Ruud U802VA050317MSA Error Code A117_F: Detect RPM Motor Failure
What Does Code A117_F Mean?
Fault code A117_F on the Ruud U802VA is an active RPM motor failure — the Bluetooth Communicating IFC has determined that the blower motor cannot maintain its commanded speed as an ongoing condition. The variable-speed ECM blower reports its actual RPM back to the board continuously, and when that feedback persistently falls short of the target the board sets the active fault. The A (active) prefix distinguishes this from the transient version, which is only an occasional, self-recovering deviation.
On this model the blower is an ECM (electronically commutated motor) whose speed is regulated by an integrated electronic control module. When RPM control fails persistently, the module is the most common point of failure, though the motor windings can also fail. Either way, the furnace can no longer deliver the airflow it was designed for.
Inadequate blower speed has real consequences on the U802VA: heating output drops, efficiency falls, and reduced airflow across the heat exchanger allows heat to build up. That can cause the main high-temperature limit to open, which on this board can escalate into the overheat and dead-blower codes if the airflow deficit is severe enough. A117_F is therefore both a performance fault and a condition that can trigger safety shutdowns.
A117_F is the persistent counterpart to the transient RPM fault: where the transient code is an early, occasional warning, the active code indicates the motor has reached the point of continuous failure. Diagnosis and repair require testing and replacing the ECM motor or its module and are professional work, not a homeowner fix.
What You'll Notice
- Weak or reduced airflow from the supply registers even when the furnace is running
- The blower runs at the wrong speed — noticeably too slow or unable to ramp up correctly
- The furnace may short-cycle or trip on high-temperature limit because airflow is inadequate
- Rooms heat slowly or unevenly, and the furnace struggles to reach setpoint
- The contractor app reports the A117_F active RPM motor failure
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Failed blower motor or ECM module | Most common | ✗ Call a pro → |
How This Is Diagnosed
A technician confirms the persistent nature of the fault by watching live RPM data during a heat cycle — the motor commanded to a target speed but consistently unable to reach or hold it. They rule out mechanical load first, checking the blower wheel for heavy debris and the bearings for wear or drag that would keep the motor from reaching speed.
With mechanical causes excluded, the focus is the ECM motor and its integrated control module. The technician tests each separately with the appropriate tools to determine whether the winding or the module has failed, then replaces the correct component for this model. After the repair they verify the blower reaches all commanded speeds and confirm the main limit no longer trips from inadequate airflow.
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 A117_F code is present and airflow is weak or the blower runs at the wrong speed
- The furnace short-cycles or trips on high-temperature limit because the blower cannot move enough air
- The blower cannot ramp up to its normal speeds during a heat call
- The rooms are heating slowly or unevenly due to reduced airflow
Frequently Asked Questions
Is A117_F the same as a dead blower on my Ruud U802VA?
Not quite. A117_F means the blower runs but cannot hold the correct speed, whereas the separate dead-blower fault means the motor could not run at all and the furnace hard-locks out. A117_F can, however, lead to overheating and further faults if the airflow shortfall is severe.
What is the difference between A117_F and T117_F?
A117_F is the active, persistent RPM failure — the motor consistently cannot maintain speed — while T117_F is the intermittent early warning. Seeing A117_F usually means the ECM motor or its module has reached the point of needing replacement.
How much does the repair cost?
It depends on whether the ECM control module alone or the whole variable-speed motor needs replacement, and labor rates vary by region. These are among the pricier furnace parts, so ask your technician for a local estimate once they identify the failed component.
✓ Verified against manufacturer service manual — March 2026