Why does my tankless hot water heater go cold in 2022 – Complete Guide

The most common symptom that people see as a tankless water heater owner is not receiving hot water. It is also usually associated with a tankless water heater not working correctly. However, this does not imply that your tankless water heater unit is defective. It may be a misinterpretation on your behalf. So, we will guide you in finding the root cause of your problem of Why does my tankless hot water heater go cold in 2022 and how you can solve it.

Lets discuss some problems of “Why does my tankless hot water heater go cold”

1.     Exceeding tankless water capacity

You may have been pitched a tankless water heater giving you an endless supply of hot water, but at the time of purchase, the thing that you should look for in a tankless water heater is its GPM, which tells the capacity of the tankless water heater. GPM reflects how many gallons of water per minute can tankless heat up to the temperature you have set on the tankless water heater display screen. You can see this on the label.

If the water drawn from the faucet exceeds the capacity of the tankless unit, it won’t heat the water properly. The amount drawn will push the water to the faucet before the tankless water heater can bring it to the desired temperature. Here, your tankless water is not at fault, and you don’t need to worry. You only need to make sure taps open at a time do not exceed the tankless capacity to enjoy a continuous endless supply of water.

2.     Drawing less than the minimum flow rate

Just like a tankless water heater has a limit of excess water, you can also say tankless also have a minimum limit on the water drawn. This is because every tankless water heater has a flow sensor in the unit. It is located near a cold water inlet. As tankless water heaters are energy-efficient, so they have a flow sensor installed.

This flow sensor senses the water flow coming into the unit and starts the unit when the flow exceeds a certain amount. If the water flow doesn’t exceed this amount, then the unit remains off to save energy. So, the tankless unit also has a lower water flow limit. If the water does not exceed it, you will also not get hot water.

Next time, if you open the tap slightly and don’t get hot water, then don’t worry that your tankless water heater has gone bad.

3.     Dirty water filter

The water you get from the waterlines is not fully clean as it hasn’t been filtered, so there is dirt and pieces of stones mixed in it. As this water passes through the tankless water heater, it is filtered by a water filter installed in the tankless unit. This filter-out the dirt and debris in the water. This way, dirt remains with the filter while the tankless water heater heats up clean water to meet your demand. But with time, filtered dirt can clog the pipes and result in no or less water getting into the tankless unit. This results in you getting cold water instead of hot water.

Ask yourself the question when was it the last time you had the maintenance done and water filters cleaned? Was it in the current year or not? This way, you can easily guess whether this is the cause that may be troubling you.

4.     Heating element cracked

Tankless water heaters work on-demand functionality. This means that they begin heating the water immediately upon opening the faucet. They do this with the heat of heating elements installed in it. So, it must have a heating element in perfect condition for a tankless water heater to heat the water. In case the heating elements are cracked, they must be replaced for the tankless water heater to function perfectly. Heating elements can be purchased separately from the tankless unit and are easily available.

If your cold water problem is not resolved by previously mentioned ways, then you should take a look at the heating elements yourself, or you can have it looked at by a professional plumber. You should always check your heating elements at the time of maintenance to ensure they are in perfect condition and continue to be so.

5.     Scalp deposit on the heating element

It must be known that the water you are receiving from your waterline is not pure. It contains a lot of different minerals like calcium and magnesium etc. That’s why this kind of water is called hard water. Whenever the hard water passes through your tankless water heater, the tankless unit heats the water. Several minerals are deposited on the heating element during this process. This mineral deposit is commonly referred to as the scalp. With time, as the scalp accumulates and forms layers on the heating element, it makes it difficult for the element to heat the water. This results in you getting cold water; that’s why tankless is recommended for at least one flushing a year. By flushing the tankless unit, you can get rid of the scalp accumulating in the unit.

Conclusion

There are various reasons Why does my tankless hot water heater go cold in 2022, but it is up to you to figure out which one is troubling you. Knowing the problem is highly beneficial to you in solving it as not every issue may be the fault of the tankless water heater. In such times, not making a hasty decision or diagnosing it yourself without sufficient knowledge is a wise decision. Often, the issue is minor and easily resolved. But by trying to solve it themselves, people tend to increase the harm and the bill associated with fixing it. So, next time if you face a similar problem, you can go through the following checklist to find the root of your problem.

S. NoProblemCauseSolution
1.Exceeding tankless capacityMultiple taps open at the same time1. Control the number of tap open at a time.
2. Contact a plumber and install a small tank with a tankless unit, which will give you hot water in the duration the tankless water heater heats up.
2.Less than minimum water flowOpening the tap slightly to get waterOpen the tap in moderate or total capacity.
3.Dirty water filterDirt and debris deposit and clogs the pipes1. Clean the filter in your annual or semi-annual maintenance
2. install a secondary filter on the cold water pipeline coming into the tankless
4.Cracked heating elementScalp, sediment, very high temperatureReplace the cracked one with a new one
5.Scalp deposit on the heating elementScalp and sedimentAnnual flushing with undiluted vinegar

Frequently Asked Questions

Why is my tankless water heater not staying hot?

The most common reason for this is that the tankless water heater capacity has been exceeded. This capacity decides how much water you can draw while a tankless water heater keeps providing you with hot water. Exceeding it can result in tankless not being able to meet your demand and hence cold water. Conversely, tankless also have a lower limit due to flow sensors that turn off the unit if water drawn is less than a minimum to protect the heat exchanger from overloading.

Why does my Rinnai tankless water heater go cold?

The Rinnai tankless water heater will be in a rest state when it is not heating the water, and you can feel the tankless water heater is cool to touch. Tankless water heater goes into rest state when no water is drawn from the tap. So there is no need to worry that it has stopped working when the display screen is on, but the tank is cold to touch.

How do you troubleshoot a tankless water heater?

There are a variety of issues you can run into with a tankless water heater owner. Among which not getting hot water is the most frequent one. It is a result of exceeding the capacity of your tankless water heater. You can troubleshoot this by controlling the number of taps open or installing a smaller tank with the tankless water heater unit, which will provide you with hot water while tankless is heating the water.

How do you reset a tankless hot water heater?

You can reset the tankless water heater by pressing the reset button. Usually, this button is a red button present on the tankless water heater display screen, or sometimes you may have to remove the panel to reach inside the tankless unit to find this button. Sometimes the tankless water heater may trip due to the extremely high temperature of the water, so you need to reset it to bring it back to life.


Share post on


BESTHEATERGUIDE.COM is reader-supported. When you buy through links on our site, we may earn an affiliate commission.

How to Wire a Tankless Water Heater in 2022 – Complete Guide Tankless heater info

How to Wire a Tankless Water Heater in 2022 – Complete Guide

How to Wire a Tankless Water Heater in 2022 is a crucial question as...

By Emma Johnson
Tankless heater info

How much propane does a tankless water heater use in 2022 – Complete Guide

Are you confused as to why your tankless water heater keeps consuming huge amounts...

By Emma Johnson
How does a tankless water heater work in 2022-  Complete Guide Tankless heater info

How does a tankless water heater work in 2022- Complete Guide

Although tank water heaters are still the most commonly used machines for heating up...

By Emma Johnson
What is the downside of a tankless water heater in 2022 – Complete Guide Tankless heater info

What is the downside of a tankless water heater in 2022 – Complete Guide

Are you willing to know what is the downside of a tankless water heater?...

By Emma Johnson
who makes the best tankless water heater in 2022 – Complete Guide Tankless heater info

who makes the best tankless water heater in 2022 – Complete Guide

The answer to this question is ambiguous. Because all tankless water heater brands compete...

By Emma Johnson
How to reset tankless water heater in 2022 – Complete Guide Tankless heater info

How to reset tankless water heater in 2022 – Complete Guide

You may have instances where you had a problem and called a plumber. The...

By Emma Johnson
Are electric tankless water heaters efficient in 2022? – Complete Guide Tankless heater info

Are electric tankless water heaters efficient in 2022? – Complete Guide

Whenever do we ask ourselves how can one decide whether an electric tankless water...

By Emma Johnson
Are Tankless Water Heaters Worth the money in 2022 – Complete Guide Tankless heater info

Are Tankless Water Heaters Worth the money in 2022 – Complete Guide

Are the tankless water heaters worth the money in 2022? The answer is yes...

By Emma Johnson

Latest Posts

Best Natural gas tankless water heater in 2022 – Reviews & Buyer Guide Tankless heater reviews

Best Natural gas tankless water heater in 2022 – Reviews & Buyer Guide

No matter what part of the world you live in, one of the main...

By Emma Johnson
Best space heater low energy in 2022 – Reviews & Buyer Guide Tankless Heater Brands

Best space heater low energy in 2022 – Reviews & Buyer Guide

A space heater is a common appliance seen in homes, offices, and workplaces in...

By Emma Johnson
Best space heater for garage in 2022 – Reviews & Buyer Guide Space Heater Reviews

Best space heater for garage in 2022 – Reviews & Buyer Guide

Winter is about to be at your doorstep. Are you ready to fight with...

By Emma Johnson
Best space heaters consumer reports in 2022 – Reviews & Buyer Guide Tankless Heater Brands

Best space heaters consumer reports in 2022 – Reviews & Buyer Guide

After hearing the footsteps of winter, your very next step is to find the...

By Emma Johnson
Best space heater brands in 2022 | Reviews & Buyer Guide Tankless Heater Brands

Best space heater brands in 2022 | Reviews & Buyer Guide

A space heater is a need for today's luxurious homes. Winter is especially incomplete...

By Emma Johnson
Best space heater for basement in 2022 – Reviews & Buyer Guide Space Heater Reviews

Best space heater for basement in 2022 – Reviews & Buyer Guide

The best space heater for basement has an intense cry all around. This is...

By Emma Johnson
Best tankless water heater for Condo in 2022 – Reviews & Buyer Guide Tankless heater reviews

Best tankless water heater for Condo in 2022 – Reviews & Buyer Guide

Traditional water heaters are far more frequent in homes, but tankless water heaters have...

By Emma Johnson
Best Point of use tankless water heater in 2022 – Reviews & Buyer Guide Tankless Heater Brands

Best Point of use tankless water heater in 2022 – Reviews & Buyer Guide

A Point-of-Use tankless water heater is a water heater that is designed to provide...

By Emma Johnson