There's a problem with the HVAC system at the Junior and Senior high school in Newmarket, and it's making a high pitched squeal. This wing of the school was built in 1924, and Principal Christopher Andriski says the exposed pipes and vents make this screeching sound all the time. The noise, he says, is the system’s way of alerting the custodian. "He's gotta manually push a button up there," Andriski explains.
http://nhpr.org/post/no-help-state-newmarket-and-other-towns-grapple-going-solo-school-construction
