AERCO KC Series Equipped with C-More Controller for Massachusetts Only - Manual (Page 65)

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.