Why am I not getting hot water from my tankless water heater? This is frequently asked a question, and every second person faces this issue. Most users complain that their tankless water heater goes cold after a few minutes.
It is one of the common problems most people face while using a water heater. This is called a cold water sandwich, where suddenly a heater releases cold water after hot water.
Or sometimes you face hot water for a minute, then cold water for a minute and then again hot water after some time. This tankless water heater hot then cold is basically due to different defects. cold water sandwich solution is to run multiple faucets or showers at a time.
You may need to call a plumber, but first, try to correct yourself professionally. Here are some reasons why tankless water heater remains cold after some time.
Why Does My Tankless Hot Water Heater Go Cold
Do you ever face hot water going cold quickly? Here are the reasons!
Calcium and Mineral Build-Up
The most common reason tankless water heater goes cold after some time is the calcium and mineral build-up. These minerals come due to external resources when installing a heater near a mineral source or the sea.
On typical days, if your water is hard by adding these minerals, this is one of the biggest reasons for the cold water. And you need to soften the water and water supply. Otherwise, these minerals can lead the serious damage issues to the heater.
Read how a tankless water heater works and make the usage of this appliance easy for you.
Gas Tankless Water Heater is not Maintained Properly
An electric tankless water heater is easier to maintain than a tankless gas heater. However, a gas tankless water heater is sensitive and needs more attention. The reason is the usage of gas and its effects.
When you use a gas tankless water heater at the start, it works fine. But with time, when gas is burned and used, gas particles themselves accumulate in the vent, pipes, exhaust system, and valves.
In the end, the burner becomes damaged, and the gas heater starts releasing cold water after some sudden burning. The impact does not show externally, but internal damages are great. Also, fixing this issue is not easy, and you may need to call a plumber or professional for this purpose. He will fix the issue by replacing the pipe and venting system.
Less Hot Water Flow
Sometimes, there is not enough water flow that is required to run smoothly. This flow is needed to heat the water, and when there is low flow, its means that water will not heat up.
To fix this issue, try to run multiple faucets or showers simultaneously. Keep them turned ON for maximum time and then see if the problem is solved. However, if the problem is still persistent, you need to call a professional plumber.
Dirt Flame Sensor
The dirty flame sensor is another reason for tankless water heater suddenly cold. The flame sensor can turn off automatically when there is not enough flame or when there is less than normal flame. It is located near the burner and is like a rod.
When this rod is dirty, it can no longer detect the hot water supply or the burner activity and shut off the hot water supply. It’s not working, and even you cant analyze the issue. In this case, turn off the heater and clean the sensor.
Low Gas Pressure
Most of the time, the natural gas coming towards your home has very low pressure, which is even less than the normal required for working. This may happen due to gas pipe leakage or bad installation.
In this case, try to increase the gas pressure, and if you are not able, then calling a plumber or professional would be a great choice. Or the third option is replacing your tankless water heater.
Defect in Flow Sensor
The flow sensor is an important part of the tankless water heater on which the whole model is based. It can detect water flow, and hence its function is to ignite the water heater.
Hence, if it’s not working, it would fail to detect water flow, turning off the hot water supply. In return of which, you need to replace it or call a plumber.
These are some basic reasons why does my tankless water heater goes cold and their solution.
Frequently Asked Questions
Why does my Rinnai tankless water heater go cold?
Don’t worry as nothing happens. Normally, your Rinnai tankless water heater does not work when it’s in the resting phase.
Can I insulate a tankless water heater?
You can insulate by using insulation material on pumps and the overall heater.
Wrapping Up- Tankless Water Heater Goes Cold
Hence, a tankless water heater going cold after a few minutes is critical. Some people can face cold water supply but not all and hence you need to solve it as quickly as possible.
Firstly you need to figure out the problem and then implement the possible solution for it. Implement the solution and try to resolve it using your way.
In the end, if you cannot figure out the issue and solve it out, call a plumber or professional who can solve it. Hopefully, now you can tackle the problem tankless water heater water getting cold.
