Rheem R802VA07542117MSA Error Code T087_F: Power Board Temp Sensor Fault

What Does Code T087_F Mean?

The Bluetooth Communicating IFC (Integrated Furnace Control) in your two-stage, variable-speed R802VA07542117MSA carries a small temperature sensor on the board itself so it can watch its own operating temperature. That self-monitoring is a protective feature: it lets the control notice when its electronics are running hotter than they should, for example in a poorly ventilated furnace closet. Code T087_F is logged when that onboard sensor reads outside the valid range, which means the board has lost the ability to watch its own temperature.

Because this is a monitoring function rather than a combustion-safety device, the furnace does not lock out and Rheem rates T087_F as low severity. In practice the furnace may keep running normally. The catch is that the sensor is integrated into the control board rather than being a separate plug-in part, so unlike the other sensor codes on this furnace it usually cannot be fixed by swapping a thermistor. If the reading cannot be recovered, the board itself is what needs to be evaluated and possibly replaced.

T087_F stands apart from the other sensor faults on this board. The air-temperature sensors (T081_F return, T082_F supply, T084_F outdoor) watch the airstream, and the EXV superheat sensors (T085_F suction line temperature, T086_F suction pressure, T088_F EXV measurement) watch the cooling refrigerant. T087_F is the only one of the group that watches the control board's own internal temperature. All of them are low-severity monitoring faults and none is a hard lockout.

One thing worth noting: because the sensor reports board temperature, an out-of-range reading can occasionally mean the board actually got too hot at some point, not just that the sensor drifted. That makes furnace-room ventilation worth checking alongside the board itself.

What You'll Notice

• The alphanumeric display shows "T087_F", or the LED blinks the code one digit at a time with a roughly three-second pause between digits
• The furnace often continues to run and produce heat
• The fault stays logged in the Bluetooth contractor app even after a power cycle
• No lockout occurs and the thermostat is still answered
• In some cases the furnace or its closet feels unusually warm around the control area

Common Causes

How This Is Diagnosed

Because the sensor is integrated into the control board, a technician cannot simply measure and swap a plug-in thermistor as with the other sensor codes. Instead the technician reads the reported board temperature through the Bluetooth contractor app, compares it against the actual ambient conditions, and looks for signs the board has overheated, such as discoloration, a burnt odor, or heat-stressed components.

The furnace's installation and ventilation are checked, since a genuinely hot board points to an environmental cause rather than a bad sensor. If the reading is invalid and the environment is normal, the control board is the failed part. This is informational only; control-board work is not homeowner-safe.

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 code stays active and you want the board's self-monitoring restored
• The control board shows any discoloration, a burnt smell, or other signs of heat damage
• The furnace closet or cabinet runs hot or has poor ventilation around the control
• The fault persists after a power cycle, indicating the onboard sensor is not recovering on its own

✓ Verified against manufacturer service manual — March 2026