AERCO BMK 1.5 LN July 2011 - Manual (Page 84)

PR2: 05/01/11 Page 84 of 152
Benchmark 1.5LN Low NOx Boiler
Operation and Maintenance Manual
OMM-0041_0D
GF-120
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph: 800-526-0288
TABLE 8-1. BOILER TROUBLESHOOTING
FAULT
INDICATION
PROBABLE CAUSES CORRECTIVE ACTION
AIRFLOW FAULT
DURING IGNITION
1. Blower stopped running due to thermal or
current overload
2. Blocked Blower inlet or inlet ductwork
3. Blocked Blower proof switch
4. Blocked blocked-air inlet switch
5. Defective Blower proof switch
6. Defective blocked-air inlet switch
7. Loose temperature to AUX connection in I/O
Box
8. Defective temperature sensor
9. Loose wire connection between the 0-10V
signal from I/O box to the Blower Motor
input.
10. Defective I/O box
11. Wrong 0-10V output selection on the
control box
12. Defective Air-Fuel Valve potentiometer
1. Check combustion blower for signs of excessive heat or high
current drain 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 Blower proof switch and inspect for signs of blockage,
clean or replace as necessary.
4. Remove the blocked-air inlet switch and inspect for signs of
blockage, clean or replace as necessary.
5. Measure the Blower proof 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.
6. Measure the blocked-air inlet 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.
7. Check the actual inlet air temperature and measure voltage at
AUX input in the I/O Box. Verify that the voltage conforms to the
values shown in the tabular listing provided in Appendix C.
8. Refer to CORRECTIVE ACTION 7 and verify that the voltage
conforms to the values shown in Appendix C.
9. Check wire connection from I/O Box 0-10V signal to the Blower
Motor.
10. Measure voltage at the I/O box 0-10V output. A voltage of 8.2V
equates to a 100% open valve position.
11. Check the Analog Out option on the C-More Configuration Menu.
Valve Position 0-10V should be selected.
12. Check Air/Fuel Valve position at 0%, 50% and 100% open
positions. The positions on the VALVE POSITION bargraph
should match the dial readings on the Air/Fuel Valve dial.