Bosch Thermotechnology

Water Heaters FAQ

It is important to remember that this is a tankless water heater, and the temperature of the how water that it produces will be affected by:

1. The model that you have installed. We offer a range of point of use electric tankless water heaters, and the heating capacity will vary between the models.

2. The temperature setting that you have selected. Depending on the model installed you will have either a circuit board with a temperature knob on it, or a mechanical flow switch that has a screw that can be loosened and slid to either "LO" or "HI".

Before removing the front cover to make adjustments, please isolate the water heater from the power supply by turning off the correct circuit breaker inside your breaker panel!

3. The flow rate of the hot water fixture that you are feeding from the water heater. In a tankless water heater the cold supply water is heated as it flows through the heating coil, and so the faster the water moves the less heat energy that it will be able to absorb from the heating elements.

If you have selected the highest available temperature setting but the output water temperature is too low for you, then you will need to reduce the water flow rate to allow more heat energy to get into the water before it leaves the water heater. Please refer to the product manual for further details.

If your water flow needs are too high for the model that you have installed, you may need to consider a model that has a higher heating capacity.

4. Supply voltage. Each model has an electrical installation requirement that must be met (please refer to your product manual for further specific details on each model), and if the supply voltage is less than the model requires this can result in a reduced heating capacity.

Example; The Bosch Tronic 3000 US9 model is rated for 240vac. It will work down to 208vac but will lose approximately 25% of its ability to heat the water.

This is a 240vac water heater, and it is strongly recommended that only qualified professionals who are familiar with working with live voltage carry out any work that requires removing the front cover of the water heater.

For Models With A Circuit Board (US12, RP12P, AE12):

1. Isolate the water heater from the power supply by turning off the correct circuit breaker in your breaker panel.

2. Remove the front cover of the water heater.

3. Look for the tall plastic knob that is on the circuit board. Adjust it as needed.

4. Replace the front cover, turn the circuit breaker back on, test the water temperature.

For All Other Models:

1. Isolate the water heater from the power supply by turning off the correct circuit breaker in your breaker panel.

2. Remove the front cover of the water heater.

3. Look for the mechanical flow switch, and you will see a small screw next to a "LO" and "HI" sticker.

4. Loosen the screw enough to be able to slide it to either "LO" or "HI" as desired. Retighten the screw.

a. "HI" setting will use both internal heating elements to heat the water, offering full power.

b. "LO" setting will use only one heating element to heat the water, resulting in 50% power.

c. You must slide the screw fully to either "LO" or "HI", the water heater may not operate correctly if the screw is set in between the two settings.

5. Replace the front cover, turn the circuit breaker back on, test the water temperature.

Note: If you have selected the highest temperature setting for your water heater, and your voltage supply is correct for that model, then you will need to slow the water flow rate down in order to gain a higher output water temperature. Please refer to the product manual for further details.

These are the most common causes for failure to activate with water flow:

1. No power. Please check that the electrical installation is correct for the specific model and that adequate power is being supplied to the water heater.

2. Water flow rate. Each model requires a certain minimum GPM (gallons per minute) water flow through it to activate the internal flow switch. If you have verified that correct power is being supplied to the water heater then it may be the case that your hot water fixture is only allowing a flow rate that is below the minimum needed to activate the water heater. If you can speed the water up to be above the activation rate, the water heater should turn on. Please refer to the product manual for further details.

3. The internal thermal cutout safety device may have tripped. Your water heater contains a safety device that senses the temperature of the copper heating coil, and if an overheating condition occurs this device will trip and prevent power from reaching the flow switch.

To reset the thermal cutout switch:

a. Isolate the water heater from the power supply by turning off the correct circuit breaker in your breaker panel.

b. Remove the front cover of the water heater.

c. Locate the thermal cutout device and press the small button that is in the middle of it. If it clicks in, then the device was tripped.

d. Replace the front cover, turn the circuit breaker back on, test that the water heater now turns on when water is flowing.

No, this water heater is designed and approved to be hard-wired only.

Please refer to the product manual to determine the correct breaker size and wire gauge for your particular model.

Note: If the water heater is installed in a location that is out of the sight of the breaker panel that is supplying it with power, a circuit breaker lockout or additional local means of disconnection for all non-grounded conductors must be provided that is within sight of the appliance. (REF NEC 422.31)

No, this water heater is designed and approved to be supplied with unheated potable water only.

If you are in need of a small water heater that can be used in a booster application, please take a look at our Bosch Tronic 3000T range of mini-tank electric water heaters instead!

Yes:

1. We highly recommend that you use water shut-off valves when installing the water heater. This can help with adjusting the maximum water flow rate through the water heater if you need to increase the temperature of the hot water that it produces.

2. Never use pipe dope to seal the water connections, as it can lead to damage to the flow switch and internal heating elements. Only use teflon tape.

3. Try to keep the pipe as short as possible between the water heater and the hot water fixture that it is supplying.

4. For full installation requirements, please refer to the product manual.

In the event of a water leak:

1. The very first thing that you should do is Isolate the water heater from the power supply by turning off the correct circuit breaker in your breaker panel.

2. Next, turn off the water supply to the water heater. If the water is leaking from inside the water heater, skip to Step 4.

3. If the water is leaking from where plumbing is connected to the water heater:

a. Remove the pipe and inspect it for damage.

b. Inspect the water connection nipples on the water heater for damage.

c. If no damage is evident, wipe clean all water connection surfaces and reconnect the piping to the water heater. If a threaded connection was used, reapply teflon tape to the water heater's threaded connections prior to screwing the pipe fitting back on.

d. Once the plumbing is reconnected, open up water supply to the water heater and check that the leak has stopped.

4. If the water is leaking from where the internal mechanical flow switch is plumbed into an internal copper pipe:

a. Unscrew the two small fittings.

b. Ensure that they are clean and undamaged.

c. Screw them back into place.

d. Open up the water supply to the water heater and check that the leak has stopped.

e. If the leak has not stopped it may be necessary to replace the whole flow switch assembly.

5. If the water is leaking from the body of the internal mechanical flow switch:

a. A new flow switch will be needed.

6. If the water is leaking from the internal copper coil pipe:

a. The water heater must be replaced.

Note: Do not turn the electrical supply to the water back on until any water leaking has been rectified.

No, this water heater contains no parts that require regular maintenance.

The anode rod is a replaceable component inside many water storage tanks, including our electric mini-tank products, and it's purpose is to sacrifice itself over time to protect the water tank from corrosion.

In order to prevent the metal components of the tank from corroding it is important to check the condition of the anode rod regularly, and replace it if it is heavily pitted or dissolved.

Failure to do so can result in premature failure of the water heater.

As the corrosive properties of water can vary from location to location, the frequency of when you should check the condition of the anode rod differs too, but we recommend from six months to annually.

Damage to the water heater that comes as a result of failure to maintain the anode rod will not be covered under warranty.

For further details, please refer to the installation manual that came with your product. If you no longer have your manual, a replacement can be downloaded from our webpage.

Please check the following:

1. Verify that the power switch on the water heater is set to the on position.

2. Rotate the thermostat dial to a hotter position.

3. Verify that your outlet has power by plugging another appliance into it and checking operation.

4. If the above steps still result in the red power light not turning on; Unplug the unit from the outlet, remove the front cover, and look for the high limit reset button that is located on the thermostat.

Push the button with a pointed object;

a. If it clicks, then the high limit was tripped and preventing power from flowing through the thermostat. Replace the cover, plug the product back into the outlet, ensure that the power switch is turned on, rotate the thermostat dial to a hotter setting, and the red light should turn on.

b. If the button was not tripped, and the power switch was on, the thermostat dial was set to a higher temperature setting, and you do have correct voltage at the power outlet, then you may need to replace the thermostat.

For further details, please refer to the installation manual that came with your product. If you no longer have your manual, a replacement can be downloaded from our webpage.

Please check the following:

1. Verify that the power switch on the water heater is set to the on position.

2. Rotate the thermostat dial to a hotter position.

3. Verify that the correct circuit breaker in your breaker panel is flipped to the On position and has not tripped.

4. A qualified contractor who is familiar with working safely on live electrical equipment should ensure that the water heater has been wired correctly to the breaker and has correct voltage feeding into the thermostat.

5. If the above steps still result in the red power light not turning on; Flip the correct circuit breaker in your circuit panel to the Off position, remove the water heater's front cover, and look for the high limit reset button that is located on the thermostat.

Push the button with a pointed object;

a. If it clicks, then the high limit was tripped and preventing power from flowing through the thermostat. Replace the cover, turn the correct circuit breaker back On, ensure that the power switch is turned on, rotate the thermostat dial to a hotter setting, and the red light should turn on.

b. If the button was not tripped, and the power switch was on, the thermostat dial was set to a higher temperature setting, and you do have correct voltage from the breaker to the water heater, then you may need to replace the thermostat.

For further details, please refer to the installation manual that came with your product. If you no longer have your manual, a replacement can be downloaded from our webpage.

If you notice that the hot water coming from the water heater is brown or orange in color, then this could be an indication that the anode rod inside the product is depleted and the tank itself is now corroding.

Please refer to the manual that came with the product on how to check the anode rod. If it is heavily pitted or depleted it must be replaced immediately to prevent the tank corrosion from resulting in permanent damage and a leak.

Damage to the water heater that comes as a result of failure to maintain the anode rod will not be covered under warranty.

For further details, please refer to the installation manual that came with your product. If you no longer have your manual, a replacement can be downloaded from our webpage.

If you notice an unusual egg-like odor to the hot water that is coming from the water heater, this could indicate a reaction between the properties in your water supply and the magnesium anode rod inside the water heater. The odor can be more prominent in properties that are using softened water.

This is not a condition that is caused by the product itself, it is instead a property of the water supply.

You may be advised by some contractors to just remove the anode rod, but we recommend against that as it could result in permanent water damage to the product that would not be covered under warranty.

Where does the water appear to be leaking from?

1. It is coming from where the T&P valve is screwed into the water heater.

a. Isolate the product from the power supply (depending on your exact model, either unplug the water heater from the outlet or turn off the circuit breaker)

b. Turn off the water supply to the water heater.

c. Drain the stored water.

d. Check that the valve has been screwed in and seated correctly.

e. If you notice that the female threads in the tank are corroded then this could be an indication that the anode rod has depleted and the water heater is now being attacked by water corrosion. If this is the case, then the water heater may need to be replaced as once water damage has occurred is it typically not repairable.

2. It is coming from the oval front cover.

a. Isolate the product from the power supply (depending on your exact model, either unplug the water heater from the outlet or turn off the circuit breaker).

b. Turn off the water supply to the water heater.

c. Drain the stored water.

d. Remove the front cover.

e. Remove the heating element and inspect the tank and the opening. If it is corroded then this could be an indication that the anode rod has depleted and the water heater is now being attacked by water corrosion. If this is the case, then the water heater may need to be replaced as once water damage has occurred is it typically not repairable.

f. If the metal of the tank is clean and not corroded, inspect the gasket that sits between the heating element and the tank. If the gasket is damaged it will need to be replaced.

g. If the gasket is undamaged (or you have the new gasket ready) reassemble the gasket and heating element, and ensure that the four bolts are secured down firmly and evenly. Refill the tank to test if the leak is now resolved.

3. It is coming from the bottom, sides, or rear of the water heater. This could be an indication that the anode rod has depleted and the water heater is now being attacked by water corrosion. If this is the case then the water heater may need to be replaced, as once water damage has occurred it is not repairable.

It is important to remember that this product is a water storage tank, and the duration of hot water that you will receive will depend on:

1. The model of water heater that you have installed (we have three product sizes available; 2.5 gallon, 4 gallon, and 7 gallon).

2. The flow rate of the hot water fixture that the water heater is supplying. Higher flow rates will result in a shorter duration of hot water available to you for each use.

3. When the hot water is depleted it will require approximately 20 minutes to get back up to temperature inside the water heater tank. This recovery time will vary based on the temperature of your cold water supply and the setting that you have selected on the thermostat dial.

That will depend on the age of the water heater, and the exact location of the water leak, see below (This is a 240vac water heater, and it is strongly recommended that only qualified professionals who are familiar with working with live voltage carry out any work that requires removing the front cover of the water heater):

Models that contain two or three canisters that are made from copper:

1. The canisters are non-replaceable, and the water heater will need to be replaced.

Models that contain two or three black plastic canisters with brass heating assemblies mounted on top of them:

1. If the water is leaking from on top of a brass element assembly, or from where a heating element enters the brass assembly; The brass assembly must be replaced. Please refer to your product manual to identify the correct part# for the specific assembly that is leaking.

2. If the water is leaking from the joint between the black plastic canister and the brass assembly; There is an o-ring that seals the joint, and this may have been compromised. Please refer to your product manual to identify the part# for a replacement o-ring.

3. If the water is leaking from a hole or a crack in the black plastic canister; This is a non-replaceable part, and the water heater will need to be replaced.

This is a 240vac water heater, and it is strongly recommended that only qualified professionals who are familiar with working with live voltage carry out any work that requires removing the front cover of the water heater.

These are the most common causes for failure to activate with water flow:

1. No power. Check that the electrical installation is correct for the specific model and that adequate power is being supplied to the water heater. Please refer to the product manual for further details.

2. Water flow rate. Each model requires a certain minimum GPM (gallons per minute) water flow through it to activate the internal flow switch. If you have verified that correct power is being supplied to the water heater then it may be the case that your hot water fixture is only allowing a flow rate that is below the minimum needed to activate the water heater. If you can speed the water up to be above the activation rate, the water heater should turn on. Please refer to the product manual for further details.

3. Water supply pressure. If your property is on a city water supply, this product requires a minimum of 30psi to operate correctly. If you are on a well, the minimum pressure range required is 30psi - 50psi.

4. Dirty inlet water filter. To protect the water heater from particles in the water supply, there is a small mesh water filter located up inside the cold water inlet fitting. Refer to your product manual on how to remove and check the filter.

5. Stuck flow transducer. This is a component inside the water heater that measures the flow rate of the water that is running through the water heater and uses that information to adjust the power to the heating elements. The flow transducer is a clear plastic tube that is located just above the point where the cold water connection enters the metal water heater chassis.

As the plastic is clear you should be able to see the impeller inside spinning when water is flowing (shining a flashlight on it may help). If the impeller does not start and stop when water flow starts and stops then the water heater will not turn on when water is flowing.

Please refer to the product manual for further details.

6. Reversed plumbing connection. This seems too obvious, but our technical support teams frequently run into this when assisting customers! If this is a new installation then make absolutely certain that the cold water supply pipe is connected to the water heater's cold water inlet connection and not the hot outlet connection.

7. Plumbing Crossover. Mixing valves in the home's plumbing (shower valves, single-handed faucets, washing machine valves) can fail internally and result in cold water bleeding over into the hot water lines, and this can affect the operation of a tankless water heater. Please refer to the product manual for details on how to test for this condition.

This is a 240vac water heater, and it is strongly recommended that only qualified professionals who are familiar with working with live voltage carry out any work that requires removing the front cover of the water heater.

If the water heater is turning on with water flow but the output water seems to be cooler than expected, these are the most common causes:

1. The temperature adjustment knob is set too low. The location of the knob is different depending on the version that you have installed:

a. If the water heater has a display screen on the front panel, the temperature control knob is located just below the screen.

b. For models that have no display screen, the temperature knob is located on the underside of the water heater next to the cold water inlet plumbing connection.

2. One or more thermal cutouts may have tripped. Each of the heating modules inside the water heater has a thermal cutout switch mounted on top of it which senses the temperature of the brass heating element assembly below it. If the assembly begins to overheat the thermal cutout will trip and electrical power will stop flowing to the heating elements. Please refer to the product manual for the reset procedure.

3. Water flow rate. While a flow rate that is too low will result in the water heater not activating when water is flowing, a flow rate that is too high will result in the water heater not being able to heat the water to the temperature that you are looking for. Please refer to the product manual for further details.

4. Water supply pressure. If your property is on a city water supply, this product requires a minimum of 30psi to operate correctly. If you are on a well, the minimum pressure range required is 30psi - 50psi.

5. Plumbing Crossover. Mixing valves in the home's plumbing (shower valves, single-handed faucets, washing machine valves) can fail internally and result in cold water bleeding over into the hot water lines, and this can affect the operation of a tankless water heater. Please refer to the product manual for details on how to test for this condition.

These are the most common causes of the water being too hot:

1. The temperature control knob is set too high. The location of the knob is different depending on the version that you have installed:

a. If the water heater has a display screen on the front panel, the temperature control knob is located just below the screen.

b. For models that have no display screen, the temperature knob is located on the underside of the water heater next to the cold water inlet plumbing connection.

2. Dirty inlet water filter. To protect the water heater from particles in the water supply, there is a small mesh water filter located up inside the cold water inlet fitting. Refer to your product manual on how to remove and check the filter.

3. One or more heating elements defective. Please refer to the product manual for further details and testing procedure (this must be carried out by a qualified person who in familiar with working with electrical equipment).

No, this water heater is designed and approved to be hard-wired only.

Please refer to the product manual to determine the correct breaker quantities and sizes, and wire gauge, for your particular model.

Note: If the water heater is installed in a location that is out of the sight of the breaker panel that is supplying it with power, a circuit breaker lockout or additional local means of disconnection for all non-grounded conductors must be provided that is within sight of the appliance. (REF NEC 422.31)

No, this water heater is designed and approved to be supplied with unheated potable water only.

Yes:

1. We highly recommend that you use water shut-off valves when installing the water heater. This can help with adjusting the maximum water flow rate through the water heater if you need to increase the temperature of the hot water that it produces.

2. Never use pipe dope to seal the water connections, as it can lead to damage to the flow switch and internal heating elements. Only use teflon tape.

3. For full installation requirements, please refer to the product manual.

We recommend that the inter water filter be checked and cleaned annually to ensure that it does not become blocked. Please refer to the product manual for further instructions.