Craine Air Conditioning replaced an existing 30-ton Carrier R22 chiller with two new 15-ton Samsung R32 chillers. The project also included a full upgrade of the control system, replacing all existing controls with two new Honeywell temperature and static pressure sensors each serving their own air handler (equipped with a hot water/chilled water coil), and installing a new zone controller interface to manage 12 individual zones throughout the building. In addition, 12 new Belimo actuators were installed and connected to the existing dampers. The system was further enhanced with the installation of a Tekmar smart boiler controller and pump sequencer, optimizing boiler performance and energy efficiency.
The Honeywell static pressure sensors control a VFD for the fan motor at each air handler. Depending on the cooling/heating load of the building. The Honeywell temperature sensors control a modulating chilled water/hot water actuator by taking the supply/return temperature of the water entering/existing the air handlers coil. A new interface panel was designed and installed to control the Belimo actuators for each zone. The interface panel is in series with 12 thermostats. When there is call for cooling/heating the thermostats energize relays in the interface panel which send voltage to the actuators, opening them. The Tekmar smart boiler controller/pump sequencer was installed to maximize boiler efficiency and performance. The Tekmar controller also has a “warm weather shutdown mode” which automatically shuts the chillers off when the ambient temperature falls below 55 degrees.