Tankless Water Heater Shuts Off During Shower

Tankless water heaters, as their name indicate, do not contain large tanks for hot water storage. These contain the heating filament that raises the temperature of moving water when you turn on the fixture.

A Tankless water heater can shut off during the shower due to insufficient water from cold pipes, multiple fixtures used simultaneously, low gas or electricity fluctuations, and faulty thermostats. Moreover, it can happen due to a bad thermostat, damaged heating element, mineral accumulation in the heat exchanger, and failure of flow sensors.

Identifying and fixing the water heaters is necessary because taking baths in cold water during winter is challenging. Moreover, it is an unpleasant situation when cold water suddenly comes from the shower heads.

Problems Solutions
Insufficient water from cold pipes Inspect plumbing pipes
Multiple fixtures use at the same time Turn off the hot water fixtures during showering
Low gas or electricity fluctuations Ensure proper gas and electricity supply
Faulty thermostat Hire professional for thermostat replacement
Issues with the heating element Clean the heating element with a wire brush
Mineral accumulation in the heat exchanger Add new heat exchangers
Failure of the flow sensor Replace the flow sensor or switch

Insufficient water from cold pipes

These tankless water heaters do not contain large water tanks to save and supply hot water to the connected fixtures.

These are known as on-demand heaters because they are turned on instantly according to the people’s needs and then shut off.

The cold water from the plumbing pipes runs into the system, and the heating element increases its temperature. Sometimes the supply of these fixtures shuts off because of the issue with cold water pipes.

The supply from cold pipes is limited because of the clogging issues in the old pipes. In addition, the sediments and minerals build on the pipes’ side walls and narrow them.

Water cannot move through them with great pressure. In addition, the issue also comes from the leakages in pipes.

The loose connections and corrosion on galvanized steel increase the risk of leakages in these pipes.

In addition, the supply is also restricted because of clogged filters. The filters are located at the start of the inlet to prevent the heaters from sediments and mineral buildups.

These filters can get clogged because of mineral buildup and restrict the supply. Replace the filters located on the inlet hoses with new ones.

Remove the corroded and cracked pipes or seal them with epoxy materials. Tight the loose connections of the pipes using a wrench.

Multiple fixtures use at the same time

The tankless water heaters have a limited supply and cannot function when you overload the system. In addition, many people use multiple fixtures simultaneously, which can lead to the shutting down of the system.

These can turn off during showering when you turn on the kitchen and laundry area faucets.

It works on the limited flow rate principle, and you can get cold and Luke warm water from the faucets when you exceed the limited flow rate value.

Using multiple hot water fixtures overwhelms the system and can turn off the heating element. Avoid running other hot fixtures like washing machines, dishwashers, and sink faucets when you are bathing to resolve the problem.

Low gas or electricity fluctuations

The tankless water heaters in your home use natural gas, propane, and electric supply for their functioning. These sources help raise the heating element’s temperature for a warm water supply.

Sometimes there is less gas in the propane tank which cannot power the ignition system. Moreover, the gas regulator can also fail and cannot supply sufficient natural gas for their ignition.

The gas pipelines can also get clogged and restrict the supply. In addition, many people face freezing gas line issues in winter, which can cause the heaters to shut off.

The faulty electric connections and fluctuating current supply also cause them to turn off; you can see cold water in faucets. The problem comes because of a power outage, which can cut down your home’s power supply.

The tripping of circuit breakers in your homes restricts the current supply and causes their failure. Check the pipelines and gas regulating valve to solve the problem.

Ensure that circuit breakers in your homes are not tripped and supply power.

Faulty thermostat

The thermostat is a small device that controls the temperature of tankless water heaters. It shuts down the heating source after receiving the required water temperature.

Sometimes these become faulty and turn off the system unevenly during showering. People use cold water for bathing, which is highly unpleasant during winter.

These electronic devices fail to perform their function because of faulty wiring and electrical connections. For example, the loose and broken wires of the thermostat make them faulty and lose their functionality.

People can also face the issue because faulty pressure valves monitor the water pressure and keep them at a specific range.

You can call the professionals to diagnose these components and replace the thermostat and pressure valves.

Issues with the heating element

The heating element of the tankless water heaters works differently compared to the ones that contain larger and insulated tanks for storing warm water for future use.

These tankless water heaters contain a large and strong heating element for filling large containers. In addition, these devices have a small but powerful part to heat the water on demand of people.

The heating elements are prone to failure because of the continuous heating of alloy material. In addition, mineral deposits on their surface from hard water lead to their failure.

Clogging can hinder the functioning of this component, and it cannot heat the water. The heaters can turn off when you are taking a shower because of the failure of their components.

You can replace the heating element with new ones to resolve the issue. Moreover, you can also clean the heating element and remove corrosion and mineral buildup from its surface.

Use the wire brush to scrub their surface and treat them with vinegar and baking soda solution.

Mineral accumulation in the heat exchanger

The heat exchanger is a small device fitted in the tankless water heater to supply heat from the ignition system to the water. Most of the tankless types contain copper-based heat exchangers to raise water temperature.

The water constantly moves over these devices and ends up clogging them. In addition, the hard water from your home’s water tank increases the risk of their failure.

Mineral content in the hard water leaves their dry residues on the heat exchanger and leads to their malfunctioning. These are also susceptible to cracking because of the high temperature of the source.

Moreover, corrosion can also come on their copper element because of water exposure. These are not repairable, and you have to replace the failed heat exchangers because these are the central component of the heaters.

Failure of the flow sensor

The flow sensor is the component of the tankless heaters to identify the water supply. It turns on the heating element after detecting the pressure in the plumbing lines.

The system activates to heat the water and raise its temperature according to the demand of the people. However, the failure of sensors leads to sudden fluctuations in water temperature.

The failed sensor cannot activate the ignition system. Moreover, it can also shut down the flow in the connected fixtures. The failure of the flow sensor or switch comes from their old age and mineral accumulation on their surface.

In addition, corrosion can also come on them and cause the deterioration of the sensors or switches. Replace the corroded flow switches with new ones for the proper functioning of the heating system.

Call the expert plumber for their careful removal and installation. You can find these devices near the inlet hose of the tankless heaters.

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