Benchmark 2.0 LN Installation, Operation & Maintenance Manual
CHAPTER 8 – TROUBLESHOOTING GUIDE
Page
98
of
168
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0046_0J
06/18/2015
Phone: 800-526-0288
GF-123
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.