Specifications

MODBUS COMMUNICATION MANUAL
A-3
Table A-1. Status and Fault Messages –Cont.
Code MESSAGE DESCRIPTION
17 IGN SWTCH OPEN
DURING IGNITION
The Ignition Position Limit switch on the Air/Fuel valve opened
during ignition.
18 AIRFLOW FAULT
DURING IGN
The Blower Proof Switch opened during ignition.
19 AIRFLOW FAULT
DURING RUN
The Blower Proof Switch opened during run.
20 SSOV FAULT
DURING IGN
The SSOV switch closed or failed to open during ignition.
21 SSOV FAULT
DURING RUN
The SSOV switch closed for more than 15 seconds during run.
22 FLAME LOSS
DURING IGN
The Flame signal was not seen during ignition or lost within 5
seconds after ignition.
23 FLAME LOSS
DURING RUN
The Flame signal was lost during run.
24 HIGH EXHAUST
TEMPERATURE
The High Exhaust Temperature Limit Switch is closed.
25 LOSS OF POWER A power loss occurred. The time and date when power was
restored is displayed.
26 LOSS OF SENSOR Not Currently Used
27 LOSS OF SIGNAL Not Currently Used
28 HIGH O2 LEVEL Not Currently Used
29 LOW O2 LEVEL Not Currently Used
30 HIGH CO LEVEL Not Currently Used
31 SSOV RELAY
FAILURE
A failure has been detected in one of the relays that control the
SSOV.
32 RESIDUAL
FLAME
The Flame signal was seen for more than 60 seconds during
standby.
33 HEAT DEMAND
FAILURE
The Heat Demand Relays on the Ignition board failed to
activate when commanded.
34 IGN SWTCH CLOSED
DURING PURGE
The Ignition Position Limit switch on the Air/Fuel valve closed
during purge.
35 PRG SWTCH CLOSED
DURING IGNITION
The Purge Position Limit switch on the Air/Fuel valve closed
during ignition.
36 SSOV
SWITCH OPEN
The SSOV switch opened during standby.
37 IGNITION BOARD COMM
FAULT
Communication fault between the Ignition board and the CPU
board.
38 WAIT Prompts the operator to wait.