Ruud U802VA050317MSA Error Code T117_F: Detect RPM Motor Failure
What Does Code T117_F Mean?
Fault code T117_F on the Ruud U802VA is a transient RPM motor failure — the Bluetooth Communicating IFC detected that the blower motor could not hold its commanded speed at some point during operation. The variable-speed ECM blower continuously reports its actual RPM back to the board, and when that feedback diverges from the target the board logs the event. The T (transient) prefix means it happened intermittently rather than as a constant condition, so the furnace may still be operating for now.
On this model the blower is an ECM (electronically commutated motor) with an integrated electronic control module. That module regulates speed and can degrade before it fails outright, producing occasional RPM deviations that show up as this transient code. Mechanical load also matters: worn motor bearings, or a blower wheel loaded with dust and debris, force the motor to work harder to hold speed and can cause it to fall short momentarily.
T117_F is the early, intermittent stage of the same problem that becomes the active RPM failure when the motor can no longer maintain speed at all. It is not a lockout and does not by itself stop the furnace, but the U802VA logs it so a technician can catch a developing motor problem through the fault history in the contractor app before it turns into a persistent fault or a dead blower.
Because the diagnosis and any repair involve testing and replacing the ECM motor or its control module, this is professional work rather than a homeowner fix — but noticing the code early can prevent a mid-winter no-heat failure.
What You'll Notice
- The blower occasionally surges, slows, or ramps oddly instead of holding a steady speed
- Airflow from the registers feels inconsistent during some heat cycles
- You may hear the blower motor change pitch or hunt for speed at times
- The furnace otherwise appears to run, since the fault is intermittent rather than a shutdown
- The contractor app fault history shows the T117_F transient RPM fault
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Blower motor speed instability | Most common | ✗ Call a pro → |
How This Is Diagnosed
A technician reviews the fault history in the Bluetooth contractor app to see how often T117_F is occurring and under what conditions, then watches live RPM data during a heat cycle to see whether the motor is falling short of its commanded speed. They check the mechanical side first — inspecting the blower wheel for dirt buildup and checking the motor bearings for wear or drag that would load the motor.
If the mechanical load is normal but the motor still cannot hold speed cleanly, attention turns to the ECM motor and its integrated control module. The technician tests the motor and module separately with the appropriate tools to determine which is degrading, since a transient RPM fault often precedes an outright failure of one of these components.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- The T117_F fault appears in the app, even if the furnace still runs, so the motor can be inspected before it fails outright
- Airflow or blower speed is noticeably inconsistent during heat cycles
- The blower makes surging or speed-hunting noises
- The transient fault is becoming more frequent, suggesting the ECM motor or module is progressively failing
Frequently Asked Questions
Can I keep using my Ruud U802VA with a T117_F code?
It may keep running because this is a transient fault rather than a lockout, but you should not ignore it. It is often an early sign the ECM blower motor or module is degrading, and getting it inspected can prevent a complete blower failure later.
What is the difference between T117_F and A117_F?
T117_F is the intermittent version — the motor occasionally could not hold speed — while A117_F is the active version where the motor persistently cannot maintain its target RPM. T117_F often shows up first as an early warning before the problem becomes constant.
Could a dirty blower cause this?
Yes. A blower wheel caked with dust adds unbalanced load that can make the ECM motor struggle to hold speed. A technician will check the wheel and bearings as part of diagnosing an RPM fault, though the fix here is professional work rather than a homeowner task.
✓ Verified against manufacturer service manual — March 2026