AERCO BMS II BOILER - Manual (Page 31)

INSTALLATION
2-19
NOTE
The state of the SYS START, FLT ALARM and AUX Relays are
controlled by options contained in the Relay Menu described in
Chapter 3, paragraph 3.11.
System Start Relay
The state of the System Start (SYS START) relay contacts are controlled by the value set for the SYS
START TEMP and SYS START OPTION in the Relay Menu. The contacts are closed either when the
outdoor air temperature is less than the System Start Temperature (SYS START TEMP) or when there is
a load, or both. The default value for this temperature setting is 70°F. See paragraph 4.5 for additional
information.
Fault Alarm Relay
The state of the Fault Alarm (FLT ALARM) relay contacts are controlled by the option selected for the
FAULT ALRM RELAY, FAULT ALARM BLR and FAULT ALRM CLEAR in the Relay Menu. Contact
closure can be set to: ALL FAULTS, NO INTERLOCK, INTERLOCK 2 or INTERLOCK 1. The default for
this option is ALL FAULTS.
Auxiliary Relay
The state of the Auxiliary (AUX) relay contacts are controlled by the AUX RELAY CLOSE and AUX
RELAY OPEN options selected in the Relay Menu. Contact closure can be set to occur either when all
available boilers are at the 100% Fire Rate or for either when all boilers are at 100% Fire Rate or no
boilers are available (all boilers faulted or turned off).
2.13 4 – 20 MA WIRING
The BMS II can accept a remote 4 – 20 mA current signal representing a setpoint. This input is fused
internally at 0.63A. Connect the signal leads to the 4-20 + and 4–20 – terminals. Refer to Chapter 4,
paragraph 4.3 for Remote Setpoint programming using a 4 -20 mA input.