AERCO KC1000 Water Heater July 2011 - Manual (Page 66)

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.