Ruud U802VA050317MSA Error Code A044_F: Inducer Lo Pressure Switch Won't Open

What Does Code A044_F Mean?

Fault code A044_F on the Ruud U802VA is set when the Bluetooth Communicating IFC checks the low-stage inducer pressure switch before a heat cycle and finds it already closed while the inducer motor is not running. Before the board will light the burners, it uses the pressure switch as a safety interlock: with no inducer draft present, the switch contacts must be open. When they stay closed, the board can no longer trust the switch to prove that a real draft exists, so it refuses to advance the ignition sequence.

On this furnace the pressure switch senses negative pressure created by the inducer through a small rubber hose. If that hose is plugged with condensate, debris, or a spider web, trapped pressure can hold the diaphragm closed even with the inducer off. The switch itself can also fail mechanically with its contacts welded or stuck closed. Either way, the board sees a switch that never returns to its normal open resting state.

This is the opposite failure mode from the low-stage won't-close condition, which is set when the switch fails to CLOSE after the inducer starts and proves draft. A044_F is specifically a won't-OPEN (stuck-closed) fault detected with the inducer off. Because the pressure switch is a combustion safety device, the U802VA treats a switch that cannot open as a fault rather than a nuisance and blocks operation until the condition clears.

Ruud designed this proving logic so that a shorted or bypassed pressure switch cannot mask a genuine venting problem. That is why jumping the switch or ignoring the code is never acceptable — the interlock exists to keep the furnace from firing when a proper exhaust draft cannot be verified.

What You'll Notice

• The furnace does not light and the burners never come on, even though the thermostat is calling for heat
• The inducer may run only briefly or skip its normal pre-purge, because the board sees the switch in the wrong state before it begins
• No warm air is delivered and the home stays cold
• The contractor app or control reports the A044_F active fault for the low-stage pressure switch
• The problem persists across power cycles rather than clearing on its own

Common Causes

How This Is Diagnosed

A technician first confirms the switch state with the inducer off, checking continuity across the low-stage pressure switch terminals — a healthy switch reads open at rest. If it reads closed with no draft present, the switch or its wiring is suspect. The technician then inspects the sensing hose and port for blockage from condensate or debris, since a plugged hose can trap pressure and hold the diaphragm closed.

If the hose and port are clear but the switch still will not open with the inducer off, the pressure switch itself is confirmed failed and is replaced with the correct rating for this model. The technician verifies the new switch opens and closes at the proper set point and that the board proves draft normally through a full ignition cycle before returning the furnace to service.

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 A044_F code is present and the furnace will not begin its ignition sequence
• The pressure switch reads closed when the inducer is off, indicating a stuck switch or a blocked sensing hose
• The code returns immediately after a power cycle
• Condensate, corrosion, or debris is visible around the pressure switch port or its rubber hose

✓ Verified against manufacturer service manual — March 2026