Application (Field Installed)

GPEC BoilerControl

Boiler - Sequence of Operation

Note: The following is a sample of a typical sequence of operation that may be adapted for a particular project. This is provided as a suggestion on how to write a sequence of operation for a specific project. The boiler controller includes the ability for the operator to select some different sequences. Consult your Carrier representative if the sample sequence requires alterations.

4.7Boiler Controller- Sequence of Operation

A.Description:

1.General:
Each boiler shall be directly controlled and monitored by a EMS compatible dedicated stand-alone programmable logic General Purpose ElectronicController (GPEC). Controller logic system shall monitor boiler inlet (return) and outlet (supply) water temperatures.Controller’s digital or analog output(s) shall directly control boiler stages.

2.Sequence:
During system operation, enable multi-staged (electric or gas fired) boiler. As heating load increases, (as sensed by boiler supply and return water sensors) logic controller stages boiler elements on-line to maintain operator’s terminal setpoint (adjustable). As heating load decreases, controller stages boiler elements off-line.

3.Boiler control algorithms shall be kept in non-volatile EEPROM at the controller. Logic Controller, working with associated water sensors and boiler staging, shall maintain boiler functions independent of other control equipment.

4.Standard factory logic control sequences shall be available for loading into controllerEEPROM. Logic sequences shall be field modifiable to provide any necessary site customizations. Factory control programs shall be proportional plus integral type, maintaining maximum accuracy and stability. Controller shall be programmable, either locally or over the EMS network. Controller communicates on EMS bus.

5.Provide temperature sensors (in sensor wells) at boiler inlet and outlet.

6.High and low temperature alarms shall be generated when operator’s terminal alarmsetpoints are not met.

7.Commands/Displays:
Provide for boiler, the following commands/displays at operator’s terminal:

  1. Manal/auto (scheduled) enable.
  2. Number of boiler heating stages active (or % ON indication).
  3. Boiler supply water temperature setpoint.
  4. Boiler inlet water temperature indication.
  5. Boiler outlet water temperature indication.
  6. Alarm status (high or low temperature setpoints).
  7. Boiler runtime totalization.
  8. Boiler trendlogs.
  9. Alarm history.

8.Standard factory logic control sequences shall be supplied for loading into controller EEPROM. Logic sequences shall be field modifiable to provide any necessary sitecustomizations. Factory control programs shall be proportional plus integral type, maintaining maximum accuracy and stability. Controller shall be programmable, either locally or over the EMS network. Controller communicates on theEMS bus.