Inspect before flushing
We confirm valve serviceability, leakage, error history, water quality, and whether the unit can be safely isolated.
Done Right Since 1950 ✦
Tankless Flushing & Descaling
Tankless flushing circulates an appropriate cleaning solution through the heat exchanger to reduce mineral scale. The service should also include inspection of inlet screens, isolation valves, condensate components, venting, leaks, error history, and overall condition because flushing alone does not correct mechanical or installation defects.
Warning Signs & Reasons to Schedule Service
- Reduced hot-water flow or slower temperature response.
- Scale-related error codes or overheating symptoms.
- No documented maintenance in hard-water conditions.
- Rumbling, whistling, or unusual heat-exchanger noise.
- Visible debris in inlet filters or isolation valves.
What the Process Usually Includes
Isolate and circulate
Water is shut off to the unit and cleaning solution is circulated through the heat exchanger using service ports.
Rinse and clean
The system is flushed with clean water and accessible inlet screens or strainers are cleaned.
Restart and test
Valves are returned to operating position, leaks are checked, and temperature and flow are verified.
Advice for Common Situations
Do not use an arbitrary chemical
Use a manufacturer-compatible descaling product and follow applicable instructions.
A flush is not a repair for everything
Failed sensors, pumps, valves, controls, burners, and installation deficiencies require separate diagnosis.
Set the interval from conditions
Water hardness, usage, temperature, filtration, and manufacturer guidance affect frequency.
Confirm isolation valves exist
Missing or failed service valves can increase the scope of maintenance.
Tankless Flushing & Descaling FAQs
How often should a tankless heater be flushed?
The interval depends on water hardness, usage, treatment, temperature, and manufacturer guidance; annual service is common in harder water but is not universal.
Can I flush a tankless heater myself?
Some owners do, but incorrect valve operation, chemicals, rinsing, or restart procedures can cause damage or leave the unit unsafe.
Will descaling improve flow?
It may when scale is restricting the heat exchanger, but fixture restrictions or other system conditions can also reduce flow.
What if the service valves are stuck?
They should not be forced. Valve repair or replacement may be needed before safe flushing.