AERCO BMK 2.0 LN Dual Fuel Serial G-11-2402 and UP - Manual (Page 88)

CHAPTER 8: TROUBLESHOOTING GUIDE
Page 88 of 160 PR2: 04/22/13
Benchmark 2.0LN Dual-Fuel Low NOx Boiler
Operation and Maintenance Manual
OMM-0052_0E
GF-127
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FAULT
INDICATION
PROBABLE CAUSES CORRECTIVE ACTION
HIGH WATER
TEMP
SWITCH OPEN
1. Faulty Water temperature switch.
2. Incorrect PID settings.
3. Faulty shell temperature sensor.
4. Unit in Manual mode.
5. Unit setpoint is greater than Over Temperature
Switch setpoint.
6. Boiler Management System/AERCO Control
System PID or other settings not correctly
setup.
7. No interlock to boiler or BMS/ACS to disable
boiler(s) in event that system pumps have
failed.
8. System flow rate changes are occurring faster
than boilers can respond.
1. Test the temperature switch to insure it trips at its actual water
temperature setting.
2. Check PID settings against Menu Default settings in the Appendix.
If the settings have been changed, record the current readings then
reset them to the default values.
3. Using the resistance charts in the Appendix C, Measure the
resistance of Shell sensor and BTU sensor at a known water
temperature.
4. If unit is in Manual Mode switch to Auto Mode.
5. Check setpoint of unit and setpoint of Temperature Switch; Ensure
that the temperature switch is set higher than the unit’s setpoint.
6. Check the BMS/ACS for changes to PID default values, correct as
necessary.
7. If system pump is controlled by Energy Management System other
than BMS/ACS or pumps are individually controlled by boiler,
check to see if there are flow switches interlocked to the BMS/ACS
or boiler.
8. If the system is a variable flow system, monitor system flow
changes to ensure that the rate of flow change is not faster than
what the boilers can respond to.
HIGH WATER
TEMPERATURE
1. See HIGH WATER TEMPERATURE SWITCH
OPEN.
2. Temp HI Limit setting is too low.
1. See HIGH WATER TEMPERATURE SWITCH OPEN.
2. Check Temp HI Limit setting.
IGN BOARD
COMM FAULT
1. Communication fault has occurred between
the PMC board and Ignition/Stepper (IGST)
board
1. Press CLEAR button and restart unit. If fault persists, contact
qualified Service Personnel.