AERCO KC Series Equipped with C-More version 3.04 - Manual (Page 69)

TROUBLESHOOTING
7-2
KC1000 WATER HEATER TROUBLESHOOTING TABLE
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 airflow
switch
4. Defective airflow
switch
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 duct
work leading up to the combustion blower for signs of
blockage.
3. Remove the airflow switch and inspect for signs of blockage,
clean or replace as necessary.
4. Measure the airflow 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 switch.
AIRFLOW FAULT
DURING PURGE
1. Blower not running
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.
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.
AIRFLOW FAULT
DURING RUN
1. Blower stopped
running due to
thermal or current
overload
2. Blocked Blower inlet
or inlet ductwork
3. Blocked airflow
switch
4. Defective airflow
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 airflow switch and inspect for signs of blockage,
clean or replace as necessary.
4. Measure the airflow 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.
5. Run unit to full fire. If the unit rumbles or runs rough, perform
combustion calibration.