How To fix nest e73 error and what are the Causes of nest e73 error fix

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Key Takeaways

  • The Nest E73 error indicates a problem with the Rc wire, typically causing a loss of power to the thermostat.
  • Common causes of the E73 error include overworking the HVAC system, blown fuses, clogged drain tubes, and power supply disruptions.
  • To fix the Nest E73 error, check the wiring, inspect the HVAC fuse, and ensure proper functioning of the drain tubes and drip pan.
  • Troubleshooting steps may involve turning off breakers, examining fuses, and assessing the condition of various components.
  • If troubleshooting does not resolve the E73 error, contact customer service for further assistance in diagnosing and fixing the issue.

Nest e73 error fix the problem on your Nest Thermostat is necessary before you can use it again. It’s possible that your Nest Thermostat isn’t detecting your Rc wire electrically, which would result in an E73 error. The problem can be fixed by inspecting the drain tubes, drain pans, the HVAC system’s wiring, AC breaker, air filter, and air conditioner. Nest’s intelligence lies primarily in its auto-away mode, which allows it to maintain a comfortable environment in your absence by learning your routines and adjusting the Thermostat accordingly. It’s more sensitive to its surroundings and has some exciting features. Here you can get all information about the nest e73 error fix.

Nest e73 error fix:

The nest e73 thermostat frequently displays the error code e73 / no power to RC cable detected when the AC outdoor unit/compressor unexpectedly turns off. Overheating of the compressor, clogged filters, running out of gas, problems with the outdoor fan motor, or even issues with the compressor itself are potential causes of the outdoor unit’s shutdown. Having the air conditioner’s exterior unit serviced usually fixes the problem. Customers should contact their maintenance service or the HomeIQ support line for assistance.

Causes of Nest e73 error fix:

The Nest e73 error can occur for several reasons, including the Rc wire not receiving power. Most of them, however, are reversible and so simple to repair. Overworking your system, which could damage its air conditioning unit, is the most prevalent reason for such an issue. The Nest e73 error can be triggered by the following:

  • Overworking the Nest in hot weather can cause the air conditioner to fail.
  • The power supply to your system could be disrupted by the blown fuse, leading to a sudden and unexpected shutdown of your Nest.
  • Drip pan water can lead to a wide variety of issues. Nest error e73 is the most typical example of this.
  • An apparent cause of this error is a power supply disruption brought on by a drop in voltage on the Rc line.
  • This flaw in e73 has been manifested in numerous ways, including clogged drain tubes.

Ways to nest e73 error fix:

1: Look at the wiring.

Step 1: Using the circuit breaker, disable the air conditioner, heater, and humidifier. Since your HVAC system probably has more than one circuit breaker, you should always ensure that all of them are off.

Step 2: Your Thermostat’s display can be disconnected from its base by pulling the Rc wire out, leaving the other cables intact. By doing so, it will enter a heat-only mode.

Step 3: Take out your RC wire and examine it to ensure it’s straight and has at least 1 cm of exposed copper.

Step 4: Ensure there is nothing on the wire to impede its movement, including rust or paint.

Step 5: Verify the Rc wire’s voltage with a voltmeter to ensure it stays stable.

Step 6: Since most air conditioners break down in the middle of the summer if your Nest thermostat is showing a voltage of 24 volts, the fault is with your AC unit

Step 7: Reinsert the wire into the Nest connector and hold down the connector button.

Step 8: All the wires should go through this procedure to be sure.

Step 9: In order to turn on the electricity, you must flip the breaker.

Step 10: Reconnect your Nest thermostat to its base and press the on button.

2: Check HVAC fuse:

Even with clean filters, summer heat might cause the HVAC system’s fuse to blow. Therefore, the HVAC system’s ability to send electricity to your Thermostat will be impeded.

1: The first step is to turn off the breaker that provides electricity to the HVAC system.

2: There may be many circuit breakers in your system; flip them all off.

3: Next, look for telltale signs that the system is active, such as the fans, furnace, and lights.

4: Look at the HVAC fuse on the control board.

5: There are various types of fuses, so it’s best to consult the handbook for your specific device to determine which type to use.

6: Now that you’ve inspected the fuse, ensure it still works. It’s damaged and has to be replaced if it’s lost colour or turned black.

7: If it’s broken, replace it and put back the panels you took out.

8: The last step is to activate the circuit breakers and restore power.

Verify the spouts and catch basins:

Condensation from your air conditioner or heat pump will leak into the drip pan and eventually make its way outside. If the water cannot drain properly because of a clogged drain tube or drip pan, your air conditioner or heat pump will turn off to prevent damage. The E73 error occurs when the HVAC unit suddenly stops supplying electricity to the Thermostat. Try these troubleshooting methods to see if they help you fix the problem.

1: Turn off the breaker to the HVAC system. You should check to see that all of the circuit breakers in your system are off before continuing.

2: If the lights on your fan or heater continue to glow, it could mean that there is still power in your system.

3: Find the drip pan by tracking down the cooling coils. Sometimes, the cooling coils atop your furnace may take the shape of a pyramid.

4: If you need help locating it, try looking for additional details online or in the manual provided by the manufacturer.

5: Do not try to unseal your cooling system by removing panels that include sealants or metal tape if the coils behind them are sealed.

6: The drip pan is often located under the cooling coils with one or more drain tubes leading to it. Ensure the drip pan is dry and the drain tube is not plugged.

7: Sometimes, the drip pan is attached to the base or a wall of the heater.

8: Locate the plastic tubing on the side of your furnace that leads water from the air conditioner to the exterior or a drain.

9: A safety valve in the air conditioner’s drain tube, also called a drain/float switch, is connected to the furnace by a small wire.

10: Take apart the toggle and examine the drain pipe for moisture.

11: The presence of water suggests the potential for a blockage. Rust is an early symptom of water damage and should be watched for.

12: For advice on unclogging a drip line, you can consult the user manual for your HVAC system or ask about a related topic in an online forum.

Get in touch with the service crew:

If you’ve tried the troubleshooting mentioned above steps and are still needing help, please feel free to contact customer service for further assistance. They will provide you with the highest quality assistance available. Describe what you’ve done to try to fix the issue thus far. They’ll have a better grasp of the situation after reading this. Because of this, you can more quickly and effectively eliminate the problem.


To nest e73 error fix, check the HVAC fuse, filters, Rc and general wiring, and drain tubes on your Nest thermostat. Verifying that the AC breaker is on in the electrical panel is one of the most straightforward troubleshooting steps you can do. Other checks, like those of your drip pan and drain tubes, maybe more involved and call for the assistance of a professional.


What does the Nest E73 error mean?

Getting an error like E73 indicates wiring issues with your Nest. Because of this, the Thermostat will stop receiving power and eventually break.

What Does the Nest E73 Code Indicate?

When the Nest Thermostat does not successfully electrically identify the red cooling wire (also known as the Rc wire), an E73 error signal will appear.


  • Sehrish Kiran

    With years of experience in research and writing, I have honed my skills to provide valuable insights and captivating content. My journey through different fields and topics has equipped me with a well-rounded perspective that enriches my articles. Protection Status