Giant
Giant Water Heaters Error Codes
Complete list of fault codes and troubleshooting guides. Use the search below to find your specific error.
Advertisements
E0
Control board powers up but displays E0 and will not start heating cycle
Control Initialization Fault
E1
Water heater displays E1 and burner or elements do not turn on
Inlet Temperature Sensor Fault
E2
Display shows E2 and unit shuts down shortly after starting
Outlet Temperature Sensor Fault
E3
E3 error and burner or elements cycle erratically, water temperature unstable
Tank Temperature Sensor / ECO Fault
E4
E4 displayed and burner will not ignite on gas Giant water heater
Flame Sensor / Flame Detection Fault
E5
E5 error and no ignition, repeated clicking from igniter on gas model
Ignition Failure / Igniter Fault
E6
E6 displayed, burner shuts down shortly after ignition
Flame Loss / Unstable Combustion
E7
E7 error and blower fan does not start on power‑vent Giant water heater
Inducer/Blower Motor Fault
E8
E8 displayed, unit locks out and will not restart until power is cycled
High Limit / Overheat Lockout
E9
E9 error and no hot water, control indicates dry‑fire or low water condition
Dry‑Fire / Low Water Detection Fault
F1
F1 fault code on display, water heater unresponsive to temperature adjustments
User Interface / Keypad Fault
F2
F2 code and water temperature overshoots setpoint significantly
Temperature Overshoot / Thermostat Calibration Fault
F3
F3 displayed, fan runs but no ignition on power‑vent gas model
Pressure Switch / Air Proving Fault
F4
F4 code, burner lights then shuts off within a few seconds
Flame Proving Timeout
F5
F5 error and no hot water on electric Giant water heater with digital control
Upper Heating Element Circuit Fault
F6
F6 error and limited hot water on electric Giant water heater
Lower Heating Element Circuit Fault
F7
F7 code, fan runs continuously even when no hot water is demanded
Stuck Relay / Fan Control Fault
F8
F8 error and control indicates sensor mismatch or configuration error
Sensor Configuration / Type Mismatch
F9
F9 code, unit reports communication error between display and main control
Communication Bus Fault
Symptom
Condensation or water pooling on top of or around the base of the water heater shortly after installation
Normal Condensation / Cold Start Moisture
Symptom
Hot water pressure is significantly lower than cold water pressure
Hot Outlet Restriction
Symptom
No hot water at all, gas Giant water heater – pilot will not light or stay lit (standing pilot models)
Pilot Ignition / Thermocouple Failure
Symptom
No hot water, electric Giant water heater – tank full but water remains cold
Total Power Loss / Dual Element Non‑Operation
Symptom
Water heater burner backfires or makes a loud boom at ignition
Delayed Ignition
Symptom
Water heater causes noticeable flickering lights or voltage dips when elements cycle
High Inrush Current / Shared Circuit Issues
Symptom
Water heater cycles on and off frequently with small temperature swings
Short Cycling / Poor Hysteresis
Symptom
Water heater does not respond to thermostat adjustments, temperature remains constant
Thermostat / Control Non‑Responsiveness
Symptom
Water heater emits rotten egg or sulfur smell from hot water taps
Bacterial Contamination / Anode Reaction
Symptom
Water heater fan runs but there is no ignition and no error code displayed
Ignition Sequence Interruption
Symptom
Water heater leaking from the bottom or around the base
Tank Rupture / Drain Valve Leak
Symptom
Water heater leaking from the top around piping connections
Top Fitting / Nipple Leak
Symptom
Water heater makes high‑pitched whistling or hissing noise from piping
Flow Restriction / Partially Closed Valve
Symptom
Water heater making rumbling, popping, or banging noises during heating
Sediment Boiling / Scale Buildup
Symptom
Water heater produces discolored (rusty or brown) hot water
Corrosion / Anode Depletion
Symptom
Water heater T&P (temperature and pressure) relief valve drips or discharges water periodically
Excessive Pressure / Thermal Expansion
Symptom
Water heater trips the electrical breaker intermittently
Electrical Overload / Short Circuit
Symptom
Water heater vibrates or rattles during burner or fan operation
Combustion Fan / Burner Vibration
Symptom
Water is warm but not hot enough, runs out quickly on electric Giant water heater
Single Element Operation / Thermostat Miswiring
Symptom
Water too hot, scalding at taps on Giant water heater without obvious error code
Thermostat Stuck Closed / Overheating
| Error Code | Symptom | Fault Type | Guide |
|---|---|---|---|
| E0 |
Control board powers up but displays E0 and will not start heating cycle
|
Control Initialization Fault | View Details |
| E1 |
Water heater displays E1 and burner or elements do not turn on
|
Inlet Temperature Sensor Fault | View Details |
| E2 |
Display shows E2 and unit shuts down shortly after starting
|
Outlet Temperature Sensor Fault | View Details |
| E3 |
E3 error and burner or elements cycle erratically, water temperature unstable
|
Tank Temperature Sensor / ECO Fault | View Details |
| E4 |
E4 displayed and burner will not ignite on gas Giant water heater
|
Flame Sensor / Flame Detection Fault | View Details |
| E5 |
E5 error and no ignition, repeated clicking from igniter on gas model
|
Ignition Failure / Igniter Fault | View Details |
| E6 |
E6 displayed, burner shuts down shortly after ignition
|
Flame Loss / Unstable Combustion | View Details |
| E7 |
E7 error and blower fan does not start on power‑vent Giant water heater
|
Inducer/Blower Motor Fault | View Details |
| E8 |
E8 displayed, unit locks out and will not restart until power is cycled
|
High Limit / Overheat Lockout | View Details |
| E9 |
E9 error and no hot water, control indicates dry‑fire or low water condition
|
Dry‑Fire / Low Water Detection Fault | View Details |
| F1 |
F1 fault code on display, water heater unresponsive to temperature adjustments
|
User Interface / Keypad Fault | View Details |
| F2 |
F2 code and water temperature overshoots setpoint significantly
|
Temperature Overshoot / Thermostat Calibration Fault | View Details |
| F3 |
F3 displayed, fan runs but no ignition on power‑vent gas model
|
Pressure Switch / Air Proving Fault | View Details |
| F4 |
F4 code, burner lights then shuts off within a few seconds
|
Flame Proving Timeout | View Details |
| F5 |
F5 error and no hot water on electric Giant water heater with digital control
|
Upper Heating Element Circuit Fault | View Details |
| F6 |
F6 error and limited hot water on electric Giant water heater
|
Lower Heating Element Circuit Fault | View Details |
| F7 |
F7 code, fan runs continuously even when no hot water is demanded
|
Stuck Relay / Fan Control Fault | View Details |
| F8 |
F8 error and control indicates sensor mismatch or configuration error
|
Sensor Configuration / Type Mismatch | View Details |
| F9 |
F9 code, unit reports communication error between display and main control
|
Communication Bus Fault | View Details |
| – |
Condensation or water pooling on top of or around the base of the water heater shortly after installation
|
Normal Condensation / Cold Start Moisture | View Details |
| – |
Hot water pressure is significantly lower than cold water pressure
|
Hot Outlet Restriction | View Details |
| – |
No hot water at all, gas Giant water heater – pilot will not light or stay lit (standing pilot models)
|
Pilot Ignition / Thermocouple Failure | View Details |
| – |
No hot water, electric Giant water heater – tank full but water remains cold
|
Total Power Loss / Dual Element Non‑Operation | View Details |
| – |
Water heater burner backfires or makes a loud boom at ignition
|
Delayed Ignition | View Details |
| – |
Water heater causes noticeable flickering lights or voltage dips when elements cycle
|
High Inrush Current / Shared Circuit Issues | View Details |
| – |
Water heater cycles on and off frequently with small temperature swings
|
Short Cycling / Poor Hysteresis | View Details |
| – |
Water heater does not respond to thermostat adjustments, temperature remains constant
|
Thermostat / Control Non‑Responsiveness | View Details |
| – |
Water heater emits rotten egg or sulfur smell from hot water taps
|
Bacterial Contamination / Anode Reaction | View Details |
| – |
Water heater fan runs but there is no ignition and no error code displayed
|
Ignition Sequence Interruption | View Details |
| – |
Water heater leaking from the bottom or around the base
|
Tank Rupture / Drain Valve Leak | View Details |
| – |
Water heater leaking from the top around piping connections
|
Top Fitting / Nipple Leak | View Details |
| – |
Water heater makes high‑pitched whistling or hissing noise from piping
|
Flow Restriction / Partially Closed Valve | View Details |
| – |
Water heater making rumbling, popping, or banging noises during heating
|
Sediment Boiling / Scale Buildup | View Details |
| – |
Water heater produces discolored (rusty or brown) hot water
|
Corrosion / Anode Depletion | View Details |
| – |
Water heater T&P (temperature and pressure) relief valve drips or discharges water periodically
|
Excessive Pressure / Thermal Expansion | View Details |
| – |
Water heater trips the electrical breaker intermittently
|
Electrical Overload / Short Circuit | View Details |
| – |
Water heater vibrates or rattles during burner or fan operation
|
Combustion Fan / Burner Vibration | View Details |
| – |
Water is warm but not hot enough, runs out quickly on electric Giant water heater
|
Single Element Operation / Thermostat Miswiring | View Details |
| – |
Water too hot, scalding at taps on Giant water heater without obvious error code
|
Thermostat Stuck Closed / Overheating | View Details |
No matching codes found
Advertisements