Boiler Controls; Temperature Control Modes - Watts Aerco AM Series Operation & Maintenance Manual

AM Series Pool Heater User Manual
CHAPTER 2: FUNCTION & SPECIFICATIONS

2.3 Boiler Controls

AM Series pool heater units must be controlled in one of two ways: either through an external
AERCO controller, or be controlled through a Building Automation System (BAS). The boiler is
comprised of an internal controller coordinating individual thermal module controllers linked as
slaves, and these controls are fully field adjustable while the boiler is in operation by either the
external controller or the BAS. The boiler features an LCD display for monitoring of all sensors
and interlocks. Each of the thermal module controllers consists of a combustion safeguard and
flame monitoring system. Individual thermal module controllers are field replaceable. The
combustion safeguard/flame monitoring system utilizes spark ignition and a rectification type
flame sensor. The boiler control system reports and displays boiler & sensor status and includes
extensive self-diagnostic capabilities.
Each boiler incorporates dual over-temperature protection with manual reset and low water cut
out, both in accordance with ASME Section IV and CSD-1.

2.3.1 Temperature Control Modes

During boiler operation, the individual thermal module controllers vary their respective thermal
module's input throughout its full range to maximize the condensing capability of the boiler, and
operates with an Inverse Efficiency Curve, with known Part Load Value Efficiencies. There are
five (5) modes in which the AM boiler may be set, each one adjusting this performance according
to specific requirements.
The AM Series boiler(s) operates in the control modes listed below:
•
Internal Setpoint
•
Indoor/Outdoor Reset
•
0 to 10VDC Temperature Setpoint
•
Network Temperature Setpoint
A description of each selectable control mode follows:
• Internal Setpoint:
In this mode, the control of discharge water temperature is set through an internal setpoint
with an adjustment of between 68ºF to 189ºF. The individual thermal module controllers vary
their respective thermal module's input throughout its full range to maximize the condensing
capability of the water heater. The boiler operates to maintain a constant pool water
temperature.
• Indoor/Outdoor Reset:
In this mode, the boiler operates to vary pool water temperature setpoint on an inverse ratio
in response to outdoor temperature (measured by an external temperature sensor) to control
pool water temperature. The individual thermal module controllers vary their respective
thermal module's input throughout its full range to maximize the condensing capability of the
boiler.
• 0VDC to 10VDC Temperature Setpoint:
In this mode, the boiler operates to vary pool water temperature setpoint linearly as an
externally applied 0 VDC to 10 VDC signal is supplied to the E8 Controller.
• Network Temperature Setpoint:
In this mode, the boiler will operate to vary pool heater temperature setpoint as an external
communication utilizing the MODBUS protocol is supplied to the boiler's communications
module via the RS-485 port.
OMM-0111_B: • GF-146-P • 10/29/2019 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page 13 of 47