Watts AERCO Edge [ii] - Page 131

Edge [ii] Controller Operation Manual
SECTION 6 – ADVANCED SETUP
OMM-139_E • 8/25/2020 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 131 of 196
Manager or BST Client in Section 6.3.1: Cascade Configuration. The following parameters
appear only when the unit is configured as a BST Manager:
• BST Max Boilers: The maximum number of boilers that will fire. For example: if
there are 5 boilers, but this setting is set to 3, the plant will not fire more than 3 boilers.
(Range: 1 to 16)
• SH Valve Close Delay: The time an open Isolation Valve will remain open once a
boiler has been cycled off. When an ignited boiler is cycled off, its Isolation Valve will
remain open for the specified time to dissipate residual heat. (Range: 0 to 15)
3. The remaining parameters are available on both BST Manager and BST Client units. They
are available depending on the Application chosen in Section 6.3.3: BST Application
Configuration, as shown in the table below:
TABLE 6.12: Sequencing Control Parameters
Available Parameters
Current BST Application
SH
DHW
Other
SH+DH
W-2-Vlv
SH+DH
W-1-Vlv
SH+DH
W-Stpt
Prty
Other+SH-
Stpt Prty
Other+DHW
-Stpt Prty
Low Flow Mode
✓
✓
✓
✓
✓
✓
✓
✓
Low Flow Threshold
✓
✓
✓
✓
✓
✓
✓
✓
SH Next On Valve Pos
✓
✓
✓
✓
✓
✓
✓
✓
SH Next Off Valve Pos
✓
✓
✓
✓
✓
✓
✓
✓
SH BST Fire Rate Up
✓
✓
✓
✓
✓
✓
✓
✓
SH High-Fire Fire Rate
✓
✓
✓
✓
✓
SH Low-Fire Fire Rate
✓
✓
✓
✓
✓
DHW High-Fire Fire Rate
✓
✓
✓
✓
✓
✓
✓
✓
High Fire Threshold Timer
✓
✓
✓
✓
✓
DWH Pump Off Time
✓
✓
✓
DHW BST Fire Rate Up
✓
✓
✓
• Low Flow Mode: Choose Off, On - Outlet Temp or On - Avg Temp. If either “On”
option is chosen, BST monitors the multi-boiler system to detect if a “low-flow”
condition exists. If it does exists, BST slowly shuts down one boiler at a time in an
attempt to raise the Fire Rate of the remaining boilers. If the low-flow condition
persists, and only a single boiler remains ignited, BST will use the “Outlet Temperature
Sensor” of the remaining ignited boiler to control the temperature. The Outlet
Temperature Sensor is mounted in the individual boiler and drastically increases the
response time to precisely control temperature.
• Low Flow Threshold: For low flow applications, this parameter allows the boiler to
operate without excessive cycling. This parameter specifies the valve position below
which the boiler plant will enter this mode (Range: 10% to 35%, default = 25%).
• SH Next On Valve Pos: Determines the valve position that triggers the next SH
(Space Heating) unit to come on line. (Range: 16% to 100%)
• SH Next Off Valve Pos: Determines the valve position that triggers the next SH
(Space Heating) unit to come off line. (Range: 16% to 100%)