To service a tankless water heater, regularly flush the system with descaling solution, check filters, inspect vents, and ensure proper temperature settings for efficiency.
Tankless water heaters deliver endless hot water while saving energy. But without proper maintenance, mineral buildup and wear can reduce efficiency and lifespan. Follow this comprehensive guide to keep your unit running like new for years.
Why Tankless Water Heater Maintenance Matters
Unlike traditional tank heaters, tankless models heat water on demand. This eliminates standby heat loss but exposes components to constant water flow. Hard water minerals like calcium and magnesium accumulate inside heat exchangers, reducing efficiency by up to 25%.
Regular maintenance provides three key benefits:
- Prevents costly breakdowns
- Maintains peak efficiency
- Extends lifespan beyond 20 years
Essential Annual Maintenance Tasks
1. Flushing the System (Descaling)
Descaling removes mineral deposits from the heat exchanger. For most homes, annual flushing suffices. Hard water areas may need biannual service.
What You’ll Need:
| Item | Purpose |
|---|---|
| 5-gallon bucket | Holds cleaning solution |
| Submersible pump | Circulates solution |
| White vinegar or descaling solution | Dissolves minerals |
| Hose kit | Connects to service valves |
Step-by-Step Process:
- Turn off power (breaker for electric, gas valve for gas units)
- Connect hoses to service valves (red=hot, blue=cold)
- Submerge pump in vinegar solution bucket
- Circulate solution for 45-60 minutes
- Flush with clean water for 10 minutes
- Restore power and test operation
For detailed instructions, see our guide on choosing the best descaling pump.
2. Cleaning the Water Filter
Most tankless units have a sediment filter at the water inlet. Clean this every 3-6 months:
- Turn off water supply
- Remove filter housing
- Rinse screen under running water
- Inspect for damage
- Reinstall and check for leaks
3. Checking the Venting System
Proper ventilation prevents dangerous carbon monoxide buildup. Inspect annually:
- Remove any obstructions from vents
- Check for corrosion or damage
- Ensure proper slope (1/4″ per foot upwards)
- Verify secure connections
Advanced Maintenance Considerations
When to Call a Professional
Some tasks require licensed technicians:
- Gas line inspections
- Electrical component testing
- Complex error code diagnostics
- Major component replacements
For replacement parts, we recommend quality components that score high in durability tests.
Water Quality Solutions
Hard water accelerates scaling. Consider these solutions:
- Water softeners (salt-based or salt-free)
- Scale inhibitors
- Whole-house filtration systems
The Water Quality Association provides testing resources to assess your water hardness.
Smart Monitoring
Newer models offer Wi-Fi connectivity for:
- Usage tracking
- Maintenance alerts
- Remote diagnostics
According to Energy.gov, smart water heaters can reduce energy use by 10-15% through optimized operation.
Seasonal Maintenance Tips
Winter Preparation
Prevent freeze damage in cold climates:
- Insulate exposed pipes
- Set freeze protection mode if available
- Consider a recirculation system
Summer Efficiency
Adjust settings for warmer incoming water:
- Lower temperature setting (120°F ideal)
- Check for leaks at connections
- Clean exterior vents of pollen/debris
Troubleshooting Common Issues
| Problem | Possible Cause | Solution |
|---|---|---|
| No hot water | Power failure, gas supply issue | Check breakers/gas valve |
| Fluctuating temperature | Mineral buildup, flow rate changes | Descale, check water pressure |
| Error codes | Various system faults | Consult manual, call technician |
