How to Read Rheem Furnace Error Codes and How to Fix it
Written by Mas Broto
This Rheem error codes guide is made for the person who might want to try and fix their furnace. I wanted to list the Rheem furnace error codes with some guidance on what the possible underlying issues could be to make these errors appear.
Rheem furnaces are designed with an advanced 7-segment diagnostic display. They don’t use flashing LED light sequences to indicate errors, like other brands. Rheem and York give you a simple error code that you can use for diagnostics of your furnace problems.
Rheem Furnace Error Codes
There have been many times I have seen furnace error present itself, but the cause of this error is not necessarily what it shows. I will try and give you the best possible diagnosis and a description of what you can do to fix the error.
Here, we will list the meaning of specific Rheem furnace error codes.
Rheem Furnace Normal Operation Codes
Y1 on (Legacy Mode Only)
Y2 or Any Communicating Cooling Call
Gas heat – No “V” Signal (Legacy Mode Only
Calibration – No “V Signal (Legacy Mode Only
cd or Cd
Dehumidification active (Legacy Mode Only)
Rheem Furnace Shared Data Error
No Shared Data
Memor Card Invalid
Blower Horsepower Conflic
Blower Manufacturer Conflict
Old Shared Data
Rheem Furnace Flame Sense Signal Error Codes
One Hour Lockout
Low Flame Sense
Rheem Furnace Limit Control Error Codes
Main Limit Open
Heat Assist Limit (HALC) Open
Manual Reset Limt (MRLC) Open
Rheem Furnace Pressure Switch Error Codes
Low Pressure Switch Closed – Inducer OFF
Low Pressure Switch Open – Inducer on High
Low Pressure Switch Open – Inducer on Low
High Pressure Switch Closed – Inducer OFF
High Pressure Switch Open
Rheem Furnace Blower Error Codes
Blower Fault – Blower Remains Running
Blower Fault – Blower Not Running
Blower Overspeed Fault
No Communications with Blower Motor
Rheem Furnace Gas Valve Error Codes
No Communications with Gas Valve
Gas Valve Servo Fault
Another Misc. Error Codes
Line and Neutral Reversed
Supply Air Temp / Sensor Fault
Internal Fault / Control Fault
Common Problems and Possible Solution
This chapter summarizes the most common problems you could encounter with your Rheem furnace. If you are unable to diagnose and solve the problem with the information below, contact an experienced and certified HVAC technician for certain complex problems.
Flame Sensor Problem
If the flame sensor is dirty, clean the sensor. If faulty or broken, replace the flame sensor. Click Here for the detailed guide to clean/replace furnace flame sensor.
Try resetting your furnace’s circuit breaker. Click Here for the detailed guide tp reset your furnace.
Check the furnace igniter for cracks, if it is then replace the igniter. If it isn’t cracked, use a multimeter to test for continuity. Click Here for the detailed guide to check the furnace igniter.
Check the blower motor. If it isn’t running, the motor has likely broken. If the motor runs but air doesn’t move, the connecting belt may the problem. Click Here for the detailed blower motor troubleshooting guide.
Check the furnace control board. Click Here for the detailed guide to troubleshooting funace control board.
Many modern furnaces have an LED light that will either be flashing or just showing some codes. Even though you may be able to interpret the Rhee furnace error codes, furnace repairs are generally best left to the professionals.
Have been in the heating and air conditioning (HVAC) industry for over 20 years. He is person that will grow and thrive to learn more about the HVAC industry throughout his career. Mas Broto is also a blogger, who's dedicated to bringing you the best knowledge to get ahead in the game of life.