AERCO BMK 2.0 LN Natural Gas (SN G-11-1861 and above) - Manual (Page 97)

GF-123
Benchmark 2.0LN Low NOx Boiler Chapter 8
OMM-0046_0E I nstallation, Operation and Maintenance Manual Troubleshooting
PR1 08/20/12 AERCO International Inc.● 100 Oritani Dr. ● Blauvelt, NY 10913. ● Ph: 800-526-0288 Page 97 of 170
TABLE 8-1. BOILER TROUBLESHOOTING (Continued)
FAULT
INDICATION
PROBABLE CAUSES CORRECTIVE ACTION
AIRFLOW FAULT
DURING PURGE 1. Blower not running or running too slow
2. Defective Air Flow Switch
3. Blocked Air flow Switch
4. Blocked Blower inlet or inlet ductwork.
5. No voltage to switch from control box.
6. PROBABLE CAUSES from 3 to 12 for
AIRFLOW FAULT DURING IGNITION applies
for this fault
1. Start the unit. If the blower does not run check the blower solid
state relay for input and output voltage. If the relay is okay, check
the blower.
2. Start the unit. If the blower runs, check the airflow switch for
continuity. Replace the switch if there is no continuity.
3. Remove the air flow switch and inspect for signs of blockage,
clean or replace as necessary.
4. Inspect the inlet to the combustion blower including any ductwork
leading up to the combustion blower for signs of blockage.
5. Measure for 24 VAC during start sequence from each side of the
switch to ground. If 24VAC is not present refer to qualified
service personnel.
6. See CORRECTIVE ACTIONS from 3 to 12 for AIRFLOW FAULT
DURING IGNITION.