Rheem Tankless Water Heater Code 61 [Why+ How To Fix]

Rheem tankless water heater code 61 is the error indication of the combustion fan failure of abnormal blower speed. The blower motor fails to turn freely when it gets clogged with dirt and debris. 

Also, the insufficient voltage supply to the blower or loose wiring harness to the PCB Molex connectors leads to this error. Besides, the defective blower motor or PCB is the culprit itself.

rheem tankless water heater code 61

Anyway, while troubleshooting, inspect the fan motor and remove the obstruction. Then check all the connectors between the fan and PCB to make sure that they are secured enough.

Measure the resistance of the motor winding to ensure it is receiving enough voltage. If the blower motor windings are within specifications, replace the bad PC board.

What Is Error Code 61 On Rheem Tankless Water Heater?

As already mentioned, error 61 on Rheem tankless water heater is a clear sign of combustion issues due to a faulty blower motor. Basically, if it is a gas-operated water heater, it is quite needed for proper combustion to continue the ignition process of the system. 

Rheem tankless water heater

 A draft blower motor, located near the burner chamber plays a big role in this process. During the heating cycle, it stays on and draws combustion air into the system, making sure that the gas is burning efficiently. Plus, it vents out the combustion gases so that the heat distributes evenly throughout the inside of the heat exchanger.

In fact, due to several electrical issues, the fan fails & creates restrictions in the combustion. And when the PC Board senses the imperfect combustion, it throws the diagnostic error 61 in the display. 

Rheem Tankless Water Heater Code 61 [3 Easy Solutions]

Thoroughly read out all the responsive factors for the error code 61 on Rheem tankless water heater with the easiest and well-effective solutions.

Note: You can read our guide on why Rheem tankless water heater code 76 and how to fix it.

1. Obstructed Blower Motor

When it is the term about malfunctioning of the blower motor, higher chances are it is not spinning freely. This mainly happens due to the collecting of dirt particles or soot around the fan shaft.

obstructed rheem tankless water heater blower motor

Foreign materials and debris crawl into the vent pipe and end up in the fan assembly, creating restrictions to running the fan.  

To be clear saying, a failing blower fails to receive the voltage single from the control board and essentially you will find error 61 on the display.

So, the first obvious fix here is to inspect the blower and remove the obstruction. Wondering how to do it? Follow the below sections:

How To Fix:

To fix a stuck fan motor, follow these steps:

Step #1: Power Down Your Water Heater

As for the first step, disconnect your water heater from the electrical connection. Also, turn off the power supply from the remote controller or at the circuit breaker. 

power down your water heater

Also, turn the gas shut-off valve clockwise to the “OFF” position. 

Step #2: Remove The Access Panel To Your Heater

Unscrew all the screws from the front of your water heater. Disconnect the cover panel and set it aside. 

remove the access panel to your heater

Step #3: Locate The Blower Assembly

Now, locate the two screws from the bottom that is holding the bracket of the computer. Simply unscrew them as you can see in the picture using a Phillips screwdriver to take off the control board.

locate the rheem tankless water heater blower assembly

When done, remove the wires from the way of the blower motor, PCB, flame rod wire connectors, and so on.

Step #4: Inspect The Blower

In this step, remove the two screws from the top of the computer board to inspect the blower. Now tilt down the cover and you will see the blower inside just like shown in the picture.

remove the two screws from the computer board

Then, remove the three small screws around the blower shaft that holds the housing. When done, simply pull out the fan from the cabinet.

Step #5: Clean The Blower

You will find the small blower motor in the middle. Try to give it a spin using your hand to check whether it is moving freely. Ensure the fan blade is tight on the motor shaft. 

clean the rheem tankless water heater blower

Remove the stuck debris from the blower. If needed, use a lightly damp rag for better cleaning. 

Don’t miss cleaning the breather box. For this instance, you can use a vacuum cleaner to vacuum out the debris.

2. Faulty Blower Motor Wiring

In most cases, you will find the blower motor spins freely but if it is not turning on during the ignition sequence, then it’s likely an electrical or power issue. The higher possibility is that it isn’t getting sufficient power from the heater’s control board. 

Rheem tankless water heater faulty blower motor wiring

This would be the faulty wiring harness to the blower assembly. So in this step, you have to test this component electrically.

How To Fix:

Follow these steps to figure out if your blower is getting power:

First off, inspect the wiring harness to the motor for damaged and loose connections. Fix the loose connections. Ensure the connectors between the blower motor and control board are secured and tight. 

Then take a multimeter and set it to the voltage setting. Now locate the blower Molex connections at the PCB. It will be the upper left side of the control board, where you will see red, black, yellow, blue, and white wires connected for outdoor models as shown below.

blower Molex connections at the PCB

Attach the voltage meter leads to the connector G between the Blue and White wires. It should give a reading of 120 to 160 VDC.  If the reading is in this range, the control board is working properly. 

Then, you need to find out if there is any pulse output from the fan motor. Set the voltage meter to read between 4 to 10 VDC for indoor models. Attach the leads to the connector G between the Blue and Yellow wires for the outdoor models.

It’s time to activate the fan by pressing this button. Locate the “MAX” (SW2) Button on the upper right side of the PCB. Just press and hold the button like in the picture below and the blower will turn on. 

locate the “MAX” (SW2) button on the upper right side of the PCB.

Take the pulse reading. In case you are not getting the correct pulse and voltage, be sure the fan assembly is defective and you need to replace it. 

3. Defective PCB

If there are any major malfunctions in the PCB, it fails to send the correct voltage to the blower motor to continue its operation. The printed circuit board works as the brain of the tankless unit and due to glitches or faults, it fails to communicate with the entire system.

rheem tankless water heater defective PCB

In such cases, only replacing the faulty PCB will resolve the issue. The replacement procedures of PCB are quite straight forward and you can do it by yourself. Just make sure that you are replacing the correct PCB model for your tankless water heater. 

How To Replace PCB On The Rheem Tankless Water Heater

Follow the below few phases to replace the bad PCB on your tankless unit:

Phase #1: Start by turning off the power supply to your water heater. Unplug the unit from the power outlet on the wall. Also, turn the gas shut-off valve to stop the gas supply to the unit.

Phase #2: Remove the top two screws from the top and bottom of the front cover. Take the front cover off.

Phase #3: Now locate the PCB from the inside housing. Disconnect all the wires and connectors from the PCB. 

disconnect all the wires and connectors from the PCB

Before that, you can take a picture of the connections and thus you can precisely replace them while installing the new PCB.

Phase #4: Remove the two retaining screws at the top right and bottom left side of the PCB. Also, disconnect the multi-pin connectors from the assembly.

Phase #5: When done, gently lift up the PCB and pull it out of the chassis. Install the new PCB back in position. Reconnect all the wires and connectors. Ensure snug connections of all the wiring. 

 install the new PCB back in position

Don’t take this hassle if you are technically inclined. We recommend heading to a professional to complete the replacement task for you. 


How much combustion air does a tankless water heater need?

Sufficient combustion air is quite essential for the ignition in the tankless water heater. As a general rule, a standard water heater needs up to 50 cubic feet of air per 1,000 BTUs/hr to ensure proper combustion. 

Do all tankless water heaters need to be vented?

No! All tankless water heater doesn’t need to be vented. If it is gas operated, proper venting is quite needed to blow hot exhaust gas outside. But the electric tankless water heaters do not need ventilation. 

How can I regulate the temperature of a tankless water heater?

Almost all tankless water heater has a LED panel that offers users to control the temperature of the system. You can easily regulate and set your desired temperate up or down using the arrows on the right side of the LED screen. 

In Closing!

When the blower motor of the system isn’t operating as it should, the PC board senses this change and shows the error code 61. 

However, the problem can easily be resolved by ensuring a few well-effective troubleshooting processes like cleaning the blower motor shaft, fixing the loose connection, or replacing the damaged one. When you find a major malfunction in the resistance, you need to replace the fan. 

Well! That’s all from us here. After thoroughly reading our comprehensive guide, there should be no confusion left over on Rheem tankless water heater code 61 and you can resolve it by yourself. Do let’s know through comments if you need any further assistance. We are always here for you!!

“You can also read our guide on how to fix Rheem tankless water heater code 99“.

About William

William is the founder of Fireplacehubs.com. 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.

Leave a Comment