Rheem · Furnace / HVAC
4 blinks Pressure switch closed (stuck)
What this code means
The opposite of the 2-blink fault — the pressure switch is reading closed when it should be open before the inducer starts.
Most likely causes
- Stuck or miswired pressure switch
- Failed inducer motor relay
What to try first
Not typically a homeowner fix; needs the switch tested with the inducer off.
Safety note: if this code returns after one clean reset, stop resetting it — repeated lockouts usually mean a real fault that needs a licensed technician. Never bypass a safety switch.
FAQ
What does Rheem error code 4 blinks mean?
Pressure switch closed (stuck). The opposite of the 2-blink fault — the pressure switch is reading closed when it should be open before the inducer starts.
Can I fix Rheem code 4 blinks myself?
Usually not. Not typically a homeowner fix; needs the switch tested with the inducer off. If the code returns after one reset, it needs a licensed technician.
What causes Rheem code 4 blinks?
The most common causes are: stuck or miswired pressure switch; failed inducer motor relay.
Other Rheem furnace codes
All Rheem furnace error codes →
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This information may contain errors or not apply to your exact model — always double-check it against your appliance's own manual before acting. If there's any chance of a gas, fire, electrical, carbon monoxide, or other safety hazard, stop and call a licensed professional or the appropriate agency (e.g. your gas utility) instead of relying on this page alone.