A.O. Smith GPD-40 User Manual (English)

Questions and Answers:

V
vjonesAug 23, 2025
Why A.O. Smith GPD-40 has ignition or flame failure?
- A
  Amber GarrettAug 23, 2025
  If your A.O. Smith Water Heater experiences ignition/flame failure and the gas control valve/thermostat has reached the maximum number of retries, which locks it out for one hour, cycle the power to the water heater off and on to reset. Also, ensure the flame sensor is making good contact with the burner flame, the flame is steady, supply and manifold gas pressures are within the installation manual requirements, and the gas supply is not turned off or has too low pressure. Clean the flame sensor with fine steel wool, and check the igniter assembly plug and socket for good connection. Replace the igniter assembly or gas control valve/thermostat if the plug or socket are worn or damaged. Finally, consider replacing the igniter assembly.
N
Nicholas NunezAug 25, 2025
Why A.O. Smith GPD-40 Water Heater has yellow flame?
- M
  marc79Aug 26, 2025
  If your A.O. Smith Water Heater displays a yellow flame, the issue could be due to dirt in the burner ports. Turn off the heater and gas, and then clean the burner head. Additionally, check the combustion air path and intake venting arrangement for any obstructions, as well as ensuring there is enough dilution air for proper combustion.
Y
yjonesAug 27, 2025
Why A.O. Smith GPD-40 Water Heater has water leaks?
- B
  Bethany JohnsonAug 27, 2025
  If your A.O. Smith Water Heater experiences water leaks, try tightening threaded connections on the hot or cold supply connections, relief valve, drain valve, or thermostat threads, as they may be improperly sealed. Inspect other appliances near the water heater for leakage. Also, check for condensation of flue products.
S
Stacy BlackAug 27, 2025
What to do if A.O. Smith Water Heater flame is out of sequence?
- T
  Tina MitchellAug 27, 2025
  If your A.O. Smith Water Heater's gas control valve/thermostat has sensed the main burner flame out of proper sequence, turn the power off for 10-20 seconds, then on again to clear these error codes. If this error code persists, replace the gas control valve/thermostat.
C
Christina MorganAug 29, 2025
How to reset ECO on A.O. Smith Water Heater?
- L
  Lisa SchmittAug 29, 2025
  If the water temperature in your A.O. Smith Water Heater tank has exceeded 195°F and activated the ECO (energy cut off) high-temperature limit, turn the power off for 10-20 seconds, then on again to clear these error codes. If the error code persists, replace the gas control valve/thermostat.
A
Alice BellAug 30, 2025
Why A.O. Smith GPD-40 Water Heater light goes out quickly?
- J
  jennifer17Aug 30, 2025
  If your A.O. Smith Water Heater's light goes out in 4–5 seconds, test the outlet polarity and correct it if it is reversed.
R
Rachel LewisSep 1, 2025
Why A.O. Smith Water Heater T & P valve is leaking?
- N
  nibarraSep 1, 2025
  If the T & P valve on your A.O. Smith Water Heater is leaking, install a thermal expansion tank to address thermal expansion in a closed water system. Do not plug the T & P valve. Also, check the relief valve for proper operation, and again, do not plug the T & P valve if the valve is improperly seated.
R
richsarahSep 2, 2025
How to fix A.O. Smith Water Heater with no earth ground?
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  moorejulianSep 2, 2025
  If your A.O. Smith Water Heater's gas control valve/thermostat senses inadequate or no earth ground, make sure the wall outlet (power supply) is properly grounded and all ground connections/wires on the water heater are securely connected.
J
Jane McleanSep 5, 2025
How to solve reversed polarity in A.O. Smith GPD-40 Water Heater?
- A
  Adam HartSep 5, 2025
  If your A.O. Smith Water Heater's gas control valve/thermostat has sensed reversed polarity in the 120 VAC power supply, ensure the wall outlet/power supply is properly wired, all internal 120 VAC wiring connections and wiring harness have no reversed wires, and the 120 VAC "hot" wire connects to the on/off switch.
C
cturnerSep 6, 2025
Why A.O. Smith GPD-40 smells vent gas odors?
- D
  Denise SmithSep 6, 2025
  If you notice vent gas odors from your A.O. Smith Water Heater, immediately shut it down and contact a service agency to determine the cause. The issue could be due to a lack of air supply, improperly installed vent piping, downdraft, or poor combustion.

A.O. Smith GPD-40 Specifications

General

Model	GPD-40
Type	Gas
Capacity	40 gallons
Energy Factor	0.62
Warranty	6 years
Recovery Rate	40 gallons per hour
Gas Type	Natural gas
Vent Type	Atmospheric
Fuel Type	Natural gas
BTU	40, 000 BTU