No, the heat exchanger in a tankless water heater only expels water when hot water is being used, not continuously.
Tankless water heaters are known for their efficiency and endless hot water supply. But homeowners often wonder if their heat exchangers continuously expel water. The short answer is no – properly functioning heat exchangers should not leak or expel water constantly.
How Tankless Water Heater Heat Exchangers Work
The heat exchanger is the core component that transfers heat from the burner to your water supply. Here’s how it functions:
- Cold water enters through the inlet pipe
- Gas burners or electric elements heat the exchanger
- Water absorbs heat as it flows through coiled pipes
- Hot water exits through the outlet pipe
A well-maintained system forms a closed loop with no water loss. The optimal temperature setting helps maintain efficiency without stressing components.
Condensation Drainage
During normal operation:
- Combustion creates some water vapor
- Vapor condenses inside the unit
- Condensate collects in a trap
- Small amounts drain periodically
This is different from continuous water expulsion. About 1-2 cups per day is normal according to manufacturers.
Signs of Heat Exchanger Problems
Watch for these symptoms of a failing heat exchanger:
| Symptom | Possible Cause |
|---|---|
| Constant water dripping | Cracked heat exchanger or faulty seals |
| Rust-colored water | Corrosion inside exchanger |
| Fluctuating temperatures | Mineral buildup restricting flow |
| Unusual noises | Scale accumulation or component failure |
Common Causes of Leaks
Several issues can lead to water expulsion:
- Mineral buildup causing cracks
- Frozen pipes in winter
- Excessive water pressure
- Failed gaskets or seals
- Improper installation
According to Department of Energy guidelines, annual maintenance prevents most of these issues.
Maintenance to Prevent Water Loss
Proper care keeps your heat exchanger sealed:
Annual Flushing
Use white vinegar or descaling solution to remove mineral deposits. This maintains water flow and prevents cracks.
Filter Cleaning
Clean inlet water filters every 3-6 months. Clogged filters strain the system.
Professional Inspection
Have a technician check for:
- Gas pressure levels
- Ventilation integrity
- Burner condition
- Heat exchanger corrosion
The right descaling solution makes maintenance more effective.
When to Call a Professional
Contact a technician if you notice:
- Continuous water flow from the unit
- Error codes on the display
- Sudden drops in water pressure
- Discolored or smelly water
Most manufacturers recommend professional servicing every 2-3 years to maintain warranty coverage.
Replacement Considerations
If your heat exchanger is leaking significantly, replacement may be more cost-effective than repair. Modern units offer better efficiency and cold climate performance.
