Specifications include, but are not limited to: The hot water system consists boiler plant, containing 2 existing system pumps and 2 new modulating boilers with BACNet Interfaces. The BMS controller shall provide stand-alone control interfaced with existing BMS workstation control. The following is sequence of operation: 2. Heating System Enable/Disable: a) The heating system shall be enabled when the outside air temp. falls below 60.0 deg. F (adj.) When enabled, the BAS controller shall start the existing lead hot water pump, the lead boiler circulating pump, and enable the lead boiler. The boiler factory control shall operate the boiler to maintain its local supply setpoint. b) Heating shall be disabled when the outdoor air temperature is above 65.0 deg. F (adj.). When heating is disabled, the hot water pumps and boilers shall be commanded to OFF. 3. Boiler Control: a) The boiler lead/lag sequence shall be based on a weekly schedule. From the BMS workstation, an operator shall be able to manually change the lead/lag sequence. b) A heating system enable point shall be enabled based on outside air temperature ("on" below 65°F adj.) If the heating system enable point is on, the lead boiler shall be enabled and its respective circulation pump shall start.
