AERCO BMK 2.0 LN Natural Gas (SN G-11-1861 and above) - Manual (Page 98)

Chapter 8 Benchmark 2.0LN Low NOx Boiler
GF-123
Troubleshooting Installation, Operation and Maintenance Manual OMM-0046_0E
Page 98 of 170 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 PR1 08/20/12
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FAULT
INDICATION
PROBABLE CAUSES CORRECTIVE ACTION
AIRFLOW FAULT
DURING RUN
1. Blower stopped running due to thermal or
current overload
2. Blocked Blower inlet or inlet ductwork
3. Blocked airflow switch
4. Defective airflow switch
5. Combustion oscillations
6. PROBABLE CAUSES from 3 to 16 for
AIRFLOW FAULT DURING IGNITION applies
for this fault
1. Check combustion blower for signs of excessive heat or high
current draw that may trip thermal or current overload devices.
2. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.
3. Remove the airflow switch and inspect for signs of blockage,
clean or replace as necessary.
4. Measure the airflow switch for continuity with the combustion
blower running. If there is an erratic resistance reading or the
resistance reading is greater than zero ohms, replace the switch.
5. Run unit to full fire. If the unit rumbles or runs rough, perform
combustion calibration.
6. See CORRECTIVE ACTIONS from 3 to 16 for AIRFLOW FAULT
DURING IGNITION.
DELAYED
INTERLOCK OPEN
1. Delayed Interlock Jumper not installed or
removed.
2. Device proving switch hooked to interlocks is
not closed
1. Check for a jumper properly installed across the delayed
interlock terminals in the I/O box.
2. If there are 2 external wires on these terminals, check to see if an
end switch for a device such as a pump, louver, etc. is tied these
interlocks. Ensure that the device and or its end switch are
functional. (jumper may be temporarily installed to test interlock)