Residents on stretchers were removed first, followed by those in wheelchairs, from Advanced Nursing and Rehabilitation at 169 Davenport Avenue.
Ambulances were lined up on the street outside the facility. No injuries were reported during the evacuation. A total of 185 residents were evacuated.
According to the Connecticut Association of Health Care Facilities, the facility treats people with memory loss, brain injury and provides hospice care.
Officials said a sprinkler burst over the main electrical panel and building officials said the facility was evacuated because it could take several hours to repair the problem.
Mayor Toni Harp says the home will have to be closed for two days. Some residents will stay with family members.
City emergency management officials say some patients will be sent to homes elsewhere, including Meriden, Milford, Wallingford and Hartford.