A.O. Smith GPD-40 - User Manual

Questions and Answers

M
Mrs. Alexandria Pierce MDSep 12, 2025
Why A.O. Smith GPD-40 vent pipe is deformed?
- T
  Tara JamesSep 12, 2025
  If you notice the vent pipe of your A.O. Smith Water Heater is deformed or discolored, take the unit out of service immediately and call a service representative due to a potentially defective air flow restrictor. Proper dilution air must be provided for combustion and dilution of flue temperature. If the dilution air is too hot, check for heat sources around the intake terminal and blockage of the dilution air leg. Also, ensure the correct burner orifice is installed.
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?
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  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.
W
Whitney DelgadoNov 21, 2025
Why A.O. Smith GPD-40 Water Heater has not enough hot water?
- W
  Whitney WagnerNov 21, 2025
  If you're not getting enough or any hot water from your A.O. Smith Water Heater, there could be several reasons: * The "ON/OFF" control switch might be turned off. Turn it to the "ON" position. * The blower might be unplugged. Plug it back into the 115 VAC outlet. * There might be no power at the outlet. Get the outlet repaired. * The thermostat might be defective. Replace it. * The control harness could be defective. Replace the control harness. * The high limit control circuit might be open. Replace the ECO. * The blower motor could be defective. Replace the blower assembly. * The thermostat might be set too low. Turn the temperature control higher. * Either the thermostat or ECO could be defective. Replace the thermostat or ECO as required. * The heater might be und...
H
haleysilvaSep 18, 2025
What to do if FV sensor is open or shorted in A.O. Smith GPD-40?
- J
  Jaclyn JohnsonSep 18, 2025
  If your A.O. Smith Water Heater's self-diagnostic check has detected the FV (flammable vapor) sensor is either open or shorted, turn off the power to the water heater. Ensure all FV sensor wiring, the igniter assembly plug, and the igniter assembly socket on the bottom of the Intellivent control are making good contact. Repair or replace any worn/damaged components that are not making good connection. Replace the FV sensor.
S
Stacy SanchezSep 23, 2025
How to remove odors from A.O. Smith GPD-40?
- J
  Jamie HooverSep 23, 2025
  To address hot water odors in your A.O. Smith Water Heater, drain and flush the heater thoroughly, then refill it if the issue is due to high sulfate or mineral content in the water supply. If bacteria in the water supply is the cause, chlorinate the water supply.
A
Ashley RomeroSep 9, 2025
How to fix LDO lockout on A.O. Smith Water Heater?
- K
  Kevin HolderSep 9, 2025
  If the gas control valve/thermostat on your A.O. Smith Water Heater has detected the air pressure switch circuit is opening repeatedly during one heating cycle, resulting in an LDO (Lint, Dust, and Oil) lockout condition, check and clean the dilution air intake screen on the blower assembly if your model has one. Also, check and clean the combustion air intake screen on the base ring (bottom) of the water heater if equipped, ensuring intake air screens are not obstructed.
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.

Summary

SAFE INSTALLATION, USE, AND SERVICE

GENERAL SAFETY

Safety messages and instructions for installation, use, and service of the water heater.

INSTALLATION REQUIREMENTS FOR THE COMMONWEALTH OF MASSACHUSETTS

CARBON MONOXIDE DETECTOR REQUIREMENTS

Specifies mandatory installation of carbon monoxide detectors for safety.

TYPICAL INSTALLATION

MIXING VALVE USAGE

LOCATING THE NEW WATER HEATER

FACTS TO CONSIDER ABOUT THE LOCATION

COMBUSTION AIR AND EXHAUST TERMINATION CLEARANCES

VENTING THROUGH AN OUTSIDE WALL CLEARANCES

VENT TERMINATION CLEARANCES

INSTALLING THE NEW WATER HEATER

WATER PIPING

Instructions and warnings related to connecting the water supply and drainage.

TEMPERATURE-PRESSURE RELIEF VALVE

GAS PIPING

GAS PIPING INSTALLATION

Guidelines for connecting the gas supply, including shut-off valves and sediment traps.

WIRING SCHEMATIC

ELECTRICAL SAFETY AND INSTALLATION

Critical safety warnings and instructions for electrical wiring and power supply.

VENT CONNECTIONS TO BLOWER ASSEMBLY

VENTING THROUGH AN OUTSIDE WALL

VENTING SYSTEM EXAMPLE INSTALLATIONS FOR ALL MODELS

CONNECTING VENT TO BLOWER

MAKING THE JOINT

SAFETY BEFORE LIGHTING

OPERATING INSTRUCTIONS

Step-by-step guide for the initial operation and lighting of the water heater.

TEMPERATURE REGULATION

HOT WATER CAN SCALD

Warnings and advice on preventing scald injuries from hot water.

START UP CONDITIONS

PERIODIC MAINTENANCE

VENTING SYSTEM INSPECTION

ANODE ROD

TEMPERATURE-PRESSURE RELIEF VALVE OPERATION

Instructions on how to manually operate and check the T&P relief valve.

LEAKAGE CHECKPOINTS

TROUBLESHOOTING GUIDELINES

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