To drain an AO Smith water heater, turn off the power, connect a hose to the drain valve, open the valve, and allow the water to flow out completely.
Draining your AO Smith water heater is essential for removing sediment buildup and maintaining peak efficiency. This guide provides detailed, step-by-step instructions to safely drain your unit while avoiding common mistakes.
Why Draining Your AO Smith Water Heater Matters
Sediment accumulation reduces heating efficiency by up to 30% according to U.S. Department of Energy studies. Regular flushing:
- Prevents premature tank failure
- Maintains water quality
- Reduces energy costs
- Extends unit lifespan
How Often to Drain
AO Smith recommends annual flushing for most models. Homes with hard water may need quarterly maintenance. Signs you need immediate draining include:
- Popping or rumbling sounds
- Rust-colored water
- Reduced hot water output
Step-by-Step Draining Guide
1. Safety Preparation
Turn off power at the breaker (electric) or gas supply line (gas models). For gas units, set thermostat to “Pilot” mode. Wait 4-6 hours for water to cool below 120°F.
2. Shut Off Water Supply
Locate the cold water inlet valve above the heater. Turn clockwise to close. For whole-house shutoff, use your main water valve.
3. Connect Drain Hose
Attach a standard garden hose to the brass drain valve at the tank base. Ensure tight connection to prevent leaks. Route hose to floor drain or outdoor area.
| Hose Type | Recommended For |
|---|---|
| Standard garden hose | Most residential models |
| Heavy-duty rubber hose | Commercial units or long drains |
4. Open Pressure Relief Valve
Lift the lever on the T&P valve to allow air into the tank. This prevents vacuum lock and ensures complete drainage.
5. Open Drain Valve
Slowly turn the drain valve counterclockwise. Expect initial sediment discharge. For stubborn buildup, use a specialized wrench to avoid valve damage.
6. Complete the Flush
After initial drainage, briefly turn cold water supply back on to stir up remaining sediment. Repeat until water runs clear (typically 2-3 flushes).
7. Restart Your Heater
Close drain valve, remove hose, and refill tank before restoring power. Open hot water faucets to purge air from lines. Wait for full recovery before use.
Pro Tips for Effective Draining
- Morning draining allows full day for tank recovery
- Add vinegar during flush for heavy mineral deposits
- Inspect anode rod during annual maintenance
- Consider installing a magnesium anode rod in hard water areas
When to Call a Professional
Contact an AO Smith certified technician if you encounter:
- Persistent leaks at the drain valve
- No water flow during draining
- Visible tank corrosion
- Unusual noises after refilling
For complex models like the SW6DEL series, professional service ensures proper maintenance without voiding warranties.
