrigeration equipment that do not require comprehensive licensing for more hazardous refrigerants. Therefore, having both allows the contractor to legally engage in the practices related to these systems.

Other combinations in the options provided do not align with the regulatory requirements for servicing equipment with lower than group one refrigerants, either including unnecessary endorsements or lacking the appropriate licensing designation for the work intended. For example, Unlimited Refrigeration Service endorsements are generally aimed at higher categories of refrigerants, which would not apply in this scenario.