Benchmark 2.0 LN Installation, Operation & Maintenance Manual
CHAPTER 5 – MODE OF OPERATION
Page
68
of
168
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0046_0J
06/18/2015
Phone: 800-526-0288
GF-123
MENU OPTION
SETTING
Boiler Mode
Direct Drive
Remote Signal
BMS (PWM Input) or
Network (RS485)
Refer to paragraph 3.3 for instructions on changing menu options.
5.6.1 BMS External Field Wiring
Wiring connections for BMS control using PWM signaling are made between connector JP2 on
the BMS panel (boilers 1 through 8), and the B.M.S. (PWM) IN terminals in the I/O Box on the
front of the boilers. Refer to the wiring diagram provided on the cover of the I/O Box.
Wiring connections for RS485 Modbus control are made between connector JP11 on the BMS
(boilers 9 through 40) or JP6 on BMS II/ACS (boilers 1-32) and the RS485 COMM terminals in
the I/O Box on the front of the boilers.
Wire the units using shielded twisted pair wire between 18 and 22 AWG. Observe the proper
polarity for the B.M.S. (PWM) IN and/or RS485 COMM wiring connections. Shields should be
terminated only at the BMS/BMS II/ACS and the boiler end must be left floating. Each unit’s
wiring must conform to the above.
5.6.2 BMS Setup and Startup
This mode of operation is factory preset and the AERCO BMS/BMS II/ACS controls the firing
rate (air/fuel valve % open position). There are no setup instructions for each individual unit.
To operate the unit in manual mode, press the
AUTO/MAN
switch. The
REMOTE
LED will go
off and the
MANUAL
LED will light
To change back to the BMS mode, simply press the
AUTO/MAN
switch. The
REMOTE
LED
will again light and the
MANUAL
LED will go off.
5.7 COMBINATION CONTROL SYSTEM (CCS)
NOTE
Only the BMS and ACS can be utilized for the Combination Mode,
but not the BMS II.
A Combination Control System (CCS) is one that uses multiple boilers to cover both space-
heating and domestic hot water needs. An AERCO Boiler Management System (BMS) Model
168 and a Combination Control Panel (CCP) or an ACS and an ACS Relay Panel (optional,
depending on applications) are necessary to configure this system. Typically, an adequate
number of boilers are installed to cover the space-heating load on the design day, however one
or more units are used for the domestic hot water load.
The theory behind this type of system is that the maximum space-heating load and the
maximum domestic hot water load do not occur simultaneously. Therefore, boilers used for the
domestic hot water are capable of switching between constant setpoint and BMS modes of
operation. These boilers are the combination units and are referred to as the combo boilers. The