Navien Tankless Water Heater Increase Temperature Over 120 Degrees
Ever turn on the dishwasher and wonder if the water is really hot enough to sanitize your dishes? Or maybe you have a long pipe run to your master bathroom, and by the time the hot water arrives, it’s just… lukewarm. You know your high-tech Navien tankless water heater is a powerhouse, but it seems stubbornly stuck at 120°F.
You’re not alone in this. It’s a common point of confusion for many homeowners. That 120°F limit isn’t a flaw; it’s a critical safety feature. But what if you have a specific need for hotter water?
Here’s our promise to you: This guide will give you the expert, technician-level knowledge to safely and correctly perform a Navien tankless water heater increase temperature over 120 degrees adjustment. We’ll walk you through the why, the how, and—most importantly—the crucial safety precautions you must take.
We’ll cover the factory safety settings, provide a step-by-step walkthrough for making the change, discuss the benefits and risks, and share some pro-level best practices for managing higher water temperatures in your home. Let’s get you the hot water performance you need, the right way.
Why Is Your Navien Water Heater Capped at 120°F? Understanding the Default
Before we touch a single button or switch, it’s essential to understand why that 120°F limit exists. Navien, like all reputable manufacturers, sets this as the default maximum temperature right out of the box. This isn’t an arbitrary number; it’s based on national safety standards to prevent accidental scalding.
The Critical Role of Anti-Scald Protection
Water at 140°F (60°C) can cause a third-degree burn on adult skin in as little as five seconds. For a child, that time is even shorter. The 120°F (49°C) setting provides a crucial buffer, giving you or a family member time to react and move away from water that is too hot, significantly reducing the risk of serious injury.
This setting balances safety with performance, providing water that is hot enough for most daily tasks like showering and handwashing without posing an immediate danger. It’s the responsible starting point for any home plumbing system.
Energy Efficiency and System Longevity
There’s another reason for the 120°F default: efficiency. Every degree you raise the temperature requires your tankless heater to burn more fuel and work harder. Keeping the temperature at a moderate level is a cornerstone of an eco-friendly Navien tankless water heater increase temperature over 120 degrees strategy, as it conserves energy and lowers your utility bills.
Furthermore, hotter water accelerates mineral precipitation—the process that creates limescale. Sticking to 120°F can help extend the time between necessary maintenance cycles, like descaling, which is a key part of any good Navien tankless water heater increase temperature over 120 degrees care guide.
Before You Begin: A Crucial Safety Checklist
Okay, you’ve weighed the reasons and decided you still need to raise the temperature. As an HVACR technician, my first priority is always safety. Please, do not skip this section. Taking a few moments to prepare can prevent accidents and ensure your system runs correctly for years to come.
Understand the Scalding Risk
Let’s be perfectly clear: increasing your water temperature directly increases the risk of scalding. It is absolutely critical that every member of your household is aware of this change, especially if you have young children, elderly individuals, or anyone with sensitive skin living in your home.
Pro Tip: A simple and effective safety measure is to test the water temperature at the faucet furthest from the heater after making an adjustment. Use a reliable thermometer to see what the actual delivery temperature is.
The Pro-Level Solution: Install a Thermostatic Mixing Valve
If you want the best of both worlds—high temperature for sanitation and safe temperatures at the tap—the ultimate solution is a thermostatic mixing valve (TMV). This device is installed in your plumbing after the water heater. It allows you to set your Navien to 140°F (great for killing bacteria and for appliances) but automatically mixes in cold water to deliver a safe, consistent 120°F (or your desired temperature) to all your showers and sinks. This is the gold standard for both safety and performance.
Check Your Local Plumbing Codes
Some municipalities have regulations that cap residential hot water temperatures. Before making any changes, it’s a wise idea to do a quick search or call your local building authority to ensure you remain in compliance. A professional plumber will be aware of these codes.
How to Navien Tankless Water Heater Increase Temperature Over 120 Degrees: A Step-by-Step Guide
Ready to proceed? This section provides the detailed steps for the adjustment. This process involves opening the unit’s front cover to access an internal control board. If you are not comfortable with this, stop now and call a qualified technician. Your safety is more important than any DIY project.
SAFETY WARNING: You will be working near electrical and gas components. You MUST disconnect all electrical power and shut off the gas supply to the unit before opening the cover. Failure to do so can result in serious injury or death.
Step 1: Power Down the Unit
First, turn off the power to the water heater. Unplug the unit from the wall outlet. If it’s hardwired, go to your home’s main electrical panel and flip the circuit breaker that controls the water heater to the “OFF” position.
Step 2: Shut Off the Gas Supply
Locate the manual gas shut-off valve on the gas pipe leading to your Navien heater. It usually has a red or yellow handle. Turn the handle a quarter-turn so it is perpendicular (at a 90-degree angle) to the pipe. This stops the flow of gas.
Step 3: Remove the Front Cover
Using a Phillips head screwdriver, carefully remove the screws holding the front metal cover of your Navien unit. There are typically a few along the bottom and sides. Set the cover and screws aside in a safe place.
Step 4: Locate the Internal DIP Switches
With the cover off, you will see the internal components. Look for the main printed circuit board (PCB). On this board, there is a small bank of tiny switches, often colored blue or red, called DIP switches. Their exact location can vary by model, so this is where your user manual is invaluable. If you’ve misplaced it, you can find digital copies on the Navien website.
Step 5: Adjust the Temperature Lock DIP Switch
The DIP switches control various functions. You are looking for the specific switch that governs the maximum temperature setting. On many popular Navien NPE series models, you need to turn DIP switch #2 in the first bank (SW1) to the ON position. This disables the 120°F lock and enables the higher temperature range, up to 140°F.
Again, always confirm the correct switch for your specific model in your manual before making a change.
Step 6: Reassemble and Restore Power & Gas
Carefully place the front cover back on the unit and secure it with the screws. Turn the gas valve handle back so it is parallel with the pipe. Finally, plug the unit back in or flip the circuit breaker on. Your unit will go through a startup sequence.
Step 7: Set Your New Temperature on the Front Panel
Once the unit is powered on, use the up and down arrow buttons on the front control panel to set your desired temperature. You should now be able to go past 120°F. We recommend starting with a small increase, such as to 125°F, to see if it meets your needs before going higher.
Benefits and Drawbacks of Higher Water Temperatures
Making this adjustment is a trade-off. It’s important to understand both sides of the coin. This is one of the most important navien tankless water heater increase temperature over 120 degrees tips we can offer: know what you’re gaining and what you’re risking.
Potential Benefits of Increasing Temperature
- Improved Sanitation: Some modern dishwashers don’t have their own heating elements and rely on your home’s hot water. Water above 130°F is more effective at killing germs and cleaning greasy dishes.
- Longer “Effective” Showers: Because you’ll be mixing in more cold water at the tap, your Navien won’t have to produce as high of a flow rate of hot water, which can sometimes help if you’re pushing the limits of the unit’s capacity with multiple simultaneous uses.
- Compensating for Heat Loss: For homes with long, uninsulated pipe runs, increasing the temperature at the heater ensures the water is still hot when it reaches the faucet.
Common Problems and Risks to Consider
- The Scald Risk: We can’t say it enough. This is the number one concern and requires constant awareness.
- Accelerated Scaling: This is one of the most significant common problems with navien tankless water heater increase temperature over 120 degrees. Hard water minerals (calcium and magnesium) fall out of suspension and build up on the heat exchanger much faster at higher temperatures. This reduces efficiency and can lead to damage if not addressed.
- Higher Energy Bills: Maintaining a higher temperature means your unit fires more often and for longer. This directly translates to higher gas or electric bills, working against a sustainable navien tankless water heater increase temperature over 120 degrees goal.
- Increased Wear and Tear: Running the unit at its maximum capacity can put additional stress on its components over time.
Best Practices for Managing Water Temperatures Over 120°F
If you’re operating your Navien at a higher temperature, you need to adopt a more proactive maintenance mindset. Following these navien tankless water heater increase temperature over 120 degrees best practices will protect your family and your investment.
Commit to More Frequent Descaling
If you live in an area with hard water, you should be descaling (also called flushing) your tankless unit every 12-18 months. If you increase your temperature to 130°F or 140°F, you should shorten that interval to every 6-12 months. This is non-negotiable for the long-term health of your heater.
Educate Everyone in the Home
Make sure all family members and even guests are aware that the hot water is set to a higher temperature. A small sign near a sink can be a helpful reminder for visitors.
Start Low, Go Slow
Don’t immediately jump to the maximum setting of 140°F. Try 125°F for a week. Is it better? If not, try 130°F. Find the lowest possible temperature that meets your specific need. This incremental approach balances performance with safety and efficiency.
Frequently Asked Questions About Navien Temperature Adjustments
Can I increase the temperature on my Navien without using the dip switches?
No. For nearly all Navien residential models, the front panel controls are electronically locked at a maximum of 120°F for safety. The internal DIP switch is the only manufacturer-designed method to override this safety lock and access the higher temperature range.
What is the maximum temperature I can set my Navien to?
Once the DIP switch is adjusted, most Navien residential models, like the NPE-2 series, can be set to a maximum of 140°F (60°C). Commercial models can go higher. Always check your specific model’s technical specifications in the manual to be certain.
My Navien won’t go above 120°F even after I flipped the dip switch. What’s wrong?
If you’ve correctly followed the steps and the temperature still won’t increase, there could be a few issues. You might have adjusted the wrong DIP switch, the control board may have a fault, or the unit could be in an error state. Double-check your work, and if the problem persists, it is time to call a licensed Navien technician for diagnosis.
Will increasing the temperature void my Navien warranty?
No, simply using the built-in functionality to increase the temperature will not void your warranty. However, damage caused by a lack of maintenance—such as severe scale buildup from running at high temperatures without regular descaling—could potentially lead to a denied warranty claim. Proper care is essential.
Here at HVACRLY, we want you to feel confident and capable when managing your home’s systems. Adjusting your Navien’s temperature is a straightforward task, but one that demands respect for the safety and maintenance protocols involved.
By understanding the risks, following the steps in this navien tankless water heater increase temperature over 120 degrees guide carefully, and committing to proper care, you can unlock the full performance of your advanced water heater.
Stay safe, stay informed, and enjoy that perfectly heated water!
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