Error code reference

Aprilaire Furnace Error Code 2 Flashes

Pressure switch stuck closed - the control senses the pressure switch is closed when the vent blower is off.

SourceAprilaire Hvac - Service Manual - RA661001: 1870p. 34

Diagnostic procedure

The full 2 Flashes procedure

Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.

MyPros+ · DiagnosticsStep 1 preview

First diagnostic step

Check for faulty pressure switch or wiring.

SourceAprilaire Hvac - Service Manual - RA661001: 1870p. 34

Unlock with pass

More steps, wiring diagram references, and verified part numbers

Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.

Unlock 2 Flashes procedure $9.95

Or subscribe: $29/month for all codes plus Max diagnostics, with 70 Max messages a day. Plus applicable tax.

Where this code is documented

1 manual in the MyPros+ library documents this code for Aprilaire furnace.

Models covered by the manuals that document this code

75,000+ service documents · 20,000+ error codes · 100+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass · Plus applicable tax

The full 2 Flashes procedure

Where this code is documented

Models covered by the manuals that document this code

Related Aprilaire furnace error codes