AERCO BMK 3.0 LN Nat. Gas June 2010 - Manual (Page 60)

APPENDIX B
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 air/fuel 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 position on the VALVE POSITION bar graph should
match the reading on the Air/Fuel Valve dial.
8-2