What does Ruud code 45 mean?
Ruud furnace code 45 means the low-pressure switch is open when the control expects it to be closed on the supported control family. Confirm the model number and diagnostic chart inside the furnace door before replacing parts.
What causes Ruud code 45?
- A blocked intake or exhaust vent
- A restricted condensate drain or pressure hose
- A weak inducer motor or pressure switch
Can I troubleshoot Ruud code 45?
- With the furnace off, check outdoor intake and exhaust openings for snow, ice, leaves, or nests.
- Replace a visibly dirty air filter, restore power once, and note whether the code returns.
How much does Ruud code 45 cost to fix?
A pressure switch replacement typically costs between $175 and $900 nationally.
When should I call a technician?
Call a technician if the vent is clear and the pressure-switch code returns; combustion-air testing requires instruments.
Sources and model scope
Fault codes vary by model and control board. Confirm the diagnostic chart inside your furnace panel or the official manual before acting.
Scope used here: Rheem/Ruud RGFG-family controls using the documented two-digit diagnostic table.
- Rheem Manufacturing Company: RGFG Series Gas Furnace Installation Instructions and Diagnostic Codes
92-24161-104-06 · Rheem/Ruud RGFG-family furnace controls; confirm the unit model and its door chart before applying a code meaning.
Compiled by Warmlo Editorial · Reviewed August 2026
This is general information, not professional advice. Gas, electrical, and combustion repairs can be dangerous — when in doubt, call a licensed technician.