Troubleshooting and Error Codes

This guide covers common issues and error codes for Mysa for Baseboards.

Error Codes

Mysa for Baseboards may display error codes on the thermostat screen. These codes indicate hardware issues that need attention.

H2 — No Heater Detected

Applies to: V2 and V1 only (Lite does not display H2)

What it means: Mysa did not detect a heater between the Load and L2/N connections.

Possible causes:

• Loose wire connection in a wire nut — as more wires go into a wire nut, connections can come loose
• Heater load wire not connected to Mysa Load
• Heater has malfunctioned
• Wiring error during installation

What to do:

1. Turn off power at the circuit breaker
2. Remove the thermostat faceplate
3. Check that all wires are properly secured in each wire nut — give each wire a gentle tug
4. Make sure heater wires connect between Mysa Load and L2/N
5. Reattach the faceplate and restore power

If the error clears, your thermostat is working correctly. If the error persists, contact support.

H4 — Relay Damaged

Applies to: V2 and Lite only

What it means: The internal relay was damaged, usually from a wiring error or exceeding the maximum load. This can appear days, weeks, or even months after installation.

What to do:

This error cannot be cleared — it indicates a hardware failure that requires thermostat replacement. Contact support immediately.

Warning Do not continue using a thermostat displaying H4. Turn off power at the breaker and contact support.

Other Error Codes

Other error codes indicate hardware defects that cannot be fixed by the user. If you see an error code not listed above, contact support with a photo of the error.

Common Issues

Thermostat Won't Power On

Possible causes:

• Power is off at the breaker
• L1 (line) supply wire not connected to Mysa L1
• Loose wire connection
• Thermostat not fully seated on base plate

What to do:

1. Check that the circuit breaker is on
2. Turn off power and remove the faceplate
3. Look for a green LED on the base plate — if lit, Mysa is receiving power
4. If no green LED, check that the L1 supply wire (usually black, from the breaker) is connected to Mysa L1
5. Check all wire connections are secure
6. Ensure the thermostat is clicked fully onto the base plate
7. Restore power

If the green LED is lit but the display doesn't work after reattaching the faceplate, contact support.

Heater Not Turning On

Possible causes:

• Thermostat is set to Off mode
• Setpoint is below current room temperature
• Heater type setting doesn't match your heater
• Wiring issue

What to do:

1. Check that the thermostat isn't set to Off — tap the mode icon to change
2. Raise the setpoint above the current room temperature
3. Verify the heater type setting matches your heater (Baseboard, Fan-forced, or Radiant)
4. If using Radiant mode, the heater only turns on when 0.5°C below setpoint

Heater Won't Turn Off

Possible causes:

• Heater wire connected to L1 instead of Load (common wiring mistake)
• Room temperature is below the setpoint
• Thermostat sensor issue

What to do:

1. Lower the setpoint below the current room temperature
2. Wait a few minutes — the heater may have a delay before shutting off
3. If the heater still won't turn off, turn off power at the breaker and check your wiring
4. Verify heater wires connect between Mysa Load and L2/N — not to L1. The L1 lead should only connect to the supply wire from the breaker.
5. If wiring is correct but the heater still won't turn off, contact support

Temperature Reading Seems Wrong

Possible causes:

• Thermostat is near a heat source (window, exterior wall, appliance)
• Thermostat was recently installed and needs time to stabilize
• Airflow around thermostat is blocked

What to do:

1. Wait 15–30 minutes after installation for the sensor to stabilize
2. Ensure the thermostat isn't in direct sunlight or near drafts
3. Compare the reading to another thermometer in the room

Note There is no way to manually calibrate the temperature sensor on any Mysa product.

Thermostat Won't Connect to Wi-Fi

Possible causes:

• Router is using 5 GHz only
• Wi-Fi password is incorrect
• Router is too far away
• Phone settings blocking the connection
• Router security settings incompatible

What to do:

1. Confirm your router broadcasts a 2.4 GHz network
2. Double-check your Wi-Fi password
3. Move closer to the router during setup
4. Restart your router if needed

Check phone settings:

• iOS: Enable Precise Location and Local Network Access for the Mysa app
• Android: Turn Location ON, turn Wi-Fi Assist/Smart Network Switch OFF

Check router settings:

• Use WPA2 or WPA2/WPA3 Transitional security (not WPA3 only)
• Disable MAC filtering or add the thermostat
• Disable band steering if your router auto-switches between 2.4 GHz and 5 GHz

Mesh or merged networks:

If your router merges 2.4 GHz and 5 GHz into one network name, try creating a temporary 2.4 GHz guest network for setup. After pairing succeeds, the thermostat will stay connected.

Thermostat Shows Offline in App

Possible causes:

• Wi-Fi network changed or went down
• Router was restarted
• Thermostat lost connection

What to do:

1. Check your home Wi-Fi is working
2. Soft reboot the thermostat (hold up + down for 10 seconds)
3. If still offline, re-pair the thermostat to Wi-Fi through the app

Reboot Methods

Soft reboot: Hold the up and down controls for 10 seconds. The thermostat will restart.

Hard reboot: Turn off the circuit breaker, wait 30 seconds, then turn it back on.

User Manuals

• Mysa for Baseboards - V2 User Manual (PDF)
• Mysa LITE for Baseboards User Manual (PDF)

Get Support

If troubleshooting doesn't resolve your issue, contact our team with:

• A photo of your thermostat display (showing any error code)
• A description of what's happening
• Your thermostat model (V2, Lite, or V1) — found in app under Settings > Thermostat Info

General support: support@getmysa.com

Installation issues: install@getmysa.com