Error code H2Updated a year ago
What to do if Mysa shows an H2 Error Code
An H2 error occurs when there is an open heating circuit, preventing Mysa from detecting a heater load. In most cases, this suggests that the wires connecting your Mysa to your heater may be either loose or incorrectly connected.
Electricity flows into your Mysa, which then receives and regulates the electrical load. Mysa sends commands to your heater to initiate or cease operation. If these commands successfully reach the heater, the electricity is transformed into heat.
Now, when the H2 error code appears on your Mysa's display, it indicates that your Mysa is indeed receiving power from your home's wiring—otherwise, it wouldn't turn on. However, the error signals that Mysa is attempting to send electricity to the heater, yet the heater circuit is unresponsive. Essentially, in electrical terms, Mysa is not detecting a heater load. This discrepancy likely stems from an issue with the wiring between Mysa and your heater.
Rebooting Mysa
It is important to try to clear the error by rebooting the Mysa. Some errors are very rare and may only be seen once. In these cases, it is not necessary to perform any additional actions.
For Mysa for Baseboard Heaters, this can be done by
Removing the faceplate on your Mysa. Follow the steps below:
Unscrew the faceplate - there’s a small screw at the bottom of your Mysa.
Carefully slide off the faceplate.
Keep it unattached for 5-10 minutes.
Carefully reattach the faceplate. Be careful not to bend the pins that connect it to the base of your Mysa!
Your Mysa will take a few seconds to reboot.
- Flipping the breaker controlling your Mysa OFF, waiting around 30 seconds, and flipping it back ON.
Warning! High Voltage!!
Any work with high voltage equipment can be dangerous or even fatal if you do not take proper precautions. You should never work with live wires.
Heater Circuit Troubleshooting
Did you follow our Installation and Compatibility Guide?
If you did, here’s a quick refresher:
L1 = Power supply from breaker
L2 = Neutral (120V) / Second phase leg (240V)
Load = Heater Load
To complete the heater circuit:
Please make sure Mysa’s load connection is making contact with the heater supply connection.
Mysa’s L2 (N) wire is making contact with the heater return wire.
Another possibility is that the heater’s return wire in the L2 or neutral bundles is not making secure contact with the other wires in the wire nut. If you need help determining your specific wiring configuration, click here to visit the guide.
Everything looks fine, the wires are all matched properly. What’s next?
Your wiring connection may simply be loose! Ensure that your breaker is OFF and go back to your Mysa’s wiring. Here are some common issues we see:
The wire nuts are not applied correctly. Wire Nuts aren’t just a “cap” for the wires! They’re a tool to make sure the wires twist together securely for a secure connection. Make sure that you are using them to perform the actual connection and not just placing them on top; wire nuts must be tight and secure without leaving exposed wire.
You disrupted the connection when placing your Mysa back into the gangbox. Before you secure your Mysa to the wall and turn your breaker ON, make sure you carefully place the wired connections back in the gangbox. Hastily or forcefully pushing them in may cause an otherwise ideal wiring connection to become loose. This could happen immediately or gradually if H2 displays after your Mysa has been functioning properly for a period of time.
There’s too much (or too little) exposed wire. Is one of your wires mostly exposed copper? Or is the exposed part of the wire much shorter than expected? Make sure that the length of exposed wire is similar in length to the exposed wire that comes with the Mysa. Use a wire stripping tool if necessary. When applying the Wire Nuts, make sure there isn’t any bare wire exposed.
Still having issues? Consider the following:
Your Home’s Wiring
Did you make any changes to your home’s electrical wiring system, or is this part of a new home installation?
If yes, try swapping the L1 and the Load as shown in the diagram, or consult with a certified electrician if you are not confident that the heater itself is wired correctly.
Warning! High Voltage!!
Any work with high voltage equipment can be dangerous or even fatal if you do not take proper precautions. You should never work with live wires.
2. A Problem With Your Heater
Did you buy Mysa to replace a thermostat that stopped working?
If yes, it may have actually been the heater that malfunctioned - not the original thermostat.
3. Is it a commonly used heater in your home? Are you confident it was working before you installed your Mysa? If the answer is no, you may want to check with an electrician that the heater is actually still functional. While electric heaters usually have a long lifespan, they can fail.
3. Electrical Specifications
Did you correctly check Mysa’s electrical specifications before installing your Mysa?
Mysa’s electrical requirements are very specific but should cover the vast majority of residential electric heating installations. While Mysa devices are safety certified, we do not recommend you exceed an amperage of 16A or a wattage of 3800W. Doing so may cause the H2 error to appear, although it is uncommon.
Was a relay used or installed in this thermostats location?
In some instances, a relay may be used to artificially reduce the overall load of the heaters connected to a single thermostat. This is most common when multiple larger heaters are connected to a single location.
In this scenario, an H2 error will display due to the minimum amperage of 0.3A not being achieved.
High five! We hope this article helped you resolve your H2 error code.
If you are still having issues,
Contact Mysa Support - [email protected] as soon as possible for additional assistance.
Send us a photo of how this unit is installed. The photo should include the wiring coming from within your gang box and how they are connected to Mysa.
Additionnaly, please provide the following information:
The number of heaters connected to this unit.
The wattage of each heater.
A photo of the back of the faceplate showing the unit’s serial number.
Your order number or proof of purchase.