8
-
8
TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION
PROBABLE CAUSES
CORRECTIVE ACTION
INTERLOCK
OPEN
1. Interlock jumper not installed or
removed
2. Energy Management System does
not have boiler enabled.
3. Device proving switch hooked to
interlocks is not closed.
1. Check for a jumper properly installed across the interlock
terminals in the I/O box
2. If there are two external wires on these terminals check any
Energy Management system to see if they have the units
disabled (a jumper may be temporarily installed to see if the
interlock circuit is functioning).
3. Check that proving switch for any device hooked to the interlock
circuit is closing and that the device is operational.
LINE VOLTAGE
OUT OF PHASE
1. Line and Neutral switched in AC
Power Box.
2. Incorrect power supply transformer
wiring.
1. Check Line (hot) and Neutral in AC Power Box to ensure they
are not reversed
2. Check transformer wiring, in AC Power Box, against the power
box transformer wiring diagram to ensure it is wired correctly
LOW GAS
PRESSURE
1. Incorrect supply gas pressure.
2. Defective Low Pressure Gas Switch
1. Measure gas pressure upstream of the supply gas regulator with
the unit firing. Ensure it is at least 3.5” W.C. for FM gas train, or
4.0” W .C. for IRI gas train. Max. allowable pressure is 2 psig
(see para. 2.7.1).
2. Measure gas pressure at the low gas pressure switch. If it is
greater than 2.6” W.C., measure continuity across the switch
and replace if necessary.
LOW WATER
LEVEL
1. Insufficient water level in system
2. Defective water level circuitry.
3. Defective water level probe.
1. Check system for sufficient water level.
2. Test water level circuitry using the Control Box front panel LOW
WATER TEST and RESET buttons. Replace water level
circuitry if it does not respond.
3. Check continuity of probe end to the shell, change probe if there
is no continuity.
MODBUS COMM
FAULT
1. Boiler not seeing information from
Modbus network
1. Check network connections. If fault persists, contact qualified
Service Personnel.
PRG SWTCH CLOSED
DURING IGNITION
1. A/F Valve rotated open to purge and
did not rotate to ignition position
1. Start the unit. The Air/Fuel Valve should rotate to the purge
(open) position, then back to ignition position (towards closed)
during the ignition cycle. If the valve does not rotate back to the
ignition position, check the Air/Fuel Valve calibration. If
calibration is okay, the problem may be in the Air/Fuel Valve or
the Control Box. Refer fault to qualified service personnel.
Summary of Contents for Benchmark 3.0LN Series
Page 6: ...iv ...
Page 8: ...B ...
Page 42: ...INITIAL START UP 4 8 ...
Page 80: ...A 6 ...
Page 84: ...B 4 ...
Page 86: ...C 2 APPENDIX C ...
Page 93: ...APPENDIX F APPENDIX F F 1 ...
Page 94: ...APPENDIX F F 2 ...
Page 95: ...APPENDIX F F 3 ...
Page 96: ...APPENDIX F F 4 ...
Page 97: ...APPENDIX F F 5 ...
Page 98: ...APPENDIX F F 6 ...
Page 99: ...APPENDIX F F 7 66034 ...
Page 100: ...APPENDIX F F 8 ...
Page 101: ...APPENDIX F F 9 ...
Page 102: ...APPENDIX F F 10 ...
Page 103: ...APPENDIX F F 11 ...
Page 104: ...APPENDIX F F 12 ...
Page 105: ...APPENDIX F F 13 ...
Page 106: ...APPENDIX F F 14 ...
Page 107: ...APPENDIX G APPENDIX G G 1 ...
Page 108: ...APPENDIX G G 2 ...
Page 109: ...APPENDIX G G 3 ...
Page 110: ...APPENDIX G G 4 ...
Page 111: ...APPENDIX G G 5 ...
Page 112: ...APPENDIX G G 6 ...
Page 113: ...APPENDIX H APPENDIX H H 1 ...
Page 114: ...APPENDIX H H2 ...
Page 115: ...APPENDIX H H 3 ...
Page 116: ...APPENDIX H H 4 ...
Page 117: ...APPENDIX H H 5 ...
Page 118: ...APPENDIX H H 6 ...
Page 119: ...APPENDIX H H 7 ...
Page 120: ...APPENDIX H H 8 ...
Page 122: ...APPENDIX I I 2 ...
Page 126: ...NOTES ...
