How to Repair a Tankless Water Heater [With Proper Guideline]

repair tankless gas water heater

How to Repair a Tankless Water HeaterGot a cranky Tankless water heater that doesn’t heat the water enough or doesn’t heat at all?


is the burner too noisy or doesn’t get ignited?

There is no need to worry as there is a solution to every problem and you might not even have to spend a penny to get the heater working smoothly.

However, trying to repair the heater itself may cause an unforeseen accident, so it is always better to study the manufacturer’s manual before starting with any repairs, as a precautionary measure.

Tankless water heaters come in two variants:

  1. Gas Tankless Water Heater
  2. Electric Tankless Water Heater

Also as the name means, there is no tank to store the water while it gets heated. Instead, the water is continuously running from the main source while it gets heated.

How to Repair a Tankless Water Heater

How to Repair a Tankless Water Heater

Common Solutions

Check the water supply and make sure water is running. Another thing to check is the gas or power supply and see whether the fuel is properly supplied in sufficient amount.

Check the plumbing if the water is not available from the main source and make sure that any material or object does not choke the main pipeline. In case of extreme cold and if any part of the plumbing is outside, the water might have frozen midway in the pipeline.

Tankless water heaters have another characteristic which might prove to be the main factor for its lack of proper operation; the plumbing inside the heater is narrow which allows only a small flow of water so that it can be heated simultaneously.

The problem may persist if hard water is used which contains many salts which clog up the pipeline obstructing the proper flow of water. So it is better to use soft water when it is available.

How to Repair a Gas Tankless Water Heater

Gas Tankless Water Heater mechanismWith a gas water heater, the most common problem is that the burner is clogged, resulting in partial heating of the burner or sometimes there is no flame at all, and the entire burner remains unheated.

Mainly the internal orifices for the water flow are clogged due to the use of hard water. In this case, the internal plumbing must be flushed every few months to maintain the smooth flow of water.

You can get a professional plumber to get the pipes flushed, or you can do it yourself if you have the following devices:

A submersible pump, extra bucket, a couple of hoses, and 2 gallons white vinegar. Now follow the step by step process:

  • Close the water valves for incoming and outgoing pipelines.
  • Shut down the supply of gas so as to avoid an accident.
  • Get a bucket full of vinegar and put the suction pickup of a submersible pump in it. Then get a hose from the bucket to the pressure-relief valve and another one from the submersible pump to the inlet of a tankless water heater.
  • Switch on the pump so that the vinegar will flow through the internal plumbing of the heater dissolving the salts deposited on the walls of the apertures.
  • Then clean the screen filter of the inbuilt filter by removing it from near the water inlet and then screw it back on.
  • Finally, run the pump again but this time to pass some freshwater through the internal piping to clean it one last time before using it again to heat the water.

How to Repair an Electric Tankless Water Heater

Electric Tankless Water HeaterIn case of a tankless water heater that runs on electricity, probably the heating element is faulty and needs to be replaced for which the process is as below:

  • Before doing anything, go through the help manual to find out the location of the heating element.
  • Now switch off the main power to the heater and also shut off the water from its source.
  • Drain out all the remaining water by opening the hot water tap before performing any operation.
  • Take out the plate from the bottom of the heater and after the water’s draining out is finished; replace the heating chamber plate where it was.
  • Now carefully separate the wires attached to the main heating unit and then use a thick cloth to prevent the water from running through the main unit.
  • Unscrew the nut holding the heating element in its position using an adjustable wrench thereby detaching it from the main unit.
  • Get it replaced by an element of the same capacity and also be careful of the O-ring being appropriately set in its position.
  • Now you are ready to go. Turn the water and the power on and check whether the heating is done properly or not.

While it is certainly important to check and perform regular maintenance of the water heater, there is no reason to panic in certain conditions such as the water starting to get heated after some time which is a usual process as it takes some time to get the heat transferred to the water.

Also, the spinning of the fan even after the switch is turned off is normal as the fan is used to shove out the exhaust gasses through the ventilators.

Why do you need a professional to repair your tankless water heater?

Although, you can most certainly fix your tankless water heater if you follow the guide step by step. However, if you aren’t confident about the repair job, we highly advise you to contact a professional.

Tankless water heaters are generally much more complex to repair and maintain as compared to the tank water heater, and the inspection, repair, and maintenance typically do not cost an arm and a leg. Please feel free to contact us whenever you have queries. We are here to help you.