Why is My Tankless Water Heater Beeping?

Tankless water heaters are frequently described as low-maintenance or requiring little upkeep, but that doesn’t imply they are trouble-free. Several potential problems might develop, just as with any mechanical device. The advantage is that tankless water systems can alert you to issues as they arise.

If there is an issue with the system, your tankless water heater will “beep” and show an error code. Tankless water heaters will sound an audible warning if maintenance is necessary, a part breaks, or a gas or water leak. The error code description may be found online or in the service manual.

If your tankless water heater appears to run out of hot water, it’s probably not a malfunction but rather an increase in demand. Errors are still conceivable in any case.

What a Tankless Water Heater Beeps Means

Each manufacturer uses different error codes, and each set of regulations has a different meaning. However, the sorts of issues that arise are often the same. This article discusses some typical problems with tankless water heaters that you could run across. So let’s get going.

1. There is a Limescale Buildup

Numerous minerals, including calcium and magnesium, are present in the water that enters the tankless water heater. As the water moves through the earth, where certain minerals may be present, it absorbs them.

Depending on where you live, they may or may not be present in your water supply. The levels change depending on the location. You must contact your neighbourhood water provider for the most accurate information for your region.

The US Geological Survey uses the amount of calcium carbonate in the water to assess its hardness. It calculates the amount of calcium carbonate present per litre in milligrams:

Classification mg-CaCO3/L
Soft 0–60
Moderately hard 61–120
Hard 121–180
Very hard >181

If you reside in a region with hard water, limescale buildup will occur in the piping and fittings of your tankless water heater.

Although it will take longer before it becomes an issue, it can also occur when the water is softer.

Your tankless water heater’s performance, economics, and efficiency can all be impacted by limescale buildup.

You must cleanse or descale your system if you face this issue.

2. The system has detected a water leak

According to your tankless water heater error number, there are two potential reasons for a water leak. One is that there is a leak in your plumbing. The other is that the water leak sensor has an issue.

Your tankless water heater might turn off in any case. It protects the unit or your property from being harmed by water leaks.

Water may collect on the floor next to the water heater or inside the casing, sometimes making the leak obvious. The pipes or the heat exchanger might be the source of the leak. Then it’s time to make a plumber appointment.

You must inspect the leak sensor directly if you cannot detect any signs of leaking. Verify that the wiring is intact and hasn’t been damaged.

If the wiring appears in good condition, the sensor may be damp. Dry the sensor and any moisture within the heater casing before resuming the operation.

If it succeeds, the immediate issue has been resolved. However, it would be best to investigate how the moisture initially got on the sensor.

Try unplugging the sensor and restarting the system if you still receive the problem code. Then continue the water heater. If the procedure functions well without the sensor, there’s a good possibility that the sensor has malfunctioned and you need a new one.

3. The Water Flow Rate Is Insufficient

Your tankless water heater has to flow water at the right pace to operate correctly. The minimum flow rate, expressed in gallons per minute, should be stated for each manufacturer’s model.

If the flow rate is less than the minimum recommended for your model, the heater won’t operate. Therefore you won’t receive any hot water.

This is so that your heater will ignite. The system requires a minimum flow rate to open the flow switch. If you’ve ever opened a hot water faucet just a bit, you’ve undoubtedly had this happen. The water will not warm up.

Due to insufficient amounts of incoming cold water passing through the heat exchanger, the unit runs the danger of overheating, which is the issue with low flow. As a result, it turns off to prevent further harm. Additionally, the shutdown stops the water from being overheated and provides a burn danger.

Try completely opening the faucet to see if you receive hot water.

However, there are a few potential causes for this if you completely open the faucet and you still don’t get hot water, and the water flow doesn’t increase.

Grit or particles may have clogged the input filter at the water supply’s incoming source. The flow rate should increase after clearing things away.

Additionally, make sure the aerators on the faucets aren’t blocked. Alternately, it might be that the system has trapped air, in which case you’ll need to bleed it.

The accumulation of limescale, as mentioned above, might also be a factor. Limescale buildup can obstruct pipes and reduce flow rate.

4. You’ve Submitted a System Overload.

The minimum flow rate and flow rate capacity of your tankless water heater are identical, and both indicate how much hot water your household may consume simultaneously.

You will overload your system if you use more power than it can. All appliances’ demand for hot water will exceed the heater’s capacity. While some will receive hot water, others won’t. The system will frequently shut down to avoid harm.

When selecting a tankless water heater, you should determine your anticipated simultaneous hot water needs. In other words, how many water appliances do you intend or anticipate using concurrently? Showers, bathtubs, sinks, and washing machines must all be mentioned.

The only option to increase the hot water supply if the system is overwhelmed but still functioning is to decrease demand. For instance, shut off the faucets.

If the system goes down due to overloading, it could restart after your hot water usage is reduced. You’ll have to perform a manual reset if not. The process should be described in your user handbook.

5. The Air Supply or Exhaust Has a Blockage

An air inlet on your tankless water heater provides air for the combustion process. Additionally, a fan will bring in outside air and an exhaust vent to let waste gases out.

The system will alert you to the problem if the air intake, circulation fan, or exhaust vent is broken or clogged.

This is because the heater won’t be able to heat the water if it can’t suck in any or enough air.

The system may need to shut down for safety reasons if an obstruction in the exhaust vent traps hazardous waste gases.

Therefore, you must repair any broken venting components and unclog any obstructions.

Fan and vent obstructions frequently occur due to an accumulation of dust, insect carcasses, lint, and bird nests.


The following time your tankless water heater beeps, you’ll understand what it’s trying to tell you about its functionality.

As a result, look at the error code on the display. You can determine the type of issue the system is experiencing after you get the error code.

Some typical issues were mentioned in this article. Check your user manual or go to the manufacturer’s website for a more detailed list of problems.