What are common A. O. Smith water heater problems?
A. O. Smith's instruction manual for its power direct vent gas models lists the faults the gas control watches for. They include poor grounding, reversed polarity in the 120-volt supply, pressure switch faults, an open igniter circuit, ignition failure and an over-temperature cutoff. Most trace back to wiring, venting or the ignition parts.
The manual says many suspected leaks are not leaking tanks, and that the source of the water can often be found and corrected. It also says condensation can appear while the tank refills and should not be confused with a leak.
What do the A. O. Smith LED trouble codes mean?
On the power direct vent models, the LED flashes a number of times that matches the table below, which comes from A. O. Smith's instruction manual 185884-001. Codes differ among A. O. Smith product lines, so use the manual for your model number. The manual says repairs should be done by a qualified service technician.
| LED flashes | Problem | First steps in the manual |
|---|---|---|
| 1 | Inadequate or no earth ground | Check the outlet ground and the water heater's ground connections |
| 2 | Reversed polarity in 120 VAC supply | Check outlet wiring and internal wiring |
| 3 | Pressure switch circuit closed more than 5 seconds after heating starts | Check pressure switch wiring; replace the switch |
| 4 | Pressure switch open more than 5 seconds after the blower starts | Check the sensing tube, vent and intake pipe size and the number of elbows |
| 5 | Open igniter circuit | Check igniter wiring and resistance; replace the igniter or the gas control |
| 6 | Ignition or flame failure after 3 retries; locked out for one hour | Cycle power to reset; check the flame sensor, gas supply and pressure, and igniter |
| 10 | Main burner flame out of sequence | Turn power off 10 to 20 seconds; replace the gas control if it persists |
| 11 | Tank water above 195°F tripped the high-temperature limit | Turn power off and on; replace the gas control if it persists |
| 13 | Water temperature sensor open or shorted | Power cycle; replace the gas control if it persists |
| 14 | Flammable vapor sensor open or shorted | Check sensor wiring and igniter plug; replace the sensor |
How often should an A. O. Smith tank be flushed?
A. O. Smith's manual recommends draining and flushing the tank every 6 months to remove sediment that builds up during operation. The steps: set the blower switch off, shut the manual gas valve, run a hot faucet until the water cools, close the cold inlet, connect a hose to the drain valve, open the drain valve and flush as needed, then close it and refill before restarting.
Both of A. O. Smith's residential warranty sheets say coverage applies only when the tank is free of damaging water sediment or scale deposits. In Sacramento-area wells that report hardness above 200 mg/L, regular flushing is the cheapest way to protect that coverage.
What does the A. O. Smith warranty cover?
A. O. Smith warranties are written by product series, so find your model on the sheet that came with the unit. A residential gas warranty sheet printed in 2004 lists ProMax 6-year models at 6 years on the tank and parts, and ProMax 10-year models at 10 years on the tank and 6 on parts. A 2021 sheet for Voltex heat pump water heaters lists 10 years on tank and parts, with on-site service or labor for the first year only through a factory-authorized service professional.
Both sheets state conditions. Coverage is for the original owner at the original location. If the unit is used for anything other than a single-family home, the 6-year tank warranty drops to 1 year and parts drop to 1 year. The gas sheet requires a new temperature and pressure relief valve piped to a drain and, where the system is closed, a properly sized thermal expansion tank. It says A. O. Smith provides only a replacement heater or part, and that the owner pays labor, shipping and permits.
How much does an A. O. Smith repair cost?
No source gives A. O. Smith-specific prices. National guides put water heater repairs at $150 to $750 with an average of $450 (Fixr, 2025), and $150 to $700 with an average of $455 (HomeGuide). A tank flush runs about $75 to $250 (HomeGuide). A leaking tank body is not repairable, and national guides treat it as a replacement.
How do I check the license of an A. O. Smith repair plumber?
Look up the contractor license number on the CSLB website and confirm the C-36 plumbing classification. Work that needs a permit requires a licensed contractor in California. This site is not affiliated with A. O. Smith. Calls are answered by independent local plumbers who work on A. O. Smith units. Call (916) 712-7030 to talk to a local water heater plumber.
Need a water heater plumber in the Sacramento area?
Call to talk to a local water heater plumber, describe the job and get a quote before any work starts. The call is free.
Frequently asked questions
Why is my A. O. Smith water heater blinking?
How often should I flush my A. O. Smith water heater?
Does the A. O. Smith warranty cover labor?
Sources
- Instruction Manual: Residential Gas Water Heaters, Power Direct Vented models, part 185884-001 (LED troubleshooting, draining and flushing) — A. O. Smith
- Residential Gas Warranty, part 184832-000 (printed 03/04) — A. O. Smith
- Residential Electric Warranty for Voltex heat pump water heaters (September 2021) — A. O. Smith
- Water Heater Repair Cost (updated Aug. 29, 2025) — Fixr
- How much does water heater repair cost? (2025–2026) — HomeGuide
- Check a License — Contractors State License Board (CSLB)
- C-36 - Plumbing Contractor (license classification) — Contractors State License Board (CSLB)
- License Requirement for Minor Work Increases from $500 to $1,000 (CSLB #24-07, Dec. 31, 2024) — Contractors State License Board (CSLB)
- Hardness of Water — U.S. Geological Survey, Water Science School
- 2025 Consumer Confidence Report (North and South Service Areas) — Sacramento Suburban Water District
- 2025 Water Quality Report — City of Folsom