Navien Water Heater Maintenance Guide
Neglecting Navien maintenance can lead to reduced efficiency, frequent breakdowns, and expensive repairs or early replacement. Regular servicing extends lifespan, preserves performance, and lowers energy bills.
At a Glance
- Difficulty: Intermediate
- Time Required: 60–120 minutes (full annual service)
- Frequency: Visual checks monthly, filters/valves quarterly, full descaling annually
- Estimated Cost: DIY: $0–$150 (parts and descaler); Pro: $150–$500 (inspection, cleaning, labor)
Routine Maintenance Schedule
| Task | Frequency | DIY or Pro? |
|---|---|---|
| Visual system inspection (leaks, error codes, display) | Monthly | DIY |
| Clean inlet water filter / strainer | Quarterly | DIY |
| Flush heat exchanger / descaling | Annually | DIY (experienced) / Pro |
| Test pressure relief valve | Annually | DIY |
| Check condensate drain and venting | Annually | DIY / Pro |
| Professional tune-up and safety check | Every 1–3 years | Pro |
Safety Warnings
Always shut off electrical power and gas supply before doing any maintenance. Working on a live system risks shock, fire, or explosion. If you smell gas, see active leaks, or are unsure about any step — evacuate, ventilate, and call your gas company or a licensed technician immediately.
Step-by-Step DIY Guide
Step 1: Power, Gas and Water Shutdown
Shut off the electrical power to the Navien unit at the circuit breaker. Turn off the cold-water supply valve feeding the unit and, if applicable, close the gas supply valve. Confirm the unit is powered down and the water inlet is closed before proceeding.
Step 2: Perform a Visual Inspection
Inspect the unit exterior, connections, and nearby piping for signs of leaks, corrosion, rust, or loose fittings. Check the display for stored error codes and note them. Look for water on the floor, wet insulation, or unusual odors.
Step 3: Clean the Inlet Water Filter / Strainer
Locate the cold-water inlet strainer (usually behind a service cover or access port). Remove the screen, rinse it under clean water to remove sediment, and reinstall. Replace the screen if torn or damaged. This keeps flow steady and prevents debris from entering the heat exchanger.
Step 4: Flush and Descale the Heat Exchanger
Set up a pump and hoses or use the manufacturer-recommended bypass kit to circulate a descaling solution (white vinegar or a commercial descaler) through the heat exchanger. Circulate for the recommended duration (typically 45–90 minutes) until scale is removed, then thoroughly flush with clean water. Follow Navien's service manual for concentration and procedure or hire a pro for heavy scale.
Step 5: Inspect and Clear the Condensate Drain and Trap
Locate the condensate drain and trap and remove any visible debris. Flush with water to confirm free flow. In cold climates, ensure condensate lines are insulated or routed to prevent freezing. Replace cracked or clogged condensate traps.
Step 6: Test the Pressure Relief Valve (PRV)
Place a bucket under the discharge pipe and carefully lift the PRV test lever to ensure it opens and allows water to discharge. Release the lever and ensure it reseals without continuous leaking. If the valve fails to seat or leaks continuously, replace the valve or call a pro.
Step 7: Check Venting, Air Intake, and Error Codes
Inspect intake and exhaust vents for obstructions, animal nests, or corrosion. Confirm sealing and proper slope where required. Power the unit back on and review the control panel for any error codes; consult the Navien code list in the manual to interpret and attempt simple resets. Record persistent codes for the technician if you call one.
When to Call a Pro
- Any time you detect a natural gas smell, active leak, or corrosion on gas fittings
- Repeated or persistent error codes after basic resets and maintenance
- Loss of hot water, significant performance drop, or suspected heat exchanger failure