AERCO BMK 1.5 LN Dual Fuel Jan 2009 - Manual (Page 59)

TROUBLESHOOTING
TABLE 8-1. BOILER TROUBLESHOOTING – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
(continued) 17. Defective thermal overload contactor.
18. Current overload not set to the proper
current limit.
19. Fuel Selector Switch set to incorrect
position for fuel used or wrong Logic
Stick is installed in VFD.
17. Reset thermal overload contactor.Check position of Fuel
18. Check to ensure that the thermal overload contactor is set to
14 Amps.
19. Check the position of the Fuel Selector Switch and the installed
VFD Logic Stick to ensure the are correct for the fuel being
used.
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 CORRECTIVE 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.
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.
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