How to Clean a Noritz Tankless Water Heater in 7 Steps

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3/4 Inch IPS Isolator Tankless Water Heater…

• Product Features: 3/4 inch IPS isolation tankless water heater service valve kit includes hot and cold isolation valves(600 WOG) a…
• Widely Use: The 3/4 inch size tankless kit is suitable for most American residential use, including domestic and commercial tankle…
• LEAD FREE Certification: The components are certified lead free. Meets all federal & state standards for lead levels in drinking w…

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Descaling your Noritz tankless water heater is essential for maintaining efficiency and extending its lifespan. Hard water minerals build up over time, reducing heat transfer and increasing energy costs. Follow this detailed guide to properly clean your unit.

Why Descaling Matters

Mineral deposits from hard water accumulate inside the heat exchanger. This buildup:

• Reduces heating efficiency by up to 25%
• Causes overheating and potential damage
• Shortens the heater’s lifespan

Noritz recommends descaling every 1-3 years depending on water hardness. Check your water heater’s expected lifespan to understand maintenance impact.

Tools and Materials Needed

Step-by-Step Descaling Process

1. Prepare the Unit

Turn off power and gas supply. Locate isolation valves – red for hot water, blue for cold. Turn both valves to the perpendicular (off) position.

2. Drain Existing Water

Remove drain caps and place bucket underneath. Open hot water drain valve first, then cold. Let all water drain completely.

3. Set Up Circulation System

Connect pump to cold water drain valve with hose. Attach second hose to hot water drain valve, leading back to bucket. This creates a closed loop.

4. Add Cleaning Solution

Pour 4 gallons of vinegar into bucket, submerging pump. For severe buildup, use a commercial tankless water heater descaler instead.

5. Circulate Solution

Open drain valves and run pump for 60-90 minutes. Replace vinegar after 30 minutes for heavy deposits. The unit may display error code 11 – this is normal.

6. Flush the System

Disconnect pump and flush with 20 gallons of clean water. For condensing models, open the drain opener underneath to remove residual solution.

7. Restart the Unit

Replace all caps, turn valves to on position, restore power and gas. Reset the unit to clear error codes. Check our guide on resetting Noritz water heaters if needed.

Additional Maintenance Tips

Cleaning Internal Components

Every 2-3 years, clean these parts:

• Flame rod (use fine sandpaper)
• Ignition plug
• Fan assembly (brush and compressed air)
• Burner chamber

Water Filter Maintenance

Clean the inlet water filter monthly:

1. Turn off water supply
2. Remove filter with adjustable wrench
3. Rinse under running water
4. Reinstall securely

Preventing Future Buildup

Consider these options to reduce descaling frequency:

• Install a water softener
• Use a Noritz anti-scale treatment device
• Add a whole-house filter
• For outdoor units, read about preventing freeze damage

Proper maintenance keeps your Noritz tankless water heater running efficiently for its full 20-year lifespan. Always consult your owner’s manual for model-specific instructions.

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