H2 On My Mysa Thermostat – Why And What To Do?

Mysa thermostats are reliable smart devices for controlling your home's temperature setup. However, Mysa could also malfunction, like the H2 is showing on its screen. Here's why this issue occurs and what proper action you should do to fix this. See for yourself the answer we've found below!

The H2 fault is due to your Mysa thermostat failing to communicate with your heater. In this case, inspect thoroughly or install its wiring connections correctly to fix this H2 error for good.

Keep in touch because there's so much knowledge we are going to share with you below. As we will address the other Mysa thermostat error codes. We will also provide the easy steps of how you safely wire your Mysa thermostat. So keep on reading to learn all of them below!

man at home adjusting thermostat with device on the wall, H2 On My Mysa Thermostat - Why And What To Do?

What Does H2 Mean On A Thermostat?

Your Mysa receives the electrical load, controls it, and then sends instructions to your heater to switch "ON" or "OFF." The H2 error will prompt if your Mysa attempts to transmit an order to the heater but receives no response.

This indicates that Mysa is not picking up a heater load in electrical terms. This most likely results from a problem with the wiring connecting Mysa and your heater.

What To Do If Mysa Thermostat Is Going Unresponsive?

These issues are mostly the result of improper wiring installation. You can avoid this by following Mysa's proper wiring setup. Anyhow, if you are already facing such a problem, then checking its wiring can help fix this.

Person adjusting the home temperature on a smart thermostat

Here are a few steps you can use as a guide to check your Mysa thermostat wiring:

  • Remove the thermostat plastic cover, which acts as its shield preventing the device from sensing signals.
  • If the problem continues to appear, you can try shutting "OFF" its breaker and turning it "ON" again.
  • You should also ensure that the Mysa's device ground wire is securely in place on its gang box.

Note: When performing random checkups in your Mysa thermostat, ensure to switch "OFF" its power source first.

What Are The Other Common Mysa Thermostat Error Codes?

An error code in your Mysa thermostat implies that it's functioning well and can evaluate your system. Even so, this also involves quick attention and assessment of what specific action it requires to remedy the issue.

Here are some common error codes that you may come across and how you deal with them:

Error Code I3

This type of error code results from the sensor wire not being properly attached to the Mysa's in-floor thermostat. Securely connect its wire to your Mysa to avoid this kind of error showing again on your screen.

Error Code H3

The H3 type of fault indicates that the GFCI has been tripped. Solving this problem will need you to reset the GFCI. You'll just push its button, which you often find in the right side portion of the Mysa in-floor thermostat.

Error Code H4

An error code like this one displaying on your Mysa thermostat panel is the cause of mechanical relay problems. The only best solution to this problem is to replace the faulty component.

Pro tips: If your Mysa in-floor thermostat is showing error codes that aren't included in our above's list. We strongly suggest you call your nearest Mysa's thermostat help service.

How Do You Install A Mysa thermostat?

hands Digital thermostat on the wall

Mysa thermostat is necessary for your home, and the key for it to function effectively is correct installation. Mysa thermostats are compatible with most of the 120-240V systems, such as baseboards, in-floor heating, and AC systems.

Follow our easy installation steps below for the 240V heating system:

  1. First, shut "OFF" your power breaker.
  2. Securely connect your Mysa thermostat to the 240V heating system using your wire nuts.
  3. Attach the Mysa's white wire to the circuit red wire L2.
  4. Next is the black wire into the black supply wire that has a mark L1 from your electrical panel.
  5. Proceed to Mysa's red wire and connect it to the black load wire in your heater.
  6. Now, connect the green wire to the green or ground copper wire.
  7. Ensure to house the thermostat in the wall with mounting screws to hold it still.
  8. Securely attach its faceplate to the thermostat.
  9. Switch "ON" your power breaker.

Installing a modern thermostat back of the modem

Use these steps for your 120V capacity heating system:

  1. Again, start your work by shutting "OFF" the power source entirely.
  2. Attach your Mysa's thermostat to your 120V heating system.
  3. Connect the thermostat's white wire to the white neutral wire.
  4. Securely attach the black wire to the black supply power wire in your electrical panel.
  5. Next is the red wire; connect it to the black load wire in your heater unit.
  6. Now, ensure to attach the green wire to the ground green wire.
  7. Carefully mount your Mysa thermostat to the wall using mounting screws.
  8. Properly attach the faceplate to your thermostat. 
  9. Finally, you can now turn back "ON" the power source in your heating system.

Warning! It is critical to remember that you must not displace all wires in the above steps to ensure functionality.

How To Tell If You Use A 120V or 240V?

Knowing your heating system size is crucial for the thermostat to effectively keep your comfort. There are two easy and simple ways to figure out what voltage your heater runs on. You can use these methods for most houses, but they might be not applicable in other homes of different setups.

Single or Double Breaker Switch

  • Examine your power breaker if it only has a single switch; if so, then you have a 120V.
  • If you see a double switch in your breaker, then most likely, you have a 240V.

Wire Coloring: Black/White or Black/Red

  • First, shut "OFF" the electrical box to your Mysa's thermostat.
  • You can also directly check the gang box of your Mysa's thermostat.
  • If you see black and white color wires inside then you are using a 120V.
  • Otherwise, if you confirm that it has black with red wires, then surely you have a 240V system.

Note: This process requires extensive electrical knowledge to safely perform the above's procedure!

How Do You Set Your Mysa Thermostat To Pairing Mode?

Like other home smart devices, Mysa Thermostats also can link their system via a Wi-Fi network. If either you reset or turn "ON" the device, it will go to 15 minutes of paring mode.

You can set and pair your Mysa to your account and link it to your smart device to your Wi-Fi. If you notice that the network doesn't detect your account, then probably, you have already linked it.

You can reset the thermostat to make the Wi-Fi network reappear again until your account is visible on the screen.

To correctly reset your Mysa thermostat, you'll have to:

  1. Tap simultaneously the "UP" and "DOWN" keys of your Mysa thermostat and release it after 10 seconds.
  2. Right after, the thermostat will proceed to reset mode, and the smiley face icon will show.
  3. Next, the upside-down triangle icon will prompt the indication that the device is in pairing mode.
  4. Finally, the Wi-Fi is now able to detect your device and is ready for connecting.

Note: You can also cut "OFF" and "ON" the power to your breaker to set your thermostat into pairing mode again.

How To Factory Reset Mysa For AC?

Factory resetting your Mysa Thermostat helps its system to refresh along with fixing underlying issues within its systems. Factory resetting your thermostat for your air conditioner will require Wi-Fi and remote controls.

Thermostat, Home Energy Saving showing 68 degrees

Your Mysa thermostat will go back to its default settings by:

  1. Hold all at once both "MODE" and "FAN" keys which you'll find in the right portion of your Mysa thermostat.
  2. Afterwards, a countdown will display telling you that the system will proceed to reset mode. Don't release them yet!
  3. Once the countdown is done, then this is the time to release both keys.
  4. Immediately when your thermostat turns back "ON," it will go again in pairing mode.

Can You Use Mysa Without Wi-Fi?

You can certainly set up a Mysa thermostat without a Wi-Fi connection. However, the only thing that you can have access to it is to change the temperature. You won't be able to enjoy or link the device or use the full set of services that Mysa offers.

In Conclusion

man at home adjusting thermostat with device on the wall

No matter how great and advanced your Mysa thermostat, it is always prone to malfunctions. Over time it is inevitably going to face such problems as I3, H3, H4, and especially the H2. It's critical to know why these issues are manifesting so that you can act accordingly of what right solution it needs.

We hope that by learning all of this significant information you can now care for your Mysa thermostat.

If you enjoyed reading this article, visit and read as well our other informative post below!

How To Wire Mysa Thermostat

Ecobee Thermostat High Pitched Noise – Why And What To Do?

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