SAN DIEGO, CA-In three separate transactions valued at a combined $8.3 million, a total of 55 apartment units have sold recently in San Diego County. The largest of the three deals involves a 42-unit property located at 710 N. Quince St. in Escondido. Private investor James T. Shen of Beverly Hills has acquired the asset, known as Quince Park, from Spring Valley-based Petakovich Family Trust. Patrick J. Doyle of the San Diego office of Hendricks & Partners brokered the $4.5-million transaction.Doyle also negotiated the recent sale of nine units in a separate transaction in Vista. The complex, known as Tiffany, has sold to Khoi Dunh Hoang and Ky Thi Nguyen of Escondido. The buyers have paid $1.1 million to sellers Robert Miller of San Marcos and Murray Greengrass of Lemon Grove for the property, which is located at 665 W. California Ave. in Vista.Separately, 531 Partners LLC has picked up a Del Mar apartment asset for $2.7 million. The complex, which stands at 531-543 Camino Del Mar, is comprised of four units that each house two bedrooms and two-and-a-half bathrooms and encompass 1,575 sf. Glenn Karp and Tony O’Neill of Coldwell Banker Commercial-Towne Center acted on behalf of both 531 Partners LLC and the seller, Ruth A. Stolzenberg Trust and M. Lon Marsh Family Trust.