Notes:
1. After a Modbus communication failure, while using the Modbus connection to monitor or control
the boilers, the ‘Comm Failure’ alarm is not cleared until a successful write to both the Remote On
/ Off Modbus Command (00004) and Remote Firing Rate or Remote Setpoint (40006) points have
been completed, power is cycled or the ‘Protocol’ parameter is changed from Modbus to Peer-to-
Peer and back again.
2. The limit string points (00006 - 00011) are only monitored when there is a Call For Heat.
Additionally, if one of these items is ‘open’ items down stream are not monitored.
3. The boiler "state" points (00020 - 00032) are mutually exclusive (i.e. only one is asserted at a
time). This will reflect the state of the message on the front of the boiler. Refer to page 6 for an
explanation of each state.
4. The “Annunciated” points (00033 – 00046) reflect the state of the signals used to control the
displayed Alarm Message. Refer to pages 36 & 37 for an explanation of each annunciator point.
5. “General Alarm” point (00015) turns “On” when the boiler is indicating any alarm condition.
To establish a Modbus network set the following parameters:
Communication Menu:
Protocol = Modbus
Modbus Address = Give each boiler a unique address.
Baud Rate = Set identical to remote system.
Parity = Set identical to remote system.
Connect all boilers using a RJ11 ended telephone cable.
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