It’s easy to see why so many homeowners would opt for a tankless water heater, despite the upfront cost.
These compact, wall-mounted units provide hot water on demand while using 24% to 34% less energy than traditional storage tank setups. That’s a significant cost-saving potential.
But if you have yours freshly installed, you may wonder what you should do to get the most out of your demand-type water heater. After all, if you spent a few thousand bucks on an appliance, you definitely would want it to last.
Here’s everything a homeowner should know about tankless water heater maintenance.
Do Tankless Water Heaters Need Maintenance?
Besides their low operating power, tankless water heaters tend to be more durable than their conventional counterparts. Most systems have a life expectancy of 15 to 20 years, but can last even longer with good maintenance.
A storage-tank water heater generally has a service life of 10 to 15 years.
Despite their durability, like most home equipment, long-term use can lead to issues that may affect an on-demand water heater’s performance.
One common problem homeowners face is mineral buildup.
Hard water contains minerals, primarily magnesium and calcium. And when water interacts with high temperatures, the minerals it carries don’t evaporate. Instead, they “precipitate” and become insoluble.
This insoluble matter sticks and solidifies in the system, particularly in the walls of your heating system’s chamber. We call this process “scaling,” and it can result in various issues.
With too much scale built up, it can restrict your tankless heating unit’s flow and overall efficiency.
Other common issues, besides scaling, that require regular checkups and maintenance to prevent include blocked exhaust vents and ignition failure.
Why Tankless Water Heater Maintenance Is Important
While built to last, neglecting maintenance on your water heater can cause serious problems, resulting in reduced performance and potentially costly repairs.
Regular maintenance and servicing are necessary to keep a tankless water heater unit’s benefits.
The internal heat exchanger, for one, can be especially vulnerable to mineral deposits. Besides the structural risks, too many scales can prevent the system from heating the water sufficiently, causing it to use more energy.
Left alone, the scaling will worsen, increasing your bills and encouraging wear and tear on the internal components.
The mineral sediments don’t just affect the heat exchanger; they can also invade the heater’s inlet water filter, which is the part that stops debris from entering the heat exchanger.
When the filter becomes clogged, the flow paths inside the unit narrow, lowering the water pressure. If you notice weak flow when washing the dishes, you may have a mineral clogging issue in your hands.
However, the most important reason to maintain a tankless water heater is to extend its life, making every dollar in your investment count.
Although infrequent servicing can feel cheaper now, it only means you’ll potentially spend more for repairs in the future.
What Maintenance Is Required For a Tankless Water Heater?
There are several things you need to do and remember to keep your on-demand hot water system working as intended.
Key maintenance tasks include descaling mineral sediments, cleaning and replacing the inlet and air filter, and inspecting the vent system.
How to Maintain a Tankless Water Heater
Descaling or flushing the tankless water heater unit is crucial for optimal performance. This means removing all the minerals that accumulated inside the system.
If you have basic plumbing knowledge and have a submersible pump, you can descale your unit by yourself.
Important note: Do remember that if you damage your unit while doing DIY descaling, you may void your warranty and lose its benefits, or worse, damage and compromise the appliance.
Here’s how to descale a tankless water heater:
- Before doing anything, make sure to turn off the water heater by unplugging the unit from the power source. For gas systems, cut off the gas supply before descaling.
- Next, remove the caps from the service valves. Many designs have two (cold and hot) valves, but some will have three. You can read your user manual to identify these components.
If you can’t find any service valves, consult a professional for servicing to avoid damaging the water heater.
- Securely attach an adequately-sized hose to each valve. In most cases, you’ll need a hose that’s 3⁄4 in (1.9 cm) in diameter. Then, put the other ends of the hoses into a big enough container.
- Turn the service lever upward one at a time. Expect some water to come out of the hoses. If there are T-shaped levers above the valves, open them slowly after draining the water to release the pressure inside.
- Place your submersible pump in the container and secure the hose (cold water) to the discharge outlet. Pour a descaling solution into the container until it submerges 2 to 3 inches of the pump.
After setting up the submersible pump, turn it on and keep it running for about 30 to 60 minutes. When you see the liquid turning cloudy or debris floating around, you’ve successfully descaled your tankless water heater.
Make sure to maintain the solution’s amount when turning on the submersible pump to prevent damaging the motor.
Don’t forget to check the water heater’s manual to find if there’s a specific descaling solution the manufacturer recommends.
Once done, turn your water heater on and let some hot water run for a few minutes to flush out leftover solution from the system.
In addition to descaling, inspect your water heater’s air and inlet filters and replace them if necessary. If the debris is minimal, you can simply clean and put them back.
The condensate trap is another thing you want to look into. It’s usually found under many tankless water heater units and needs replacing every several months.
How Often Should a Tankless Water Heater Be Serviced?
In general, a tankless water heater needs to be cleaned once a month. Keeping the unit’s exterior pristine not only preserves its appearance but also prevents debris from getting into the system.
While cleaning, always check for any signs of wear and tear.
For professional flushing or descaling, we highly recommend doing it once a year. This should keep the entire system working properly and as efficiently as possible.
However, if you live in an area with very hard water, you may need to flush the system twice every year.
The water filter needs to be cleaned every six months to maintain high performance. The same goes for the air filter. Do this more frequently if you’re using hard water.
Pressure relief valve (PRV) testing should be done once a year. This is a crucial safety check as the PRV, also called the T&P, is the device that releases water if the pressure or temperature reaches unsafe levels.
Debris and mineral sediments can hinder the PRV’s function, leading to serious situations that could endanger someone’s life.
Tankless Water Heater Maintenance Cost
Many professionals provide maintenance plans for homeowners with tankless water heaters. These plans usually involve all the necessary yearly inspections, cleanups, and some minor repairs.
Annual maintenance plans can cost anywhere between $100 and $300. These preventative measures can be a smart way to avoid breakdowns and failures at a cost less than a single major repair.
Full system diagnostics can cost you about $100 to $250.
If you’re doing it DIY, you’ll have to invest in a submersible pump, which can cost anywhere from $50 to $200. You’ll need to purchase suitable hoses and a descaling solution, worth roughly $20, depending on the brand.
DIY vs Professional Tankless Water Heater Maintenance
One of the most important water heater maintenance tips we can give is this:
Simple maintenance tasks like cleaning and replacing the water heater’s filters can be done with little to no experience.
However, while DIY descaling can seem attractive to save money, the complex procedure comes with many risks that professionals know to avoid. As such, if you’re a first-time tankless water heater owner, it’s safer to hire a professional.
Tankless water heater systems involve plumbing, electrical, and gas connections. Mishandling any of these can lead to gas leaks, electrical issues, code violations, and accidental damage to the heat exchanger.
Then there’s also the warranty issues. Many manufacturing companies explicitly require regular servicing from a qualified technician as part of the warranty obligations.
That means if you don’t take care of your unit, you may end up paying out of your own pocket for replacements and repairs!
Signs Your Tankless Water Heater Needs Maintenance
There are several signs to watch for if your tankless water heater needs servicing. If you notice the following, it may be time to call a pro for a full checkup:
- Hot water isn’t as cold or doesn’t last as long as it used to
- Unusual noises are coming out of your water heater
- Error codes are constantly showing from your unit
- There is a visible buildup of debris around inlets or outlet fittings
A somewhat indirect way to tell if your water heater is malfunctioning is your energy bill. If there’s a sudden spike in your energy costs, one of your appliances could be causing it.
FAQs
How does a tankless water heater work?
A tankless water heater heats the water as it passes through its system. When you turn the hot water tap, cold water flows through the heat exchanger, which uses gas or electricity.
Do tankless water heaters need to be flushed every year?
Yes, it is recommended to flush or descale tankless water heaters annually. However, homeowners using hard water should increase the frequency to twice a year.
How long does tankless water heater maintenance take?
Tankless water heater maintenance takes about 1 to 2 hours to complete. This includes filter replacements and system flushing.