Section 7: Boiler Sequencing Technology; Introduction - Watts AERCO Benchmark BMK5000 Operation And Service Manual

Benchmark Platinum-Edge [ii]: Operation-Service Manual
SECTION 7 – BOILER SEQUENCING TECHNOLOGY

SECTION 7: BOILER SEQUENCING TECHNOLOGY

7.1 INTRODUCTION

The Boiler Sequencing Technology system (BST) is an integrated 16 boiler control system. It is
built into the Edge Controller. It has its own sophisticated PID control system designed to
simultaneously control the light off and modulation of up to 16 boilers while achieving
maximum operational efficiency.
BST is designed to ensure that all Boilers in the system operate at maximum efficiency. This is
accomplished by lighting off boilers only when all ignited boilers reach or exceed a defined
Valve Position (Fire Rate). Operating all boilers below the defined Fire Rate "Next on VP" (for
Next Turn on Valve Position) insures that they are firing at their most efficient Fire Rate. One
unit the BST network is defined as the "Manager" and all other units on the network are defined
as "Client" units. The Manager monitors the system Header Temperature, and also monitors all
Client unit's status information, efficiently controlling all units in order to achieve and maintain
the required BST Setpoint Temperature.
When there is a demand, the Manager will light off the lead boiler based on the BST
Sequencing selection in the BST Cascade Status screen. As system load increases and the
valve position of the ignited unit(s) reach the Next on VP (% valve position), the Manager will
light off the next available unit. A simplified block diagram of multiple Boilers connected to a
BST is shown in Figure 7-1 below.
NOTE:
After the boiler load is satisfied, the isolation valve remains open for a programmed interval
(default = 2 minutes) before closing. When the system load is satisfied, the Edge Controller
will open the isolation valves for all the boilers. The BST controls the valves via a 0-20 mA
signal (see Section 2.11.1: I/O Board Connections in the Benchmark Platinum-Edge:
INSTALLATION Manual (GF-210)).
OMM-0137_J •
12/20/2022
Figure 7-1: Simplified BST Block Diagram
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
NOTE: Use either FFWD Header Temp
Sensor or Modbus Header Temp Sensor
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