AERCO BMK 1.5 LN Dual Fuel June 2010 - Manual (Page 65)

TROUBLESHOOTING
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 17
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 CORR ECTIVE ACTION from 3 to 17 for AIRFLOW
FAULT DURING IGNITION
AIRFLOW FAULT
DURING RUN
1. Blower stopped running due to thermal
or current overload
2. Blocked Blower inlet or inlet ductwork
3. Blocked air flow switch.
4. Defective air flow switch.
5. Combustion oscillations.
6. PROBABLE CAUSES from 3 to 12 for
AIRFLOW FAULT DURING IGNITION
apply for this fault
7. Unit set for propane operation, but Max
Valve Position was not changed to 70%.
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 air flow switch and inspect for signs of blockage,
clean or replace as necessary.
4. Measure the resistance of the switch for continuity with the
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 f the unit rumbles or runs rough, perform the
combustion calibration procedures in Chapter 4.
6. PROBABLE CAUSES from 3 to 12 for AIRFLOW FAULT
DURING IGNITION apply for this fault.
7. Check Max Valve Position setting in Configuration Menu.
8-3