Enertech Global
78
EAV - EME/EMD Rev. A Models
Installation and Operations Manual
Control Boards
Human Machine Interface (HMI). Touch screen user interface
where current status can be observed and settings of the system
can be changed, described in additional detail in this section.
This is the master controller which communicates via RS-485
with the ASB and outdoor unit.
Field Wiring and RS-485
The field wiring blocks provide dry contact inputs for connection
to zone controllers (see Section 8). These inputs provide calls for
Heating, Cooling, High Heating, and Hot Water.
Actuator Sensor Board (ASB)
The ASB is a secondary controller to the HMI (primary controller)
and provides inputs for sensors and outputs to actuators for
the Indoor Module. The inputs include thermistors, flow meter,
and pump feedback. It controls actuators, including pump speed
(via PWM), electric heater stages, and the three way valve.
24VAC from the transformer is fed into the ASB for use on these
outputs.
ASB Companion Board
The Companion Board is an IO expander for the ASB. The
dry contact inputs on the field wiring in input into this board.
Additionally, it provides stable 12VDC supply for the ASB and
HMI from input line voltage.
Thermistors
Two thermistors are utilized on the Indoor Module to measure
entering and leaving load temperatures. Through these
measurements the temperature difference (Delta-T) is calculated
and provides the ideal pump speed. Reference Section 12 for
resistance values.
Flow Sensor
The flow meter provides an accurate measurement of GPM
through the load circuit. It is used for modulation of pump,
ensuring minimum flow in all conditions. They are also used for
simple readouts on the HMI as well as flow faults and alarms.
User Interface
Touch screen user interface where current status can be
observed and settings of the system can be changed. This is the
master controller which communicates via RS-485 with the ASB
and outdoor unit.
Startup Wizard
The Startup Wizard is part of the First Run Setup. This Wizard
is designed to ensure that the system has the proper flow rates
and that air is purged from this system. Screens from the Startup
Wizard are shown on the next page.
Section 9: On-Board Controls
