The injunction had been requested by the State Board of Examiners of Plumbing, Heating and Fire Sprinkler Contractors, The Associated Press reported.
Carbon monoxide from the swimming pool heating system infiltrated a room on the floor above at the Best Western Plus Blue Ridge Plaza and killed Daryl and Shirley Jenkins last April and 11-year-old Jeffrey Williams in June.
Superior Court Judge Donald Stephens issued the order against Appalachian Hospitality Management and three employees. The injunction said the defendants denied they had acted as contractors but agreed to go along with the consent order.
Damon Mallatere, who owned Appalachian Hospitality, was indicted in January on three charges of involuntary manslaughter and one charge of assault inflicting serious bodily injury. The boy's mother, Jeannie Williams, was also poisoned but survived.
Mallatere's company managed the hotel.
No trial date has been set.