Watts AERCO Edge [ii] - Reserve Unit Control

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 135 of 196
2. In Select Output, choose either:
• Cascade Valve: For use with AERCO supplied valves.
• Aout 2: For controlling non-AERCO supplied valves.
3. The following parameters appear for both values of Select Output:
• Output Signal Type: Select the output signal type of the selected output: Current
or Voltage.
• Control Mode: Choose one: On/Off, Linear Modulation or Delta T Modulation.
• Valve Feedback: Choose Enabled or Disabled. If Enabled, the following additional
parameters appear:
o Valve Feedback Status: A read-only display of the current valve status.
o Valve Feedback Timer: The time to detect the Valve Feedback Status
(Range: 30 to 240 sec.)
• Valve Balancing: If you wish to implement the Valve Balancing feature on the
cascade, set this parameter to Enabled, then go to Section 6.3.4.8: Valve Balancing
and complete the instructions there.
• Min # Valves Open: This parameter appears only if Unit Mode = BST Manager
(see Section 6.3.1: Cascade Configuration). Specify the minimum number of isolation
valves that must stay open at all times, including during plant standby conditions. The
number specified appears on the Isolation Valve Status screen (see Section 7.5:
Isolation Valve Status). This ensures the boiler’s maximum flow is not exceeded at low
loads and helps reduce the flow rate during plant standby. To determine the value for
Min # Valves Open, use the following formula, rounding up the result to the higher
number:
Min # Valves Open = (Pump’s minimum flow rate / Boiler maximum flow rate).
4. The following parameters appear only if Select Output = Aout 2:
A. Open Vlv Control Signal: Select the signal that will “fully open” the valve: 0 mA,
4 mA or 20 mA.
B. Close Vlv Control Signal: Select the signal that will “fully close” the valve: 0 mA,
4 mA or 20 mA.
Reserve Unit Control
The Reserve Unit Control screen allows you to enable the Reserve Unit Control feature, which
will activate a “Reserve Unit” in the event the plant cannot keep up with the system load.
NOTE:
This screen is available only after BST Cascade functionality has been enabled (see the
Unit Mode parameter in Section 6.3.1: Cascade Configuration). If the unit is configured as
a BST Manager, its parameters apply to this unit and all BST Client units. If the unit is
configured as a BST Client, the parameters configured on the BST Manager will take
precedence.
1. Go to: Main Menu → Advanced Setup → BST Cascade → Operating Controls →
Reserve Unit Control.