Why Is My Tankless Water Heater Not Working

Why Is My Tankless Water Heater Not Working

Tankless water heaters are a great addition to the home.  They are also a great investment for your office or home.  They are highly efficient, and they help to save you money when it comes to heating water. (Here’s a helpful guide to water heaters)

Although, it is possible for uncommon issues, which is common at the same time, to appliances, to arise. In this article, six problems were noted to be associated or common with the tankless water heater. They are; flame failure, ignition problem, cold water sandwich, mineral buildup, and exhaust blockage.

Why Is My Tankless Water Heater Not Working

Once these problems arise how do you even fix them?


1. Mineral Buildup

Your Tankless water heater is not working because of MINERAL BUILDUP inside your water heater. You will always encounter this problem even if you use a traditional water heater or a tankless one. You simply need to keep an eye on your water heater and watch out for mineral buildup’s. Hard water has a high mineral content and the harder your water, the higher the mineral buildup.

Calcium and magnesium ions are the two minerals that causes these buildup, this, impairing the function of your water heater. To avoid damage, always flush your water heater every six months with a water heater cleaner or preferably with, Ecotemp Ez flush system cleaning kit. However, you can also use a water softener to slow the chemical buildup.

READ:How Does A Hot Water Tank Work

2. Overload

Your tankless water heater capacity as a result of too many showers running, can OVERLOAD your water heater. Your water heater may begin to struggle in other to supply the hot water needed or even shut down as a result of system overload. If this happens, you should try to, reduce the demand for hot water.

This can be done by reducing simultaneous applications, and you could also reset your unit. Another option is to, upgrade to a tankless water heater with a larger capacity or you can add a second unit as well. Adding a second unit will help you save money in the long run.

3. Cold Water Sandwitch

If your water heater consistently takes the shower back to back, you will be familiar with the cold water sandwich problem. This is how cold water sandwich works. Supposing a member of your household just finished using the shower, and it’s your turn, then you turn on the shower, expecting to feel warm water at first but you get blasted with cold water for several seconds before the temperature of the water switches back to warm.

What really happened was that, when the first shower ended, the initial warm water you felt when your shower began, was the trapped water which was on its way to the shower. So after the trapped water was used up, you were then, left with several unheated water. Unfortunately, there is no way to prevent this but once you are aware of this problem, you can wait for some few seconds after turning on your shower, so that the cold water can pass. Then you return to shower, when the temperature switches.

4. Exhaust

Your exhaust might be blocked. For some tankless water heaters, it will present an error code on the display to inform you that your EXHAUST IS BLOCKED. This also means that your water heater is having problems with combusting air or venting. First of all, inspect all the vent pipes to be sure that they are well connected and free from puncture holes.

Always refer to your manufacturer’s manual to be sure that the requirements on the product are being met. Because installing your water heater too close to other objects has the tendency of blocking the air supply hence, creating a fire hazard. Also rodents, or even bird nests and wasps nest can block your venting pipes. So be sure that you take out time to thoroughly examine all vents that are either located or led outside your home.

5. Ignition

Your IGNITION CAN FAIL. your water heater can simply fail to ignite. Although this issue is always caused by the gas supply. So check your propane tank carefully, if it is full before you go ahead to do anything else. If your gas or water valves aren’t fully opened, this can cause the ignition to fail. So check the valves fully.

However, if these steps do not solve the problem, then it could be that your ignition pack has failed or a bigger problem surfaced. At the point, you should conduct a technical expert to help solve the problem and order replacement parts if some parts needs to be replaced.

READ: Best Under Sink Water Heater Reviews

6. Flame Failure

Another vital reason why your water heater is not working is because, it has FLAME FAILURE. you see, flame failure, just like ignition failure can be caused by a low propane tank.

However there are other possible causes of flame failure. They include, a small gas line that is, a gas line that is too small. Another cause of flame failure is, regulator failure, combustion problems, venting etc. But you should contact a technical expert troubleshoot and discover the possible problems attached to this.


In conclusion, your tankless water heater although, provides hot water on demand, but sometimes you will observe that the water will not just get hot no matter how long you leave your tap running. When this happens, it is possible that you have an issue with what is called, the fuel source. If the water heater doesn’t get fueled, then it can’t ignite and warm your water up. If you are using an electric water heater, simply check your breaker box. It is possible that a fuse on the outlet has blown. If you also have a gas water heater, ensure that the gas supply is turned on for the sake of the water heater. So if everything looks like it is supposed to be, then call in a technical expert to troubleshoot.

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