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Nest Offline

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Hi,  I am getting an error code E195. I have tried all that I can do technically. Not good at these things. All other devices in the home work so I know it is not WIFI. I even tried rebooting just by some small miracle it would help. Not!  I did a hard restart and saw the temperature for a minute but then went back to E195 error code.  What even made me check was the house got chilly so I went to check on my phone and it said offline. Went to look at thermostat and showed E195 no power to R wire detected. I did get new phone but that should not matter.  HELP!!


Community Specialist
Community Specialist

Hi vkarolyn13, 


Yikes! I'm sorry to hear that you're receiving an E195 code on your thermostat—this code means no power to the R wire detected. Here are a few steps you can take to troubleshoot this, and you may skip the steps you already took.


  1. Check if the breakers flipped on your breaker box. Check the circuit breaker or fuse box to confirm that the power supply to the HVAC system is functioning properly.
  2. If you used AC recently, check your system’s drip pan or drain tubes (skip this step if you only have a heating system).
  3. Ensure that the breaker associated with the HVAC system is not tripped or the fuse is not blown.
    • Turn off the main power to the HVAC system at the breaker box. The HVAC system can have multiple breakers, so make sure you turn them all off.
    • Check the furnace and fan, and make sure there are no lights that might indicate the system still has power. If there are still lights on the furnace or fan, the system might still have power, and you need to turn off the main power to your home at the breaker.
    • Search for the HVAC fuse. It’s usually on the furnace control board. Check your owner’s manual. Fuses can be different for each type of system. You might find a small U-shaped fuse with a number 3 label that is pink or purple-colored. You might also find a round fuse.
  4. Some utility companies install boxes that cut off the power during high-demand (peak) times. These energy savings boxes can cause an E195 code.
    • Search for an energy-saving box near the electric meter (possibly near their air conditioner).
    • Search for a small box with two lights on it (one light is red, the other is usually green). This box allows the utility company to cycle the customer’s air conditioner off and on during certain peak times of the day.
    • If you have an energy savings box:
      • Wait an hour or two for the rush hour to end, and then check if the code disappears.
      • If the code disappears, contact your utility company, landlord, and/or Homeowners Association (HOA) for details about the program and your home's participation in it.
    • If you don't have an energy savings box, proceed to the next step.
  5. Your HVAC system needs to have good airflow to work properly. A clog in the air filter can limit how much air flows over the cooling coils. If the clog persists, the cooling coils can freeze and cause your system to shut off.
    • Find your HVAC system’s air filter. The air filter is usually behind a grate in the hallway.
      • Check your walls and ceiling.
      • If you can’t find the air filter, search for it inside the furnace near the fan.
  6. Gather the power readouts of battery, VOC, VIN, and lIN from the thermostat under Settings > Technical Info > Power.
  7. If the power reading is VIN/VOC/IIN: N/A, or 0.01 or less, check the emergency switch.
    • The emergency switch isn’t the same as the breakers on the fuse box. It’s a breaker right next to the furnace or boiler and might be a light switch, breaker, or T switch. If anything went wrong electrically, like a power outage, this breaker probably switched off. Turn it off, then back on. If it’s a T switch, you need to unplug it, then plug it back in.
  8. Inspect the wiring for any potential damage, such as frayed or broken wires.
    • Make sure the thermostat wires are properly stripped and seated in the thermostat base.
      • Ensure that the R wire is securely connected to the corresponding terminal on the Nest Thermostat E and in the HVAC system. Make sure there are no loose or disconnected wires.
      • If there’s a common wire connected to the C terminal, ask the customer to remove it.
  9. Using a multimeter, you can test the voltage between the R wire and the C wire (if available) at the thermostat and HVAC system. This will help determine if there is a power supply issue or if the R wire itself is faulty.


Also, kindly send us a photo of your current Nest Thermostat E wiring configuration so we can take a closer look at the wires. 


Let us know how it goes.