Troubleshoot, repair, and maintain residential HVAC systems, including heat pumps, split systems, single package vertical units (SPVUs), mini-splits, tankless water heaters, and other small residential units. South Oxford uses E-Verify , a web-based system that allows enrolled employers to confirm the eligibility of their employees to work in the United States through the U.S. Department of Homeland Security and the Social Security Administration, where permitted by state law.