Rheem furnace 2 blinks: Pressure switch did not close within 10 seconds
The inducer started but the pressure switch did not close within ten seconds. The inducer keeps running and waits, so the furnace sits there blowing without ever lighting.
Applies to: Rheem, Ruud and Weather King *RC 92+ full size upflow and *RL 90+ full size downflow condensing furnaces, per installation instructions 708503a.
What it means
After the control energises the inducer it expects the pressure switch to close, proving the inducer is genuinely moving air and the vent is clear. Rheem's instructions give a specific window: if the switch does not close after ten seconds the fault LED blinks twice repetitively, and the inducer continues to run until the switch closes. That last detail explains what a homeowner actually sees, which is an inducer that runs indefinitely with no ignition and no lockout. The furnace is not stuck; it is waiting, indefinitely, for a signal that is not coming. This is the one blink count that means the same thing on both Rheem code lists.
Most common causes
- A blocked vent or intake termination outside — snow, ice, a nest, or a cap left in place. This is the most common cause in cold weather.
- Water in the pressure switch hose or in the condensate trap.
- A blocked condensate drain backing water into the collector box.
- A cracked, kinked or disconnected pressure switch hose.
- An inducer spinning but not developing enough suction, often from worn bearings or a dirty wheel.
- A failed pressure switch.
How to diagnose it
- Look at the vent and intake terminations outside for anything blocking them. This is homeowner work and it resolves a large share of these.
- Note whether the inducer sounds normal, weak, or noisy — a failing inducer often sounds different before it fails outright.
- Note whether there is standing water near the furnace, which points at a blocked condensate path.
- Note that this code behaves the same way on Rheem's standard furnaces, so the model check matters less here than on the other counts.
How to fix it
- Clear the vent or intake termination if it is blocked.
- Everything inside the cabinet — hoses, collector box, condensate trap, inducer, switch — is technician work.
- Do not jumper the pressure switch to force the furnace to fire. That interlock is what stops the furnace burning gas when the flue is not clear.
Notes
Two blinks is the only count where Rheem's standard list and the condensing furnace instructions agree. Both describe a pressure switch that will not close.
Related
- 3 blinks — Pressure switch closed when it should be open
- Which blink code list applies — Rheem publishes two blink code lists that contradict each other
All codes for this manufacturer
Rheem, Ruud and Weather King furnace blink codes — every code, with what differs between models.
Not sure this is your brand?
The same count means something else on other furnaces. What 2 flashes means on every brand puts them side by side.