ecobee says "Calibrating"
ecobee groups a "calibrating" message with power loss: the thermostat has no internal power source and runs on power from your heating and cooling equipment. Once is not a concern. If it keeps happening during heating or cooling calls, ecobee points to equipment safety switches or the transformer, which is work for a licensed HVAC technician.
What does "Calibrating" on an ecobee mean?
ecobee's support article on reboots is written for a thermostat that frequently loses power or is displaying a "calibrating" message. It treats the two as the same problem. The article explains that the ecobee thermostat has no internal power source. It is powered by your heating and cooling equipment, and if that equipment has no power, the ecobee will not power on.
So the message is a sign that the thermostat has just started up again. ecobee's current article does not give the exact screen wording or say how long the message stays, so we do not either.
It has nothing to do with the Temperature Correction setting, which some people call calibration. That setting only changes when you change it; see how to calibrate an ecobee.
Is one "Calibrating" message a problem?
Usually not. A single restart after a power outage, after work on the system, or after the thermostat was taken off the wall is expected. If the thermostat comes back, shows the right temperature and starts heating or cooling when it should, you can move on.
Some restarts are easy to explain. A storm that briefly cut power to the house, or a technician switching the system off for service, both restart the thermostat. A repeated message with no outage behind it is different. ecobee says interruptions to the power supply can make the thermostat go black or reboot during heating or cooling calls. A pattern tells you where to look.
How do you tell what is causing the restarts?
Use the runtime reports in ecobee's System Monitor. ecobee says losses of power usually appear as gaps in the data, and the readings around each gap are a clue:
| Restart during | Just before the gap | When data returns | Causes ecobee names |
|---|---|---|---|
| Cooling | Usually a request for cooling | Inside temperature generally lower | A float switch or condensate pump cutting power when water backs up |
| Heating with a furnace | Usually a request for heating | Inside temperature generally higher | Furnace safety equipment, such as a high-limit switch, shutting off after overheating |
| Heating with a boiler or zone valves | Usually a request for heating | Inside temperature generally higher | A transformer without enough capacity for the thermostats and zone valves |
If the gaps line up with heating or cooling calls, write down the dates and times. That record saves a licensed HVAC technician time.
What can you do from the thermostat?
Not much changes the cause, because the cause is in the equipment's power, not in a setting. What you can do:
- Watch whether the message appears with heating, with cooling, or at random.
- Check System Monitor for gaps and note them.
- Avoid large jumps in the setpoint in very cold weather. ecobee lists long run times among the reasons a furnace overheats, and suggests lower heat setpoints and a schedule without large temperature increases during colder periods.
- If cooling or heat does not start right after the thermostat comes back, give it a few minutes. ecobee thermostats have a Compressor Min Cycle Off Time threshold that keeps the compressor off between cycles; how that delay works is on compressor protection.
ecobee links overheating to reduced airflow, including clogged air filters, and to cooling-side shutoffs from blocked condensate drains. Both are equipment maintenance. The float switch, high-limit switch and transformer are all parts of the heating and cooling equipment, so have a licensed HVAC technician look at them.
Has it happened more than once in the last few days?
- Yes
Do the gaps in System Monitor follow a call for heating or cooling?
- Yes
The equipment is likely cutting power during those calls. Note the times and call a licensed HVAC technician.
- No
Note when it happens and whether the whole home lost power. Mention the pattern to a licensed HVAC technician if it continues.
- Yes
- No
A single restart is expected after a power interruption. If the temperature and modes look right afterwards, nothing else is needed.
If the reading looks wrong after the thermostat comes back, that is a separate question, covered on ecobee temperature different from the room. For other ecobee messages, see the ecobee hub.
Frequently asked questions
- Is the "Calibrating" message the same as calibrating the temperature?
- No. The message appears on its own after the thermostat loses and regains power. Adjusting the temperature reading is a separate setting called Temperature Correction, which you change by hand on the Thresholds screen.
- How long does the "Calibrating" message last?
- ecobee's current support article does not give a duration. If the message clears and the thermostat goes back to normal, there is nothing more to do. If it keeps coming back, track when it happens.
- Why does my ecobee keep restarting when the heat comes on?
- ecobee says power loss during heating calls often comes from safety equipment in the furnace shutting off power when it overheats, or, on boilers and zone valve systems, from a transformer that cannot supply enough power. Both are for a licensed HVAC technician to diagnose.
- Can I see when my ecobee lost power?
- Yes. ecobee says power losses usually show as gaps in the runtime reports in its System Monitor. A gap right after a call for heating or cooling points to the equipment cutting power during that call.