Because the new food production facility employees would use very potent chemical cleaning compounds to sanitize the facility, thermostat installation presented a challenge. The walls of the food service facility are sprayed down each night with a cleaning compound. A wall thermostat would be ruined by the solution. That's where the Lennox Network Control Panel (NCP) came in handy. The NCP is a direct digital controller system. Each of the units is equipped with a duct-mounted return air temperature sensor that ties into the NCP.
"One of the concerns about the unit controls was that Donelson didn't want anyone tampering with wall controls, but they wanted centralized unit control," Jones said. The NCP has the capability to network as many as 31 L Series units to one panel, and each unit can be individually monitored and adjusted from the central NCP. All of the units are wired to the NCP and controlled from one location.
The L Series unit comes with an Integrated Modular Control. The IMC is a combination rooftop controller and direct digital controller that works in conjunction with the NCP. The IMC diagnoses problems, giving an illuminated numeric code that pinpoints the trouble, while providing a diagnostic history, including the time and date the problem occurred. The IMC also relays this information to the NCP. From the NCP, the user can view problems and error codes, via a time- and date-stamped text message for all rooftop units from one central location.
Also because of the potent cleaning compound used within the facility, the evaporator coils needed Heresite coating on them. The cleaning compound would have corroded the standard aluminum coils. One other feature unique to the job was the concentric ductwork that the Lee Co. installed. With 14 five-ton L Series units and one three-ton Lennox L Series unit, the facility might have needed extra steel support structures, which would have added a considerable amount to the cost, according to those involved with the project. The concentric ductwork offered a more cost-effective air distribution package, they said.
The Lee Co. decided to go with the L Series, in part because of cost effectiveness, Jones said.
Publication date: 07/23/2001