Maintenance Needs for a Tankless Water Heater

South End Plumbing, Heating, & Air Expert Tips

Maintenance Needs for a Tankless Water Heater
While a tankless system might be called low maintenance, there are some upkeep needs to a tankless system.

The Maintenance Your Tankless Water Heater Needs

You might be thinking about changing over to a tankless water heater for your home. One important question is, what are the maintenance needs for a tankless water heater? A tankless system needs to be serviced as a part of the routine preventative maintenance heating and cooling systems get. Electric or gas components ought to be inspected. Tank water heaters are less effective due to standby losses, but they do not call for a great deal of maintenance. The good news is tankless water heaters don’t require much maintenance, either.

The On-Demand Water System

Tankless water heaters do not come with a big water tank. Rather, on-demand water heaters heat water directly as it flows in the line. So, when you turn on hot water, you’re basically activating the water heater almost instantly. An on-demand water heater uses heating elements, referred to as heat exchangers.

Tankless Water Heater Upkeep

While a tankless system might be called low maintenance, there are some upkeep needs for a tankless system. Owners must use a water softener, as deposits from hard water can create problems through discoloration, scale buildup, and corrosion (on the system itself and plumbing). If you have hard water with a tank heater system, you’re probably using a softener already.

Hard water is a problem for tank systems since as water passes through the tank, acidity forms build-up that collects in the bottom of the tank. This eventually impacts the efficiency of the heat transfer, which can result in early system failure. The same thing can occur with tankless devices, yet more gradually.

Tankless systems become blocked when accumulation happens. You can reset them without taking care of the problem, but the buildup can cause another problem. In this instance, a flush will remove the accumulation. Tank heaters have no remedy for accumulation.

Tankless water heaters are a good idea for many homes and properties. Before switching, though, consider the flow rate even if the system is said to give unlimited hot water. The gallons per minute of a system might mean you should install more than one water heater. A typical setup is one tankless water heater for showers and bathrooms and another for the kitchen and laundry.

What’s Hard Water?

Hard water means water containing minerals, mostly magnesium and calcium. With tankless water heaters, minerals are likely to build inside the heat exchanger. Over a span of months, minerals can clog water lines, slowing the flow rate. This makes the system work more to deliver warm water.

Proper maintenance of the heat exchanger, basically cleaning it, will keep the performance, energy efficiency, and lifespan fine. Mineral accumulation on the heat exchanger can create irreversible wear. In serious instances, the heat exchanger or the whole unit will need to be replaced. Unfortunately, a lot of companies do not cover this sort of damage under the service warranty.

Maintenance Requirements

We recommend having a tankless water heater professionally serviced. During routine service, a pro will descale the water heater to clean out mineral buildup. A water heater needs to be descaled at least annually. It may need to happen more often if you live in an area with hard water or if you normally keep the water heater’s temperature higher than recommended. You may need to have the water heater serviced every six months.

Regardless of where you live or your water service, the water that runs through the system will have some amount of minerals. In certain parts of the nation, the water is a lot harder, which means it has a higher level of minerals.

If you’ve set the tankless water heater’s temperature too high, you’re more likely to get scale or mineral buildup or deposits. Some chemicals dissolve faster when heat is applied. This means the hotter the water is, the faster minerals will build around the burner. If you’re not sure if your water heater is set too high, examine it with a thermostat to see what temperature it is. If the temperature is more than 120 degrees, it’s higher than recommended and it is likely a good time for a maintenance check.

DIY Upkeep for a Tankless Water Heater

Maintenance Needs for a Tankless Water Heater
If the temperature is more than 120 degrees, it’s higher than recommended.

If you want to do some routine maintenance on your own, first read the manufacturer’s owner’s manual to know the correct maintenance and safety instructions.

To begin, turn off the power to the water heater. Remove the storage tank’s cover. This normally entails unscrewing 3-4 screws.

Ensure you have turned off the water valves to the water heater.

Next off, take off the valve caps on the purge valve shutoffs which are on both the cold and hot water valves. This will release the pressure that has probably built up and is high on the inside of the valves. You need to prevent any high-pressure water from bursting out. It can burn and scald you.

Next, attach hose lines to each valve. The manufacturer should include the hose lines with the tankless water heater.

Now you can open the purge port valves. Turn them perpendicularly to the cold and hot water valves.

Flush the system with three gallons of white vinegar. This should remove all mineral deposits. Drain and flush it again using the manufacturer’s instructions.

After the flush is done, twist and close the purge port valves. Disconnect the hoses. Replace and tighten the caps on the valves back to how they have to be.

Find the filter and remove it. Clean the screen and the casing for the filter by rinsing it. Then return the filter.

In order to safely restart the water heater, read and follow the user’s manual. This DIY task seems easy enough, but if you don’t follow the right maintenance and upkeep steps, you can damage the heating elements. If you don’t have the manual or directions you can contact the company’s consumer support or website.


South End Plumbing specializes in leak repairs and water heater installation, so remember, we are just a click away. We also specialize in tankless water heaters – give us a call! South End Plumbing is one of the only companies that will give you a free estimate. Call us at 704-919-1722 or fill out the form online to schedule a visit.

South End Plumbing, Heating, & Air Expert Tips

We're ready to help with all your needs!

Book Online Book Online