ruud furnace troubleshooting

When dealing with a malfunctioning Ruud furnace, identifying and solving common issues can often restore your heating system without the need for a professional service call. In this article, we’re looking at some of the most frequent problems you might encounter, along with the common error codes of Ruud Furnaces.

Troubleshooting Common Issues with your Ruud Furnaces

Ensure Power Supply: Verify that the furnace’s power switch is on. Also, inspect your home’s circuit breaker or fuse box for a tripped breaker or blown fuse, and reset or replace it as necessary for better security of your furnace.

Examine the Igniter: Inspect the furnace’s igniter for any signs of damage or wear. If it appears intact, use a multimeter to test for electrical continuity. An absence of continuity for more than a few seconds indicates a need for replacement.

Adjust the Thermostat: Misalignment in thermostat settings can lead to frequent on/off cycles. If your thermostat includes a calibration scale, make the necessary adjustments. If issues persist, consider replacing the thermostat.

Assess Blower Motor Functionality: Check if the blower motor is receiving power. Replace the motor if it’s non-functional despite having power. If the motor operates but fails to circulate air, a snapped belt might be the issue. Replacing the belt should solve this problem.

Check Control Board: If the blower motor continuously receives voltage regardless of thermostat settings, the control board’s relay might be faulty. Replacing the control board should correct this problem.

Test Thermostat Continuity: A multimeter can help determine if the thermostat’s blower control contacts are sticking, leading to excessive airflow. Replace the thermostat if it fails this test.

Clean or Replace Flame Sensor: A soot-covered or defective flame sensor or light might inaccurately detect the presence of a flame, causing the gas furnace to shut off prematurely. Clean the sensor with an abrasive pad or replace it if cleaning doesn’t help.

Gas Valve Inspection: Ensure that the furnace’s gas valve is open. A non-operational valve, even when open, requires replacement.

Limit Switches Check: If the furnace overheats or fails to operate, the limit switch may be at fault. Test the switch with a multimeter and replace it if necessary. Also, verify that there is no blockage left which is restricting airflow.

Clean the Burners: Accumulation of debris or rust in the burners can hinder ignition. Safely clean the burners after ensuring the furnace is turned off.

Assess Gas Flow: If the burners don’t ignite despite an open and functional gas valve, the issue may relate to gas flow or pressure, often requiring a professional evaluation.

Ruud Furnace Error Codes

  • 0 – Standby: Indicates no faults and that the furnace is in normal standby mode.

  • C – Compressor on: This appears when the compressor is active, either in cooling or heat-pump mode.

  • H – Gas heat on: Indicates that the furnace is using gas to heat.

  • F – Continuous fan on: The blower fan is operating in a continuous cycle.

  • 10 – 1-hour lockout: This shows that the furnace is in a one-hour lockout after multiple ignition or flame detection failures.

  • 11 – Failed ignition: Detected when the furnace fails to ignite, which could be due to problems with the igniter or gas supply.

  • 12 – Low flame sense: The flame sensor is not detecting a strong enough flame, possibly requiring cleaning of the sensor or inspection of the burner.

  • 13 – Flame lost: Detected after the initial flame was lost, which could be due to issues with gas flow, the flame sensor, or the igniter.

  • 14 – Unexpected flame: A flame was detected unexpectedly, which could suggest a valve leakage or control issue.

  • 20 – Twinning fault: Indicates a problem with the connection or configuration of two furnace systems when they are twinned incorrectly.

  • 22 – Main limit open: Triggered by overheating, typically from restricted airflow or a malfunctioning blower.

  • 26 – Line and neutral reversed: As mentioned, this involves wiring errors needing correction.

  • 33 – MRLC (manual reset limit control) open: Known as a roll-out switch, this device opens to prevent overheating and requires a manual reset after addressing the overheating cause.

  • LED Codes:

    • Steady LED: This shows normal operation without any faults.

    • Single Flashing LED: This error indicates that the gas furnace failed to detect a flame three times, resulting in a one-hour system lockout. To remedy this, restart the system by shutting off the power for a brief period and then turning it back on. This reset may clear the error and initiate a new ignition sequence. If the problem continues, ensure that the gas supply, igniter, and flame sensor are functioning correctly.

    • Two Flashing LEDs: This code signals an issue with an open pressure switch or complications with the induced draft blower. Examine the pressure switch to see if it closes properly; if it doesn’t, it may need replacing. Additionally, check for any obstructions in the blower and vents that could affect airflow and air pressure.

    • Three Flashing LEDs: Indicates an open limit switch or triggered roll-out control. This could be due to restricted air vents or a loose blower wheel causing the system to overheat. Ensure that the air filter is clean and that the blower is in good working condition to resolve this issue.

    • Four Flashing LEDs: Occurs when the pressure switch is stuck closed or won’t open. Inspect the pressure tubing for blockages that might be causing the malfunction and clear them if found. If the issue persists, consider replacing the switch.

    • Six Flashing LEDs: This indicates that wiring is reversed between the line and neutral, which could lead to electrical problems within the furnace. This typically requires a professional to inspect and correct the control board and furnace wiring.

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Furnace Troubleshooting Guides

Our comprehensive troubleshooting guide offers step-by-step solutions to common issues. From heating failures to airflow problems, we've got you covered."

When should you connect with a professional?

While several things can be solved on your own, there are bigger and much more dangerous issues that call for a professional technician like those from Comfort Union. With their expert knowledge of every HVAC unit from different brands, they can take care of everything from repairs to installations to maintenance.

So, the next time you’re looking to get an HVAC system installed professionally, or getting it checked or cleaned, Comfort Union is the one to call! We continue to be a leader in the business because we understand all the issues that our customers face in detail and have set standards for all our services.

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