Tankless Water Heaters

Tankless water heater repair and maintenance can be daunting if it’s your first time owning a tankless water heater. Pricing for repairs isn’t always transparent and can also have hidden costs. We’ll get you up to speed, though!

For over 15 years, Monkey Wrench Plumbing, Heating, Air & Electric has performed tankless water heater maintenance and repair in Los Angeles and the surrounding area. We know how much common repair and maintenance can cost as well as what factors can bump up prices, and we want to get you up to speed.

By the end of this article, you’ll have a better idea of common repairs and maintenance costs, along with what can drive up final costs. With this knowledge, you’ll be able to get a better idea of whether a tankless water heater is right for you or what to expect the next time you call for service.

Common Tankless Water Heater Maintenance and Repairs

Before jumping straight into repairs, it’s important to touch on maintenance. Maintenance is the best way to save yourself from future hassles and ensure that your tankless water heater stays under warranty. From there, you can take a look at the most common types of repairs, followed by what might raise your final bill.


While it may not be an outright repair, standard maintenance is one of the most common service calls. Without regular maintenance, manufacturers aren’t obligated to cover your water heater. This means that the best way to protect your tankless water heater and your wallet is to stay on top of yearly maintenance.

There are two types of maintenance: internal and external. Internal maintenance involves flushing the system to prevent buildup and keep the system running smoothly. Switching to external maintenance, a technician will clean out the fan motor, new intake valve, exhaust, burner assembly, gas manifold, and flame and ignition rods.

Regular maintenance will prevent future breakdowns and repairs, ultimately saving you money and time in the long run. For this type of standard maintenance with Monkey Wrench Plumbing, Heating, Air & Electric, you’re looking at about $249, assuming there are no major issues. But regular maintenance can’t prevent every issue, with one of the most common issues being dud heat exchangers.

Heat Exchanger Repair

One of the most common repairs and replacements is the heat exchanger. The heat exchanger is where cold water is circulated to reach the temperature set on the tankless water heater, so it’s a pretty big deal when something goes wrong here. A broken heat exchanger can cost quite a bit to replace and varies from manufacturer to manufacturer.

Luckily, most manufacturers will cover the heat exchanger the first time it needs to be repaired if the maintenance is up to par. But you may still have to cover labor costs, which run up to about $695. Moving down the price scale, gas flex lines often pose a problem.

Gas Flex Repair

Another common repair is the gas flex. The gas flex often appears as a smaller yellow line that runs from the tankless water heater to the wall where the main gas line is located. This part is a single-use component, and there are also plenty of instances of the wrong gas flex being used, which means it’ll need replacing.

Fixing a damaged or improperly installed gas flex costs around $300 to $400. While this isn’t the most expensive repair, it can still be a pain to deal with and may even signal the need for larger repairs with the main gas line.

Gas Line Repair

Along with the gas flex, sometimes gas lines can be improperly sized and need to be replaced. Likewise, leaks and other issues pop up from time to time and need to be addressed. This is an important one since you’ll need a steady supply of gas to reap the benefits of your tankless water heater, especially in the colder months.

If your gas line needs to be completely swapped out, you’re looking at anywhere from $1,200 to $2,900 for the whole gas line. While this is easily the most expensive common repair, it is an absolute necessity, considering that your tankless water heater becomes a fancy brick without being fueled.

What Factors Affect Tankless Water Heater Repair Cost?

There are a couple of reasons why repair costs can go up or down. Some of them include no-brainers like labor and materials, but the other is a bit more surprising if you’re unfamiliar with tankless water heaters.

Manufacturer Input

One surprising factor that raises repair costs is the manufacturer that supplies your tankless water heater’s warranty. Manufacturers will often ask for photos of the tankless water heater to ensure that a repair needs to happen and what else needs to be done to properly service the unit.

For instance, if you need your heat exchanger replaced and a photo is sent to the manufacturer by your technician, the manufacturer could point out several other components it would like switched out. Depending on what parts are covered under warranty, this can raise your final bill considerably.


Labor costs can easily rise based on the complexity of the job. For instance, if a one-person job requires a second set of hands, your labor costs will go up. While this isn’t necessarily a surprise, being aware of labor costs and budgeting for them will save you a lot of hassle in the future.


Another factor that causes repair costs to go up is materials. For example, if your gas line needs replacing, the length of the pipe needed can increase the repair cost. It’s pretty simple stuff, but it’s always good to remind folks of the realities of these repairs.

When Tankless Water Heater Repair Turns into Replace

As with any piece of technology, you’ll eventually reach a point where your investment no longer yields results. For tankless water heaters, this line is relatively easy to identify.

If you have a busted heat exchanger that needs to be replaced, but your warranty is expired, then there’s little point in replacing the heat exchanger on your own dime. You’re better off buying a new tankless water heater at this point since a heat exchanger is expensive without warranty coverage, and you’re essentially paying a high price for an older part.

This is where repair turns into a replacement for tankless water heaters. A new water heater may be more expensive upfront than repairing, but investing in an older unit that will need replacing sooner rather than later doesn’t quite make sense.

Up to Speed with Common Tankless Water Heater Repairs

We’ve touched on some common repairs, maintenance costs, factors affecting the cost, and when it’s time to walk away from a repair. Now, you can better understand what costs are associated with tankless water heater repair. Whether you’re a new owner or a prospective one, having a good grasp of what repairs can cost will help you avoid surprises in the future.

After 15 years of repairing tankless water heaters, these are the most common repairs we service. While there’s no way to prevent every issue that might arise, maintenance is key in getting the most out of your tankless water heater.

If you think it’s time for yearly maintenance, give us a call at (424) 622-4228 or book a consultation on our tankless water heater page.

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