EcoSmart Water Heater Not Getting Hot [Reasons + Solutions]

Your EcoSmart water heater not getting hot is happening due to the faulty heating element. For that, inspect the heating element and then replace it if needed.

However, there are plenty of reasons behind this issue. These are:

  • No Power
  • Internal Parts Failure
  • Low Or High Voltage Rate
  • Using Too Much Cold Water
  • Voltage Less Than 240V
EcoSmart water heater not getting hot

Keep reading to find out all about these issues and learn how you can solve them in detail. Let’s get started!

EcoSmart Water Heater Not Getting Hot [Reasons + Solutions]

Under this segment, you’ll learn about the troubleshooting method for fixing the not heating up issue of the EcoSmart tankless water heater. Here’s the detail:

1. Faulty Heating Elements

Sometimes the heating elements don’t work causing the EcoSmart water heater to operate at all. It happens because one of the parts can’t get power.

faulty heating elements

In that case, you’ll need to use a volt meter and test out its power to determine whether the elements are working or not.

How To Fix:

To troubleshoot the issue, you’ll need to check the heating elements using a voltmeter. Here’s how to do it yourself:

  • Start by, opening the case of the water heater cover. Then, locate the heating elements compartment.
  • You’ll find 2 red wires that connect to each element. To check whether it’s working or not, turn on the hot water tap. It would be better if you run the shower or sink.
  • Next, the digital screen would illuminate and show the temperature setting on the unit. Now, get the volt meter and place one probe on one screw while holding the other probe on the other screw.
  • The volt meter will show a voltage reading between 220V – 240V.

During this period, you’ll need to check the LED display and shower whether the water is running through the unit or not. Next, look at the voltage reading. 

If the volt meter shows 0 voltage when holding the probes on each screw, open the circuit breaker cover and turn off the breaker of the water heater. 

Then, set the volt meter for ohms. Again, put one probe on one screw and the other probe on the other screw. Based on the scenarios, do the following action:

  • If the voltage reading is 6 – 10 ohms, it indicates the element is good but requires professional help to fix the bug. Contact EcoSmart Support.
  • If the voltage reading is lower than 5 or higher than 10, it means you need to replace the element. 

Don’t panic! You can easily replace the faulty element by opening the water heater cover and then removing the red wires by detaching the screws. 

Then remove the elements by using a wrench and install the new one. Next, place the red wires back in their spot and tighten out the screws. Lastly, attach the water heater cover by inserting the 4 screws.

To understand the process better, I suggest checking this tutorial:

Note: Due to air pockets, sediment buildup, or freeze damage, the element can go bad.

2. No Power Coming To The Unit

Mainly, there are three main culprits for no power generating to the unit and so the EcoSmart tankless water heater not working. These are:

  • Faulty fuse: If the fuse goes out, it can cause the unit to not work at all.
  • Bad circuit breaker: Due to this, the unit doesn’t get electrical power.
  • Incorrect wiring connection: During the installation period, placing the red and black wires in the wrong post can cause this issue.

How To Fix:

When these are the root causes, the digital screen light won’t turn on and the water would be the same as the cold state. To repair the no-power issue, here are some solutions:

i). Replace Faulty Fuse

  • Turn the circuit breaker in the OFF position. Also, switch off the power supply for the room.
  • Detach the water heater cover after taking out the screws.
  • Locate the fuse holder area.
  • Remove the 4 screws from the fuse holder.
  • Find the small fuse. If the fuse is 250V (3 Amp), then you’ll find it in the top section. However, if the fuse is 250V-200-400 mA, then locate it on the upper left side.
  • Pull it out from the fuse compartment and insert a new fuse in its place.
  • Reinstall all the parts back to their respective spot.

ii). Change The Bad Circuit Breaker

  • Remove the water heater cover and then turn off the power supply to the room which contains the EcoSmart tankless water heater.
  • Then, open the circuit breaker cover and locate the water heater breaker. After you find them, use a white marker, and mark them.
  • Take a screwdriver and detach all the screws from the circuit breaker. Be sure to keep them in a safe zone to avoid losing the screws.
  • Remove the wire from the breaker and detach it. Next, insert a new breaker in the right spot and place the wires inside the hole. Attach the screws and tighten them out with the same tool.
  • Insert the circuit breaker cover and turn on the power supply. After that, test out whether the water heater gets hot or not.

Note: In Eco 8 and 11, it requires one breaker. However, other models need 2 or more breakers for the water heater. So, test all the breakers to find the faulty one.

iii). Properly Connect The Wiring Harness

  • Remove the EcoSmart water heater cover using a hand after unscrewing the screws.
  • Find the wiring harness.
  • If the size of the wire is incorrect, you’ll need to remove the red and black wires from the terminal block after detaching the screws. Then, completely remove the wires and install them nicely.
  • However, if the wires are placed wrongly, remove the screws using the screwdriver and detach the wires.
  • Next, check where the wires are designed to be set.
  • Arrange them in the right direction. For example, you’ll need to insert the black wire in the L1 terminal and the red wire in the L2 terminal.
  • Then, insert the screws and tighten them out using the screwdriver.

Note: In the EcoSmart tankless water heater manual, it is suggested to use 8 AWG or higher-size wires.

3. Internal Parts Not Operating

If the internal parts like the thermostat, flow sensor, and so on turn bad, it can cause these components to not work at all.

 internal parts not operating

Due to this, the EcoSmart tankless water heater not getting hot. You’ll find the water the same as the natural state and the digital screen will lighten up to indicate this issue.

How To Fix:

Most internal part issues can’t be fixed at home as it requires expert help. To figure out whether it’s an internal part issue or not, do the following steps:

  • Test out the power using a multi-clamp voltmeter. 
  • After ensuring that the heater gets the electrical power, it simply indicates that internal parts fail.

To troubleshoot the faulty flow sensor, here’s how you can do it easily:

  • Turn off the power supply. Then, open the water heater cover after unscrewing all the screws. Test out the voltage using a voltmeter. 
  • Locate the flow sensor. Use a wrench to remove the pipe that holds the flow sensor and remove it. Be sure to remove the cable.
  • Detach the flow sensor and insert a new one. Put everything back in place and finish the process.

You can also watch the below tutorial to replace the flow sensor. 

Note: To repair other internal part issues, you’ll need to contact EcoSmart Support by visiting their website to inform them about the issue. You can also call them at 1-877-474-6473 number or email them at to get urgent help.

4. High Or Low Flow Rate

Another reason the EcoSmart water heater is not heating is either the flow rate is too low or high in the water heater. In the case of a high flow rate, you’ll see an E5 error code in the LED control board. 

Check if the flow rate is high or low like this and then either lessen or raise the rate:

  • From the temperature set point display (ON), click and hold the button for around 10 seconds. Then, you’ll find the diagnostics screen.
  • Twist the round knob to the left side 2 times to get the current flow rate display.
  • Locate the hidden decimal points from this display. Like, F005 = 00.5 GPM, F049 = 04.9 GPM, or F101 = 10.1 GPM.

How To Fix:

After knowing whether the flow rate is too high or low, you’ll now need to solve the bug. Here’s the direction:

i). Increase The Flow Rate

  • Insert an EcoSmart Flow Regulator on the outlet connection of the water heater. 
  • Raise the flow rate. This will help balance the water pressure as well.
  • After that, simply remove the flow regulator and enjoy the water supply.

ii). Decrease The Flow Rate

  • Check the LED control board. If it shows an E5 error code, then you’ll need to slow down the flow rate.
  • Attach an EcoSmart Flow Restrictor on the outlet or inlet connection of the water heater.
  • Lessen the flow rate and then remove the flow restrictor.

Be sure to pick the right size of the EcoSmart Flow Regulator or Restrictor based on the inlet water temperature and outlet temperature of 105°F. Here’s the table of inlet water temperature and suitable restrictor size:

Model40°F50°F60°F70°FEcoSmart Flow RestrictorConnection Size
ECO IFR 1-21/2″ Compresion
ECO IFR 1-21/2″ Compresion
ECO IFR 3-43/4″ NPT
ECO IFR 3-43/4″ NPT
ECO IFR 3-43/4″ NPT
ECO 363. IFR 3-43/4″ NPT

Note: It’s suggested to have an activation flow rate of about 0.3 GPM (Gallons Per Minute).

Why Is The Water From My Faucet Not Hot Enough?

If the water coming from the faucet is not as warm as the temperature setting of your water heater, it mostly happens due to 4 reasons. Let me explain it in detail:

If the EcoSmart water heater works fine but the water isn’t getting hot, it’s possible that the voltage is less than 240 volts. In this case, you’ll get an S103 error code in the display to inform you about this issue.

Due to this, it can cause the water heater to not get hot as the unit receives less power.

How To Fix:

Check if the circuit breakers are connected properly or not. If everything seems okay while the screen shows an S103 error, you’ll need to change the water heater as this can’t be fixed.

If your home electrical line has less than 240 volts, this can sometimes cause the water heater digital display to read slightly less than the temperature setting you have set.

In that case, escalate the temperature setting higher than the actual output temperature.

2. Turned On Anti-scald Feature Or Tempering Valve

If your water heater contains an anti-scald feature or a tempering valve, it can automatically mix cold water even if you move the adjustment knob to the full hot.

How To Fix:

To fix the issue, just turn the anti-scald feature or tempering valve off. And then, simply raise the temperature setting to get the desired hot water.

3. Thermal Loss

Thermal loss usually occurs when the hot water goes through the hot water delivery system to your faucet. 

How To Fix:

This happens when the distance is long to reach the faucet or the pipes are cold.

It’s not a big deal to get tense. You can fix the bug by raising the temperature to get the hotter water source.

4. Adding Too Much Cold Water

A common mistake we often make is mixing cold water with the tankless water heater which causes the issue of the EcoSmart water heater not heating temporarily.

How To Fix:

This error is fixable and you don’t need to do much. Just turn off the anti-scald feature on your faucet and let it reduce the amount of mixed cold water easily.

How To Set Temperature On EcoSmart Tankless Water Heater?

For safety against burning your hands, it gets essential to know about the EcoSmart tankless water heater temperature setting. To set it higher or lower, try the given direction:

set the temperature on EcoSmart tankless water heater
  • Press on the adjustment round knob to turn on the display.
  • Click on the adjustment knob for around 3 seconds to change the temperature control from Fahrenheit to Celsius or vice versa.
  • Twist the knob to the right side to raise the temperature or turn it to the left side to lessen the temperature. You can set the temperature from 80°F to 140°F (27°C – 60°C) or higher.

The given chart will help you to know the right water temperature range that is safe for your home:

TemperatureTime Require To Burn Water
120°F5 minutes or more
125°F1 ½ to 2 minutes
130°F30 seconds
135°F10 seconds
140°F5 seconds or less
145°F3 seconds or less
150°F1 ½ seconds
155°F1 second

EcoSmart Tankless Water Heater Maintenance Tips

A lot of times minerals like calcium or magnesium can cause scale forms on the elements or other parts. And so, it causes hot water issues. 

EcoSmart tankless water heater  maintenance

To get rid of these, you’ll need to maintain your heater regularly. Here’s how you can go for 3 steps of maintenance. 

Manual Maintenance: Do it every 6 to 12 months to keep the water heater clean from extremely hard water.

Recirculating Maintenance:  It’s advisable to go for recirculating maintenance once or twice a year based on the hardness of the water supply.

Filtration Maintenance: For filtration maintenance, it can be done if you consult the local water company or an expert to do it

However, to know more about the maintenance, you can read our ultimate guide on EcoSmart tankless water heater maintenance.


Why does my tankless water heater take so long to heat?

Due to the low-temperature setting, the tankless water heater takes longer to heat up. Just increase the temperature to warm it up faster.

How can I increase the heat in my tankless water heater?

To increase the temperature in your EcoSmart tankless water heater, turn the adjustment knob clockwise.

How long does it take for the tankless water heater to heat up?

Depending on the temperature range (80°F to 140°F), it can take 1 second or more than 5 minutes.

How to reset the EcoSmart tankless water heater?

To reset it, turn on the display and press on the adjustment knob for 3 or 5 seconds. Then, you’ll get CE3 mode. Next, run the water for 2/3 minutes.

How to turn on EcoSmart tankless water heater?

You can activate the EcoSmart tankless water heater by pressing the adjustment knob one time.

Ending Note

Before you throw the unit in the trash can, wait for a little while and find out the reasons why the EcoSmart tankless water heater not heating.

Instead of buying a new water heater and blaming the brand, it’s best to do the easy repairs mentioned above. Yes, you might need to spend a few bucks to get a new fuse, circuit breaker, and so on. In the worst case, if the water heater is unrepairable, then replace it.

So, do not wait for the disaster and repair it ASAP! If you have any more queries, don’t hesitate to let us know in the comment box. We will be happy to help you.

About William

William is the founder of He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

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