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Error code reference

Rheem Water Heater Error Code 99

Faulty blower motor.

Rheem codesRheem water heater codes

Faulty blower motor.

First step from the service manual

Contact a dealer or qualified service technician.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What 99 means on a Rheem water heater

Error code 99 on a Rheem water heater indicates a faulty blower motor condition. The blower motor is a critical component in power-vent and hybrid heat pump water heaters, responsible for moving combustion air or managing airflow through the heat exchange system. When the control board detects that the blower motor is not operating within expected parameters, such as failing to reach proper speed, drawing incorrect current, or not responding to control signals, it triggers this fault code and shuts down the unit to prevent unsafe operation.

The most common causes of this fault include a seized or worn blower motor, wiring harness failures between the control board and the motor, and motor capacitor failures that prevent proper startup. In some cases, the motor may be receiving power but failing to spin due to a mechanical obstruction or bearing failure. The control board monitors blower motor feedback signals, and any disruption in that communication loop can trigger the code even if the motor itself is partially functional.

Because diagnosing a blower motor fault accurately requires testing motor windings, verifying supply voltage at the motor terminals, checking capacitor integrity, and inspecting the wiring harness, this repair is best handled by a qualified technician. Improper handling of the blower circuit or control board connections can cause additional damage or create safety hazards. Rheem specifically directs owners encountering this code to contact a dealer or qualified service technician rather than attempt self-repair.

Source: manufacturer service documentation.

Common causes of 99

  1. 01

    Failed or seized blower motor

    Part replacement

    The motor may have worn bearings, burnt windings, or a seized rotor that prevents it from spinning. This is the most direct cause of the fault and typically requires motor replacement.

  2. 02

    Wiring harness damage or loose connections

    Wiring / connection

    Corroded, damaged, or disconnected wiring between the control board and the blower motor can interrupt the signal or power supply, causing the control board to log a blower fault even if the motor is otherwise intact.

  3. 03

    Faulty motor capacitor

    Part replacement

    Many blower motors rely on a start or run capacitor to achieve proper torque and speed. A failed capacitor can prevent the motor from starting or cause it to run at incorrect speeds, triggering the fault code.

  4. 04

    Obstruction in the blower assembly

    Wiring / connection

    Debris, dust buildup, or a foreign object lodged in the blower wheel can physically prevent the motor from reaching the correct RPM, causing the control board to detect an out-of-range condition.

  5. 05

    Defective control board

    Part replacement

    If the control board is failing, it may incorrectly report a blower motor fault even when the motor is functioning properly. This is less common but should be considered after the motor and wiring have been ruled out.

See the test procedure for each cause

Frequently asked questions about 99

What does 99 mean on a Rheem water heater?
Error code 99 on a Rheem water heater indicates a faulty blower motor condition. The control board has detected that the blower motor is not operating correctly and has shut the unit down as a safety measure. This fault requires diagnosis by a qualified service technician, as it involves electrical and mechanical components within the blower system.
Can I fix error code 99 on my Rheem water heater myself?
Rheem directs owners to contact a dealer or qualified service technician for this fault code rather than attempting self-repair. Diagnosing a blower motor fault requires testing motor windings, supply voltage, capacitor integrity, and control board signals, which are tasks that call for proper tools and training. Attempting repairs without the appropriate knowledge can cause further damage or create a safety risk.
Is it safe to use my Rheem water heater when error code 99 is displayed?
No, the water heater has shut itself down when displaying code 99 and will not operate normally. This is a protective response to prevent unsafe operation due to the blower motor fault. You should leave the unit off and contact a technician before attempting to use the heater again.
Will resetting my Rheem water heater clear error code 99?
A manual reset may temporarily clear the fault display, but if the underlying blower motor problem has not been repaired, the code will return once the unit attempts to operate again. Resetting without addressing the root cause does not fix the fault and could delay necessary repairs. A technician should inspect the blower motor and associated components before the unit is returned to service.
How much does it cost to repair error code 99 on a Rheem water heater?
Repair costs for a blower motor fault vary depending on the specific cause and your location. A simple wiring repair or obstruction clearing will be less expensive than a full blower motor or control board replacement. Parts and labor costs combined can range from around $150 to $600 or more depending on the component needed and local service rates.

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