62 • Residen al Gas Water Heater Use and Care Guide
TROUBLESHOOTING
Error
Code
Error Type
Procedure
E417
Flame Sensor Fault
1. Check
the
fl
ame sensor wire for a short or disconnec on. Correct any loose con-
nec ons and replace any damaged wire/connector.
2. Check the inlet & heat exchanger thermistor sensor wires for a short or discon-
nec on. Correct any loose connec ons and replace any damaged wire/connec-
tor.
3. Remove the inlet & heat exchanger thermistors (do not lose the o-ring) and
check for any dirt or debris. Clean with an Emery cloth. If the either thermistor is
damaged, replace it.
E418
Exhaust High Temperature
1. With the water heater power disconnected, check the exhaust vent and air
intake piping for any blockages. Remove any blockages.
2. Remove the exhaust thermistor (do not lose the o-ring) and check for any dirt or
debris clean with Emery cloth. If the thermistor is damaged, replace it.
3. If the error s ll occurs, contact a quali
fi
ed service technician.
E420
Gas Valve - SV2
1. PCB detects an incorrect voltage from the gas valve’s SV2. Correct any loose
connec ons and replace any damaged wire/connector. If the error s ll occurs
contact a quali
fi
ed service technician to replace the gas valve.
E421
Pressure Switch
1. Check the pressure switch wires for a short or disconnec on. Correct any loose
connec ons and replace any damaged wire/connector.
2. Check the pressure tube for loose connec ons, debris, or blockages. Correct any
issue immediately.
3. With the water heater power disconnected, check the exhaust vent and air
intake piping for any blockages. Remove any blockages.
4. If the error s ll occurs, contact a quali
fi
ed service technician.
E422
Venturi Assembly
1. Check the venturi assembly wires for a short or disconnec on. Correct any loose
connec ons and replace any damaged wire/connector.
2. If the error s ll occurs, contact a quali
fi
ed service technician.
E426
Condensate Drain Over
fl
ow
1. Place a bucket under the water heater to catch any water.
2. With the water heater o
ff
, check the condensate drain for any blockages. Remove
any blockages.
3. With the water heater o
ff
, check the condensate trap for any blockages. Remove
any blockages.
4. Check the condensate drain wires for a short or disconnec on. Correct any loose
connec ons and replace any damaged wire/connector.
5. Verify the condensate drain line is installed correctly, reference “Condensate
Drain” on page 39. "
E427
Flow Control Valve
1. Check
the
fl
ow control valve wires for a short or disconnec on. Correct any loose
connec ons and replace any damaged wire/connector.
2. Remove
the
fl
ow control valve and inspect for any debris or damage. Replace if
needed. First follow the draining procedure in the Unit Draining & Power Outage
sec on in this manual.
