AERCO KC Series Equipped with C-More version 3.04 - Manual (Page 74)

TROUBLESHOOTING
7-7
KC1000 WATER HEATER TROUBLESHOOTING TABLE – Continued
FAULT INDICATION PROBABLE CAUSES CORRECTIVE ACTION
LINE VOLTAGE
OUT OF PHASE
1. Line and Neutral
switched in AC Power
Box.
2. Incorrect power supply
transformer wiring.
1. Check hot and neutral in AC Power Box to
ensure they are not reversed
2. Check transformer wiring, in AC Power Box,
against the power box transformer wiring
diagram to ensure it is wired correctly
LOW GAS
PRESSURE
1. Incorrect supply gas
pressure.
2. Defective or incorrectly
sized Gas Supply
Regulator.
3. Defective Low Pressure
Gas Switch
1. Measure gas pressure upstream of the
supply gas regulator with the unit firing
ensure it is 14” WC or greater.
2. Measure gas pressure downstream of the
supply regulator with unit firing and adjust the
gas supply regulator to increase the outlet
gas pressure; if outlet gas pressure cannot
be increased, check the sizing of the Supply
regulator.
3. Measure gas pressure at the low gas
pressure switch, if it is greater than 5” WC
measure continuity across the switch and
replace if necessary.
LOW WATER
LEVEL
1. Insufficient water level in
system
2. Defective water level
circuitry.
3. Defective water level
probe.
1. Check system for sufficient water level.
2. Test water level circuitry using the Control
Box front panel LOW WATER TEST and
RESET buttons. Replace water level circuitry
if it does not respond.
3. Check continuity of probe end to the shell,
change probe if there is no continuity.
MODBUS COMM
FAULT
1. Water Heater not seeing
information from
modbus network
1. Check network connections. If fault persists,
contact qualified Service Personnel.
PRG SWTCH CLOSED
DURING IGNITION
1. A/F Valve rotated open
to purge and did not
rotate to ignition position
2. Defective or shorted
switch.
1. Start the unit. The Air/Fuel Valve should
rotate to the purge (open) position, then back
to ignition position (towards closed) during
the ignition cycle. If the valve does not rotate
back to the ignition position, check the
Air/Fuel Valve calibration. If calibration is
okay, the problem may be in the Air/Fuel
Valve or the Control Box. Refer fault to
qualified service personnel.
2. If the Air/Fuel Valve does rotate to the ignition
position, check the purge switch for continuity
between the N.O. and COM terminals. If the
switch shows continuity when not in contact
with the cam, check to ensure that the switch
is wired correctly (correct wire numbers on
the normally open terminals).