Rheem Tankless Water Heater Troubleshooting: Quick Fix Guide For Common Issues

rheem tankless water heater troubleshooting

Rheem tankless water heaters are a modern solution for providing your home with an endless supply of hot water from your hot water faucet. Unlike traditional water heaters that continuously heat and reheat water to keep it hot, tankless models heat water on demand, which can lead to energy savings.

However, like any sophisticated appliance, they may occasionally encounter issues that require troubleshooting. Being familiar with common problems and solutions can help ensure your Rheem operates efficiently and lasts for many years.

Understanding how to troubleshoot your Rheem tankless water heater is essential for maintaining its performance and avoiding the inconvenience of unexpected cold showers. Our Rheem tankless water heater troubleshooting guide will be your answer.

Whether you’re faced with fluctuating water temperatures, error codes on the display, or issues related to power and gas supply, knowing how to diagnose and resolve these problems can save you time and money. Regular maintenance is also key to preventing issues before they start and keeping your water heater running smoothly.

Key Takeaways

  • Understanding common issues can prolong the life of your Rheem tankless water heater.
  • Efficient troubleshooting techniques can save both time and costs on repairs.
  • Regular maintenance is crucial for optimal performance of your water heater.

Understanding Your Rheem Tankless Water Heater

Rheem tankless water heaters are popular choices for their efficiency and compact design. When considering a model, you have several options, each with unique specifications to fit your needs.

Performance Series: Ideal for smaller households, these models provide a continuous supply of hot water on demand. They come in varying capacities, typically measured in gallons-per-minute (GPM), so you can choose one that best matches your household water usage.

Professional Series: These are a step up, offering advanced features such as recirculation pumps, which provide quicker hot water delivery, and higher GPM rates, suitable for larger families or multiple fixture use.

Here’s a quick explanation of terms you may come across:

  • GPM: Gallons Per Minute, a measure of how much hot water the heater can deliver at one time.
  • Condensing Technology: This tech allows the heaters to be more efficient, reusing heat from the exhaust to warm the water, thereby lowering energy costs.

Rheem hot water system also incorporates innovative technologies like EcoNet®, which gives you the convenience of controlling your water heater remotely, and self-diagnostic systems for easier maintenance.

Here’s what you need to keep in mind about the technology specifics:

  • Recirculation pumps save you time by providing hot water faster.
  • Self-diagnostic systems make troubleshooting more straightforward and less of a hassle.

When choosing your Rheem tankless water heater, consider the size of your home, your hot water usage, and how the technology can contribute to your household’s comfort and convenience.

How To Reset Your Heater?

Resetting your Rheem Tankless Water Heater can often resolve minor issues and restore normal operation. Follow these steps to reset your heater:

1. Power Off:

  • Locate the power source for your water heater and switch it off. This could involve turning off the power switch near the unit or shutting off the circuit breaker in your electrical panel.

2. Wait:

  • Allow the unit to remain powered off for at least 5 minutes. This time allows the internal components to reset completely.

3. Power On:

  • After the waiting period, switch the power back on. If you turned off a switch near the unit, flip it back to the “On” position. If you shut off the circuit breaker, flip it back on.

4. Monitor Operation:

  • Once power is restored, observe the operation of your water heater. Listen for any unusual sounds and watch for error codes on the display panel, if applicable.

5. Test:

  • Run hot water from your faucets to ensure the heater is functioning correctly. Check for any improvements in flow rate or temperature consistency.

6. Consult Manual:

  • If the issue persists after resetting the heater, refer to the owner’s manual for troubleshooting guidance. It may provide specific instructions for addressing common problems.

7. Professional Assistance:

  • If you’re unable to resolve the issue on your own or if you encounter error codes indicating a more serious problem, contact a qualified technician for assistance. They can diagnose the issue accurately and perform any necessary repairs.

By following these steps, you can effectively reset your Rheem Tankless Water Heater and troubleshoot minor issues that may arise.

Common Error Codes and Solutions

When your Rheem tankless water heater displays an error code, it’s an invitation to troubleshoot. Let’s look at common error codes you may encounter and straightforward solutions for each.

Ignition Failure

If you see an error code indicating ignition failure, this typically means the heater can’t light the burner. First, check your gas line supply – ensure it’s turned on and that you have proper pressure. If gas supply is fine, cleaning the ignition elements may resolve the issue.

Flame Rod Issues

For flame rod issues, error codes often pop up when the flame rod is dirty or improperly positioned. Gently cleaning the flame rod with a soft cloth and confirming its correct placement can help extinguish these error messages.

Air Supply or Exhaust Blockage

An error related to air supply or exhaust blockage suggests that the heater is having difficulty with ventilation. Inspect the air intake and exhaust vents for any obstructions and remove them carefully to restore proper airflow.

Temperature Sensor Malfunction

Encountering a temperature sensor malfunction could mean the sensor is either faulty or in need of a recalibration. Try resetting the sensor, and if the problem persists, it may be time to replace the sensor itself.

System Overload

A system overload error code can surface when the demand for hot water exceeds the heater’s capacity. Try reducing the simultaneous use of hot water appliances. If overloading continues, it might be necessary to assess whether a heater with a greater capacity is needed.

No Hot Water

If you find that only cold water flows from your hot water faucet, it could indicate a problem with your tankless water heater’s heating function. If your water heater is electric, and doesn’t generate hot water even after being on for a while, chances are the electric heating elementis not working.

Maintenance Essentials

To ensure the longevity and efficient operation of your Rheem tankless water heater, it’s crucial to carry out specific maintenance tasks regularly. These tasks will help avoid common issues like mineral build-up, system overload, and filtration problems.

Regular Cleaning

Your tankless water heater requires routine cleaning to keep it running smoothly. Begin by turning the unit off and removing any debris from the exterior. For the internal components, refer to your Rheem’s manual for instructions on safe cleaning practices.

Regular cleaning helps maintain the unit’s efficiency by preventing dust and dirt from hindering its operation.

Filter Replacement

The water filter in your Rheem tankless water heater is your first line of defense against impurities. It’s important to replace the filter every 3 to 6 months, or more frequently if you have hard water or high usage. A clean filter safeguards the unit from clogs and maintains an optimal flow rate.

  1. Locate your filter—usually at the inlet.
  2. Shut off the water supply.
  3. Carefully remove the old filter.
  4. Insert a new filter and secure it in place.
  5. Turn the water supply back on.

Descaling Process

Descaling is key to tackling mineral buildup—a common issue in areas with hard water. Perform descaling at least once a year, or as directed by your user manual. Use a professionally recommended descaling solution and follow these steps:

  1. Turn off the unit and disconnect the electrical power.
  2. Attach a hosing line to the water valves.
  3. Allow the descaling solution to circulate through the system as per product directions.
  4. Flush the system with clean water to remove any residual solution.

Adhering to these maintenance essentials will help keep your Rheem tankless water heater in top condition.

Troubleshooting Flow Rate Problems

When dealing with flow rate issues in your Rheem Tankless Water Heater, it’s crucial to follow specific steps to diagnose and resolve the problem efficiently.

Step 1: Check Your Faucets

  • Start simple. Verify all your faucets have proper flow. If the issue is isolated to one faucet, the problem may not be with your heater.
  • Ensure that the aerators on your faucets are clear of debris which can restrict flow.

Step 2: Inspect the Inlet Filter

  • Your heater’s inlet filter should be checked and cleaned regularly. Sediment build-up can cause significant flow rate decreases.
  • For detailed cleaning instructions, you can refer to the installation manual.

Step 3: Evaluate the Water Demand

  • Be mindful of the number of appliances or taps using hot water simultaneously. Overwhelming demand can reduce flow rates.
  • If needed, balance out usage to ensure your heater can keep up.

Step 4: Monitor Gas Pressure

  • Adequate gas pressure is necessary for optimal function. If pressure is too low, your unit may not be able to heat water quickly enough, affecting the flow rate.

Step 5: Consider Descaling

  • In areas with hard water, calcium build-up may occur in the heat exchanger. Descaling might be necessary to restore flow rate.
  • The Minnesota Tankless WH study suggests maintenance for efficiency.

By carefully following these steps, you should be able to identify the source of any flow rate problems with your Rheem Tankless Water Heater and take appropriate action to correct them. Remember, routine maintenance is key to preventing these issues before they start.

Diagnosing Water Temperature Issues

When troubleshooting your Rheem Tankless Water Heater, it’s important to focus on the specific problem you’re facing. Water temperature issues tend to fall under one of two categories: inconsistency with water temperatures or a case of overheating. Accurate diagnosis can lead to effective solutions.

Inconsistent Temperatures

If you’re experiencing inconsistent temperatures, it’s important to check the flow rates first. Your Rheem tankless heater has minimum flow rates that must be met to ensure stable temperature. Make sure that:

  • The water flow sensors are clean and unobstructed.
  • The in-line filter isn’t blocked, as it can restrict flow causing temperature fluctuations.

Sometimes, electronic components such as temperature sensors can malfunction. It’s advised to consult with the troubleshooting manual specific to your model for guidance on checking and replacing these parts.

Overheating Water

Concerning overheating water, it’s crucial to check the thermostat settings. Rheem tankless heaters have modulating temperature technology that should prevent too high temperatures. Here’s what you can do:

  • Verify the thermostat setting and adjust it down if necessary.
  • Inspect for any error codes that indicate a faulty thermostat which may need resetting or replacing.

If these steps do not fix the overheating issue, refer to the manufacturer’s guidance or contact a professional technician to avoid any risk associated with high-temperature water. Remember, routine maintenance can prevent many of these issues.

Electrical Connection and Power Supply

When troubleshooting your Rheem electric water heaters, checking the electrical connection and power supply is crucial. Firstly, ensure your unit is connected to the proper voltage. You might find the required voltage information in your installation manual, or you could refer to a professional.

Steps for Checking Electrical Connection:

  1. Turn off the power to your water heater at the breaker box.
  2. Check the power cord for any signs of damage. If you find any, it should be replaced.
  3. Verify that the plug is securely inserted into the power outlet.

For power supply issues, you may encounter certain indicators:

  • The unit does not power on.
  • Error codes are displayed relating to power or system performance.

Quick Checklist:

  • Power Source: Confirm that the circuit breaker hasn’t tripped.
  • Voltage: Match the unit’s requirement with your home’s supply.
  • Connection: Ensure all wires are properly connected and not corroded.

If your water heater continually trips the breaker, there may be an issue with the unit’s electrical components or a mismatch in the system’s electrical requirements. In this case, contacting a licensed electrician or a Rheem professional can help you resolve the problem safely.

Remember, electrical troubleshooting should be done with care. If you’re uncomfortable or unsure, always reach out for professional help.

Gas Supply and Combustion Analysis

When troubleshooting your Rheem tankless water heater, checking the gas supply and analyzing combustion are critical steps. Inadequate gas pressure or poor ventilation can lead to performance issues.

Checking Gas Pressure

  • Verify the Gas Type: Ensure your tankless water heater is connected to the correct gas type (natural gas or propane), as specified by the manufacturer.
  • Measure Gas Pressure: Using a manometer, measure the gas pressure at the unit’s gas supply line. The pressure should match the required rating indicated in your Rheem gas water heater specifications.

For accurate gas pressure readings, ensure all other gas appliances in your home are turned off during measurement.

Verifying Ventilation

  • Inspect the Vent System: Check for any obstructions or clogs in the venting pipes that could impede proper airflow.
  • Assess Vent Pipe Size: Confirm the vent pipe diameter is appropriate for your model, as incorrect sizing can affect combustion and performance.

Good ventilation is essential to avoid dangers such as carbon monoxide buildup. Proper vent maintenance helps ensure your unit operates efficiently and safely.

Remote Control Diagnostics

When troubleshooting your Rheem tankless water heater, the remote control is a great starting point. It can provide valuable diagnostic information about the state of your heater.

  • Error Codes: If your water heater has a problem, it often displays an error code on the remote control. Consult your Rheem manual for the meaning of specific codes.
  • Temperature Control: Check if the temperature settings are correct. Sometimes the temperature is set too high or too low, which can cause apparent malfunctions.
  • Control Board: Advanced diagnostic features may indicate a problem with the control board. If you suspect an issue, it’s advised to have a professional inspect the control board for any indication of a broken component.

To reset your heater’s system through the remote:

  1. Power off the water heater.
  2. Wait for a few moments, then power it back on.
  3. Use the remote to restart your heater.

Remember, always handle electrical components with care. If you’re not confident in your troubleshooting skills, contact a certified professional to assist you. Your safety is paramount.

Noise and Vibration Concerns

When dealing with your Rheem tankless water heater, it’s important to pay attention to unusual noise and vibration as they may indicate underlying issues needing attention. Here’s what you need to know:

Identify the Type of Noise:

  • Humming: A low-level sound typically associated with normal operation.
  • Rattling or Vibrating: Loose components or fluctuating water pressure can cause these sounds.
  • Whining or High-Pitched Noises: Often due to scale build-up or a restriction in the flow.

Troubleshooting Steps:

  1. Check for Loose Fixtures: Ensure all mounting screws and brackets are tightened.
  2. Inspect the Water Pressure: Both too high and too low pressure can lead to noise. Adjust the pressure within manufacturer-recommended levels.
  3. Examine Internal Components: Components like the fan or heat exchanger may occasionally become loose, leading to vibration.

Preventive Measures:

  • Regular Maintenance: Schedule routine check-ups to avoid sediment and scale accumulation.
  • Install a Pressure-Reducing Valve: If high water pressure is an issue.
  • Use Anti-Vibration Pads: These can help dampen noise if the unit is vibrating against its mounting surface.

Common Solutions:

  • Descale Your Water Heater: Scale can cause noise; descaling your unit can sometimes eliminate the problem.
  • Professional Help: If the noise persists, consult Rheem New Zealand Limited for advice or service.

A certain level of noise is to be expected with any tankless water heater, but if your Rheem unit starts making new or loud sounds, don’t ignore them. Identifying and addressing these concerns as early as possible helps maintain the efficiency and longevity of your water heater.

Professional vs. DIY Troubleshooting

When your Rheem tankless water heater is not functioning as expected, deciding whether to attempt a repair yourself or call a professional can be a tough choice. Here’s a breakdown of what you might consider in making your decision:

DIY Troubleshooting

  • Knowledge Base: If you have a basic understanding of how tankless water heaters work and are comfortable following troubleshooting guides, tackling common issues such as cleaning the in-line filter or resetting the unit could be within your ability. The reset button is typically located near the gas valve or electrical panel.
  • Cost Savings: For problems that don’t require technical expertise, DIY can save you the cost of a service call.
  • Time: If the solution is straightforward, you might be able to fix the issue quicker than waiting for a technician.

However, ensure you consult the manual or trusted online resources to avoid common pitfalls.

Professional Troubleshooting

  • Expertise: Complex issues, especially those related to gas or electrical components, should typically be handled by a certified technician to ensure safety and maintain your warranty.
  • Equipment: Professionals have the right tools and replacement parts on hand.
  • Warranty: DIY repairs may inadvertently void your warranty. Check your user agreement before beginning.

Remember, a professional technician will likely resolve the issue more efficiently and with less risk of error or injury. When in doubt, it’s always better to err on the side of caution and consult a professional.

Final Thoughts On Rheem Tankless Water Heater Troubleshooting

Troubleshooting your Rheem tankless water heater can often be straightforward and rewarding. Remember, identifying common issues like erratic temperatures or low flow rates can often be resolved with basic steps. Cleaning the inlet screen or checking for error codes can go a long way.

  • Error Codes: Look up what each code means in your manual or a trusted guide to tackle specific problems.
  • Regular Maintenance: Keep performance optimal by periodically descaling and checking venting systems.
  • Refer to Manuals: Manuals provide valuable information on routine maintenance and often contain a troubleshooting section.

Before reaching out to a professional, you save money and gain understanding about your water heater. Moreover, the feeling of fixing it yourself is quite satisfying! However, if issues persist or you encounter a problem beyond your skill set, do not hesitate to contact a technician. Safety should always be your priority.


  • Edmund Yeo

    🌱 I'm passionate about sustainable living and renewable energy, and I'm thrilled to share my journey towards a greener, brighter future with you. Join me as I explore the latest innovations, eco-friendly lifestyle tips, and inspiring stories from the forefront of the green energy revolution. Note: This website uses affiliate links which may earn a commission for purchases made at no additional cost to you.

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