Last month, I began the discussion of the impact of more and more HVAC equipment being provided with manufacturer-designed and factory-installed controllers. We recently commissioned a new building with ground-source water-to-water heat pumps in their central plant in lieu of boilers and chillers. The heat pumps were provided with onboard controllers in a building otherwise monitored and controlled by a central BAS.
The project was designed and specified to have water-to-water heat pumps fully monitored and controlled by the BAS. During the submittal review process, the contractor offered a cost savings to the owner for removing the heat pumps from the BAS and having them controlled solely by onboard controllers. This “value engineering” proposal did not include an interface card for sharing heat pump points with the BAS, although there were a few standard contacts provided for alarms, status, and enable/disable. This proposal was not vetted by the full owner/designer/commissioning team before it was approved.