TROUBLESHOOTING

Red LED

 

 

 

 

 

 

 

 

Flash

Error/Condition

Comments/Troubleshooting

 

 

 

 

1

External lockout (exceeded retries)

Failure to sense flame is often caused by carbon deposits on

 

 

the flame sensor, a disconnected or shorted flame sensor lead

 

 

or a poorly grounded furnace. Carbon deposits can be cleaned

 

 

with emery cloth. Verify sensor is not contacting the burner

 

 

and is located in a good position to sense flame. Check sensor

 

 

lead for shorting and verify furnace is grounded properly. Verify

 

 

gas supply to valve, gas valve in "On" position and appliance

 

 

lighting properly. Verify flame reaches flame sensor during

 

 

ignition attempts and gas pressures are correct.

 

 

 

 

2

Pressure switch stuck closed

Pressure switch stuck closed. Check switch function, verify

 

 

inducer is turning off. Refer to wiring diagram, terminals PSI /

 

 

PSO.

 

 

 

 

3

Pressure switch stuck open

Check pressure switch function and tubing. Verify inducer is

 

 

turning on and pulling sufficient vacuum to engage switch.

 

 

Refer to wiring diagram, terminals PSI / PSO.

 

 

 

 

4

Open high temperature limit switch

Verify continuity through limit switch circuit. Refer to wiring

 

 

diagram terminals, HLI / HLO.

 

 

 

 

5

Flame sensed with gas valve de-energized

Verify the gas valve is operating and shutting down properly.

 

 

Flame in burner assembly should extinguish promptly at the

 

 

end of the cycle. Check orifices and gas pressure.

 

 

 

 

6

Open rollout switch

Verify continuity through rollout switch circuit. Refer to wiring

 

 

diagram terminals, RO IN / RO OUT.

 

 

 

 

7

Low flame sense current

Low flame sense current is often caused by carbon deposits on

 

 

the flame sensor, a poorly grounded furnace or a mis-aligned

 

 

flame sense probe. Carbon deposits can be cleaned with

 

 

emery cloth. Check or improve furnace and module ground.

 

 

Verify sensor is located in or very near flame as specified

 

 

by the appliance manufacturer. Refer to wiring diagram FS

 

 

terminal and GND.

 

 

 

 

8

Ignitor relay fault

This flash code does not indicate a broken, disconnected or

 

 

shorted ignitor. It indicates the ignitor relay contacts on the

 

 

ignition module are not functioning properly. Replace the

 

 

ignition module.

 

 

 

 

Rapid Flash

Reversed polarity

Verify the control and furnace are properly grounded. Check

 

 

and reverse polarity (primary or secondary) if incorrect.

 

 

 

 

Continuous

Normal operation

No fault

On

 

 

 

 

 

 

 

Off

Control failure

Verify power to the control, replace control if power is at the

 

 

control and no lit Red LED

 

 

 

 

White-Rodgers is a division of Emerson Electric Co.

The Emerson logo is a trademark and service mark of8 Emerson Electric Co.

www.white-rodgers.com www.emersonclimate.com

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White Rodgers 50M56U-843 installation instructions Red LED Flash Error/Condition Comments/Troubleshooting
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50M56U-843 specifications

The White Rodgers 50M56U-843 is a versatile and reliable universal thermostat known for its innovative features and user-friendly design. This device is particularly popular among homeowners looking to optimize their HVAC systems for improved comfort and energy efficiency.

One of the standout features of the 50M56U-843 is its compatibility with a wide range of heating and cooling systems. This includes conventional and heat pump systems, making it an excellent choice for various types of home environments. The thermostat supports both single-stage and multi-stage systems, allowing for comprehensive climate control tailored to specific needs.

The 50M56U-843 boasts an easy-to-read backlit display that provides clear visibility in low-light conditions. This user-friendly interface makes programming and setting adjustments straightforward, ensuring that users can quickly and easily modify settings for maximum comfort. The thermostat's simple navigation menu allows users to adjust temperatures, set schedules, and switch between heating and cooling modes with ease.

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In terms of technological advancements, the 50M56U-843 incorporates features such as auto changeover, which allows the thermostat to automatically switch between heating and cooling modes as needed. This ensures optimal comfort without the need for constant manual adjustments. The unit also supports a wide temperature range, accommodating various climate conditions.

Another notable characteristic is its easy installation process. The 50M56U-843 is designed with user-friendliness in mind, providing clear instructions for mounting and wiring. This makes it feasible for homeowners to install the thermostat themselves without requiring professional assistance.

In summary, the White Rodgers 50M56U-843 is a dependable and efficient thermostat that combines functionality with user convenience. Its versatility, energy-saving features, and easy installation make it an ideal choice for those looking to enhance their home’s heating and cooling efficiency, while ensuring a comfortable living environment year-round.
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