Bosch Tankless Water Heater Troubleshooting

The tankless water heaters of Bosch use “on-demand” technology which makes them a lot smarter and more energy efficient. Essentially, the device only heats water when you need it and it’s off when you don’t need it. This is unlike conventional tanks that work 24/7 even when there is no demand and that is a waste of energy and money.

But even if Bosch designed their tankless water heaters to be advanced machines that can help homeowners save money, their products are not free from slight malfunctions. Having slight problems with a machine designed to be of the highest caliber is not unusual. The good thing is, minor issues can be solved without having to call in a technician for assistance.

This is what this article is for: to guide you on how to deal with simple issues relating to your Bosch tankless water heater.

Knowing How To Troubleshoot Simple Issues Saves Time And Money

While you may prefer to call in professional help when your water heater starts acting up, know that you can save a lot of money and time by trying out a few solutions by yourself. The issue might simply be solved by turning a switch on and off again and you’ve just spent good money on something you could have solved yourself.

This is not saying you should solve everything on your own, but once you run into issues with you water heater, it’s best to exhaust all possible causes before you call a technician to take a look at your device. This way, you can save precious time waiting for the technician to arrive and you can use the money to pay them for something you need for home or for your personal use.

Common Problems With Bosch Tankless Water Heaters And Their Solutions

Here is a list of the issues you will most likely encounter with your Bosch water heater along with how to deal with it:

Issue: The burner does not ignite when hot water is turned ON

If a two-digit code is displayed, refer to the manual that came with your water heater or download the exact one on their official website. But if there is no code displayed, try the following:

  • Verify power to outlet. Make sure that the heater power button is ON.
  • Make sure the fuses in the control board are good. You need to remove the control board to access the fuses.
  • Check if the cold water inlet connection is plumbed to the right side of heater when facing unit.
  • Confirm that there is at least 0.5 gallons per minute flow of water (the minimum amount of hot water needed to activate the heater). You can verify this by timing how long it takes to get a container filled. Here’s a rough guide: a quart container will take about 23 seconds or less to activate heater.
  • Clean the inlet filter screen.
  • Check the water path for obstructions. Shower heads, faucet aerators and whole house filters should all be clear of debris.
  • Check for plumbing crossover. When this happens in the hot and cold plumbing pipes, back pressure is created on the water flowing through the heater. As such, there will be a higher flow rate than normal needed to activate the heater.
  • Remove the front cover of the heater with the power button on OFF and the power supply unplugged.

Issue: The water is too hot

  • The chosen temperature on the heater is too high. Try lowering the output temperature and see if it changes anything.
  • Clean the inlet filter screen. Doing this can increase flow through the heater.
  • Check to see if there are any obstructions in the water path. All shower heads, faucet aerators and whole house filters should be clear of debris.
  • Make sure that the gas type of the heater is the same with the type of gas that is being supplied.
  • Clean all shower heads and faucet aerators to avoid restrictive outlets. You might also want to upgrade the shower head to one with a higher flow rate as long as it’s allowable by local code.
  • You might need periodic descaling if you live in an area where water has a high mineral content.

Issue: The water is not hot enough

  • Check the selected temperature if it’s not too low. Adjust this to a higher setting and see if it solves the problem.
  • Clean the inlet filter screen as this can increase flow through the heater.
  • Check to see if the water path has any obstructions. Make sure that all showerheads, faucet aerators and whole house filters are clear of debris.
  • Verify that the gas type of the heater is similar to the gas that is being supplied.
  • Check the inlet gas particle screen for blockage. This can be done by looking at the gas inlet connection located at the bottom of the heater.
  • Make sure that the gas pressure follows what was specified in the manual. If you need a reading, you have to call your original installer or a local certified gas technician to do so.
  • Check for a plumbing crossover.

Issue: There is low water flow or pressure

  • There might be too many hot water applications used altogether. Or, there is too much flow being demanded. Your heater can support two 2.0-2.5 GPM shower heads simultaneously or multiple sink applications. A greater draw leads water pressure to drop and flow in the taps will be reduced as well.
  • Make sure that gas pressure follows the specifications listed in the manual. You may need a gas pressure reading for this and you need a gas technician to do this.
  • The temperature selected on the heater might be too high for the flow rate being demanded. If so, the motorized water valve of the heater will close which leads to reduced hot water flow rate. The unit does this so that it can reach the selected output temperature. You can try to lower the temperature to allow the valve to open up to increase water flow rate.
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