Ruud U802VA050317MSA Error Code *T057_F: Inducer Hi Pressure Switch Won't Close (Two-Stage Only)
What Does Code *T057_F Mean?
The Ruud U802VA is a two-stage furnace, and it uses a separate high-stage inducer pressure switch dedicated to high-fire operation. This switch is set to close only when the inducer is spinning fast enough to establish the stronger exhaust draft that high fire requires — because at high fire the burners consume more gas and produce more flue gas, they need more draft to vent safely. T057_F is logged when the inducer runs up to high speed but that high-stage switch does not close, so the Bluetooth Communicating IFC cannot confirm adequate high-fire draft. The 'T' prefix marks this as a transient (intermittent) condition, and this code exists only on two-stage models.
The telltale of T057_F is that low fire can still work while high fire fails. The low-stage pressure switch has a lower draft threshold, so a partial vent restriction can leave enough draft for low-stage operation to prove and light, yet fall short of the stronger draft the high-stage switch demands. The furnace may heat fine on mild days when it stays in low stage, then throw T057_F on colder days when the control calls for high fire and the high-stage switch cannot close.
Within this board's high-stage pressure family, T057_F is the 'won't close at high fire' failure. Its counterpart is T055_F / A055_F, 'Inducer Hi Pressure Switch Won't Open,' where the same high-stage switch fails in the opposite direction — staying closed when it should be open. Because the U802VA is an 80% furnace venting exhaust outdoors, the most common homeowner-safe cause of T057_F is a partial blockage at the outside vent terminal that trims draft just below the high-stage requirement. Deeper causes — a high-stage switch that is drifting out of calibration, or an inducer not reaching full high speed — are internal and require a technician.
What You'll Notice
- The furnace heats on low fire, especially in milder weather, but struggles or fails to deliver full heat on the coldest days.
- You notice the house cannot quite keep up when a strong, high-output cycle should be running.
- The inducer ramps up to high speed, but the burners do not step up to high fire (or drop back after trying).
- The contractor app logs T057_F, sometimes intermittently and tied to high-demand cycles.
- Outside, the vent terminal shows a partial obstruction — a rim of snow or ice, leaves, or a partial nest — that still leaves the pipe mostly open.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Blocked vent or insufficient draft at high stage | Most common | ✓ DIY fix → |
How This Is Diagnosed
Because low fire working and high fire failing points at a draft margin, diagnosis starts at the outdoor vent terminal, checking for a partial restriction that would clip high-stage draft while still allowing low stage. If the terminal is clear and T057_F still appears on high-fire calls, the technician measures whether the inducer reaches full high speed and tests the high-stage pressure switch and its hose for calibration drift, cracks, or condensate. Those internal checks are not homeowner tasks.
How to Fix It: Clear the outside vent and intake terminal of partial obstructions
What You'll Need
Steps
- Shut off power and gas first Turn off power to the Ruud U802VA at the breaker or the furnace switch, and shut off the gas supply valve at the furnace. If you smell gas, leave immediately and call your gas company. Do not continue until both power and gas are off.
- Inspect the outdoor vent/intake termination closely Go outside and examine where the furnace vent (and intake, if present) terminates. Because T057_F is a high-stage draft shortfall, look for PARTIAL obstructions — a rim of ice, drifting snow, matted leaves, or a partial nest — that leave the pipe mostly open but trim the draft margin high fire needs.
- Gently clear the terminal and its surroundings Remove the snow, ice, leaves, or nesting material from the terminal and the area right around it using a soft brush or a gloved hand. Do not push anything into the pipe or use force that could crack it, and make sure snow or roof runoff is not repeatedly drifting back over the opening.
- Restore gas and power and force a high-fire cycle if you can Turn gas back on, restore power, and call for heat. If possible, set the thermostat well above room temperature so the furnace is driven toward high fire, and confirm it steps up and stays lit without logging T057_F.
When to Call a Professional
Contact a licensed HVAC technician if:
- T057_F still appears on high-fire calls after the outdoor vent and intake terminal are confirmed fully clear.
- The furnace runs only on low heat and will not step up to high fire even in cold weather.
- The inducer sounds like it is not reaching full high speed, or you suspect it is weak.
- You suspect the high-stage pressure switch or its hose is at fault — do not attempt to test, adjust, or replace the switch or hose yourself.
Frequently Asked Questions
Why does my Ruud U802VA heat fine sometimes but throw T057_F on the coldest days?
On mild days the furnace often stays in low stage, whose pressure switch needs less draft. On cold days it calls for high fire, and the high-stage pressure switch needs stronger draft to close. A partial vent restriction can allow low fire but starve high fire, which is exactly what T057_F reports.
Does T057_F apply to single-stage furnaces?
No. T057_F is a two-stage-only code. It refers specifically to the high-stage inducer pressure switch, which single-stage models do not have. The U802VA is a two-stage, variable-speed furnace, so it uses this high-stage proving check.
What is the difference between T057_F and T055_F on this furnace?
Both involve the same high-stage pressure switch. T057_F is 'won't close' — the switch fails to close when the inducer runs at high speed, so high-fire draft can't be proven. T055_F is 'won't open' — the switch stays closed when it should be open. They are opposite failures of the same high-stage switch.
✓ Verified against manufacturer service manual — March 2026