Before choosing a guide
Identify your water heater from the outside.
The brand is a starting point. The full model, energy source, and control type determine which manual and diagnostic guide apply.
If there is gas odor, a CO alarm, active flooding, or water near electrical equipment, use the emergency checklist first. Do not enter an unsafe space to photograph a label.
Copy these details from the rating plate
- Manufacturer and full model number, including suffixes.
- Serial number, for the manufacturer or service company.
- Fuel and rated voltage, if shown.
- Rated storage capacity or heating input.
- Separate control or display model, if visible without removing a cover.
Do not guess the age or control generation from the jacket color. Keep serial numbers out of public posts; give them directly to the service provider.
Choose the equipment that matches
| System | Exterior clues | Next step |
|---|---|---|
| Gas storage | A storage tank with a gas connection and combustion venting, identified as gas on its label. | Gas tank guides |
| Electric storage | A storage tank with an electrical rating; service covers remain closed. | Electric tank guides |
| Tankless | A compact appliance with a model label identifying on-demand operation. It can be gas or electric. | Tankless guides |
| Heat pump | A tank with a fan/heat-pump assembly or separate heat-pump equipment; confirm the label. | Heat-pump guides |
| Indirect | A hot-water tank served by a boiler circuit; the boiler and tank have separate model details. | Indirect guides |
| RV | Read the water-heater manufacturer's label, not just the coach badge. Some units have both propane and electric modes. | RV guides |
Find the matching instructions
Use the manufacturer's official manual lookup and check that the document names your model. Start with A. O. Smith, Rheem, Bradford White, Rinnai, or Navien. Other brand guides include further manual/support links where available.