What are some troubleshooting techniques for my Rheem tankless water heater?

What are some troubleshooting techniques for Rheem tankless water heater? Yes, it’s an essential matter to know clearly for its users. A user can follow some basic troubleshooting techniques to solve common issues immediately. Many people nowadays try to explain urgent matters by themselves. The user manual gave with the Rheem tankless water heater model also helps an individual to take action for small problems. People also seek help from professional plumbers, maintenance specialists, and experts according to the situation. They also contact the manufacturer if they find any severe issue. 

The troubleshooting allows finding common issues and indicates repair or replacement. The guide related to common water heater problems covers Rheem brand and some other. It used for gas and electric models of the brand.

The user should be aware of the potential dangers like burns from hot water or tank, electrical shocks from different connections, the risk of gas leakage, leaks of carbon monoxide from gas models and many other dangers. You should take troubleshooting steps carefully. It is better to take the steps you are knowledgeable about and comfortable with action. When you think the issue cannot be solved then in that case call a Rheem repair technician. They will smartly handle the issue. It is affordable to call for service. Therefore, you avoid serious injury because there is the technician to face the problem.

A most common type of troubleshooting techniques and solutions discussed below- 

What to do if there is no hot water?

Tripped circuit breaker shuts down gas or electric models which use the electricity. It hampers the flow of hot water into the faucet or shower.

Gas models

There may be an issue in the gas valve. You are required to check if the gas valve has been turned off. Your tank might be empty when the unit run by propane. You also need to check the pilot light mentioned in the manual guide if it has been lit or not.

Electric models

Electric models of Rheem water heaters come with two coils. Having no hot water from the unit is impossible. The user should check the circuit. Sometimes the circuit in the electrical box gets tipped. When you notice the unit is on, there is a high possibility that the circuit breaker in the box has failed to start the process.

When there is not enough hot water

If there is not enough hot water, then it is because you have just moved to a new home or you are not familiar with the capability of the water heater or your water heater is new. The unit is also undersized for a reason. You are using the hot water more quickly. That issue is more familiar with electric models. They heat water less quick than gas models.

Gas water heater

The burner is working. It is firing effectively, but enough hot water is not coming out. The reasons are-

  • The unit is smaller than required in the home.
  • The gas valve plugged with debris for a long time.
  • The user sets the temperature as too low.

Electric water heater

When you find the problem is new. Then be sure the two heating elements or thermostats are not working correctly. You have to replace it with a new one. It cannot provide enough hot water when the unit finds two heating elements or thermostat is terrible for continuing the heating process. 

A build-up mineral deposits in the tank

Hard water is harmful to the tank. It builds up mineral deposits in a tank very quickly. The tank is required o e drained periodically. Otherwise, within three to five years mineral build up will reduce the capacity by up to 15 gallons.

Water leakage and​​​​ water on the floor

Necessary tools required to make troubleshooting

There are list of some items given below; it will assist the user to do basic troubleshooting immediately. Let us provide a thorough look at the tools-

Instruction manual- In the manual, there is a section defined as Rheem water heater troubleshooting. It addresses the different types of problems and gives an immediate solution. If you lost the manual, then you will get the guide online. You need to search the model name and number to find it. You also can contact the manufacturer.

  • Flathead and Philips screwdrivers
  • Electrical Tester.
  • Pipe tape: you have to make sure it is for water and not for gas.
  • Small plumber’s wrench.
  • Bucket and towels.
  • BBQ-style lighter.
  • Heating element wrench (electric models only): element wrench s purchased in online home improvement stores. 

Rheem Water Heater Troubleshooting

Let us follow a few tips to solve Rheem water heater problems. You can also call a Rheem service company to do any repair according to their Raheem Troubleshooting Guide.

How to fix if there is no hot water?

Electric and gas water heaters run by electricity

Troubleshoot the issue by analyzing the lack of power to the unit.

  • When you find the water from the tap is cold, you give a gas unit 15 minutes and pressure relief valve 30 minutes for making enough hot water. Then you check the water from the tap. Therefore, if the water remains cold then that case there is a problem in the heating process of the unit.
  • The circuit breaker in the electrical panel is to be turned ON. If you find it is midway between the two, it has n tripped. Again you turn all the way to OFF and then turn it ON into position. When you notice the circuit continues to trip. If there's an electrical issue arise. It should be diagnosed immediately by a qualified professional. You have to repair by a service technician. 

Gas type water heaters

When you find the unit uses a pilot light, and if it's not lit, you have to follow some instructions. The instructions found in the user manual. You have to relight the pilot using BBQ lighter. Again if the unit uses electronic ignition and there is no fire. In that case, the timer needs to e replaced for doing the heating process. Gas may leak if the unit not appropriately handled during replacements. To do the work effectively, you call a repair technician.

How to troubleshoot when there is not enough hot water

Gas water heater

You have to adjust the thermostat to a higher setting if you find your gas water heater is not delivering enough hot water. A flat screwdriver needed to e placed in the slot on the adjuster. There is detail information about the issue in a manual guide.


The thermostat should not be higher than 120 degrees Fahrenheit. It will reduce the risk of severe burns from scalding.
If you notice the unit is still not making enough hot water, the reasons may be the unit is undersized according to your requirement or needs, filled with mineral sediment or plugged with a gas valve. Rheem technicians easily identify many issues. They will check the valves and clean it. If the gas valve needs replacement, the technician will also do it.

Electric water heater

The temperature is toe adjusted to 120F. If you realize the water is warm but not hot or the heating process is prolonged. In this case, you can be sure that one of the heating elements and a thermostat is in bad condition.

  • An electrical tester is used to test the heating elements and thermostats. We know electric current cannot pass from a sad part. In the online WebPages, parts like Rheem element and Rheem thermostats are available. You can also use titanium elements for replacement. Titanium elements are durable, and it is available in the stores.

Replacements of the thermostat and other elements

How to replace a component or thermostat are described below-

  • The circuit needs to be turned off in the electrical panel. You turn off a double 240V circuit from the electrical panel of the water heater.
  • To replace the heating element you just shut off the water that leads to the water heater. You turn off the pump's circuit if you have well and pump. Hot water from the faucet must e opened till the water stops to flow. So it takes out the pressure off the water tank.
  • The user should remove the part if it is in package form.
  • The wrench should also be removed carefully from the package during heating element is replaced.
  • The screwdriver is used to disconnect the wires. Most wires reconnected with bad elements and thermostat. So the user needs to cautious while disconnecting the cables.
  • A couple of towels is to e placed on the floor during the replacement of the element. By using the wrench at first, you quickly loosen the part by your hand. Pull the sad part out. Then insert the new feature and tight it carefully by your side. A wrench also needed to tight the portion & the aspect will show no leaks. You should never over tighten the element.
  • During the replacement of the thermostat, you take a picture of the wiring of the thermostat. The image is to decide before removing the wires and dangerous part. New thermostat gets installed. After installing you will check the picture to see all the cables are connected securely.

Special reminder

The user prefers to have no leakage at all in their unit. In this case, drain the tank first by using a garden hose to the threaded spigot. The spigot should take near the bottom of the tank. You can also run the tube to a floor drain or outside of the home and turn on the spigot.

How to troubleshoot if there is water on the floor?

If the water problem starts immediately after installation or repair then, in this case, a fitting is probably loose. You have to check all the pipe connections before that turn off the power of the unit. Wet connections are to e tightened smoothly. Pipe tape is used to tight the connections. When you do any replacement of an electric element, you have to remove the cover. At last check, the item as it must be tight gently if necessary.

What to do if everything set?

After you realize all the connections are correctly installed and tightened. The next step is to determine the relief valve. You should analyze the relief valve if it is releasing the water.

  • You can place the bucket on the floor beneath the valve or hand the bucket if it is light. In this way, the next time water leaks you have found the source of leakage.
  • When the thermostat is set too high, it will cause water to force out from the valve. So turn the temperature lower or down if its set above 120 Fahrenheit.

How to take action if water is still dripping?

You can do replacements if the water continues to trickle from the unit. It also flows from the temperature and pressure relief valve. Let us follow the steps below-

  • Right valve must match with the model. You should purchase the right valve according to the model of the unit. In the manual, there are lists of parts. You also find the parts online. Most common elements are Rheem T&P valves. The cost is cheap.
  • You need to turn off the power and water to the unit. In case if you use the great pump is also required to turn it off.
  • You can either run hot water from the tap for few minutes or attach a hose to drain — the process taken near the bottom of the tank. As a result, the water level goes down to below the location of the valve.
  • The user also opens the relief valve by flipping it. It will take out the remaining pressure off the tank.
  • The wrench is used and turn left/counterclockwise to loosen the old valve.
    •Wrap the pipe tape in a clockwise manner around the new valve thread. Tight by using hand until snug. In this way, you can install it.
  • The wrench is to be tightened by one-quarter to one-half of each turn.
  • Again you need to turn on the power and water back to the unit. It will allow heating the water. Generally, the valve leaks because it is not tight. Leakage happens when the valve is too loose. So, you can tight it from another quarter to half a turn.

The tank is leaking after you find the water is not coming out from a fitting or the T&P relief valve. It is the signal to change the old water heater into a new one.


In this Rheem water heater, several safety tips given. It will prevent any burn and shocks. Some additional warnings about the water heater re given below- 

  • The users have to evacuate the home when they find any smell of gas near the gas water heater. They should turn off the gas valve. They should also ignite anything in the house. Immediately call a repair technician and gas company.
  • People should also install a CO detector near a gas water heater. Carbon monoxide (CO) is the byproduct. It is very deadly. In this situation, the sensor will help to prevent damage. On the other hand, if the carbon monoxide detector shuts down immediately evacuate the place. At last, you call 911 or service technician as an emergency.


Do not solve the issue if the steps not mentioned in the article. A service technician will help to solve the problems. They need to evaluate the whole situation whether to repair or replace the water heater. The replacement is acceptable if the unit is more than seven years old. Repair of the group in most cases is expensive.

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