Why is my Mitsubishi Ecodan not heating up the tank?

@Chris_OVO The thermistors were working fine, and I could see their value in service menu and it was matching the water temperature. However, when it came to the water circulation pump, there was a problem with that. For future reference, there was a slide switch on the pump motor body where it wasn’t fully in position. Sliding that to full on resolved the issue, restarted the system and my water tank temperature raised to 50 in one or two hours.

Hey @hamedj 

Glad to gear you managed to get that all sorted in the end, and thanks for coming back to update us about it!

If you’ve ever got any questions or queries in future, please don’t hesitate to stop by.😊

​@hamedj 

I have the same problem, can you add a picture of what exactly you moved?

Thanks

​@hamedj ​@Mimi 

The installer said that some kind of internal filter might be there and that replacing it would cost about 850 euros. I hope I don't have to do that.

Hi ​@raagraiko ,

I don’t have a photo of my unit at the moment, but if you open your boiler front, you should be able to find the pump above the heat exchanger. there must be a switch on the body of it where you should move it to make it working. Look at the photo below, switch is shown on top. Mine was similar to this.

​@hamedj 

Thank you for answering. 

Mine has been in position 2 for about 3 years since installation. I also tried position 3, but it didn’t help. 

When i restart the device, the flashing LJ light disappears and the boiler starts heating, but after a few hours the error comes back. I probably have a more serious problem. 

Hey ​@raagraiko,

I’m happy to see ​@hamedj has offered some advice. Have you been able to ask your installer about the error message and if there’s any other troubleshooting you can do? 

Hi everyone, 

I have the same issue (LJ error message) and can’t figure out how to solve it. I read the previous posts, i tried the steps mentionned (check the thermistors and the pump) but to no avail.

The thermistors seem to work fine. I can see their value in the service menu, and the temperature rises and drops correctly apparently. 

The pump activates when i restart the system, heats the water for a while then stops, and the error message appears. I tried changing the button on the pump (from 2 to 3 and vice versa) but that doesn’t change anything.

The system heats the water for a while (but not to 50°, it generally stops before that) and then the error appears. I have to restart the system each time I want some hot water…

My installer doesn’t know what’s going on, and must try to contact Mitsubishi directly...

Did anyone manage to solve this issue ?

Thanks.

Hey ​@Jerry05 

Welcome to the community!

I’m glad to see you’ve already tried out the steps mentioned above. As you say, sounds like it’ll be worth checking in with Mitsubishi support directly on this. 

I know others have had to do the same for many reasons and it sounds like they usually have a good experience trying to get what they need from them, so hopefully they’ll be able to help you with this one.

Do let us know how you get on, and maybe some of our community will pop back in the meantime.

Hi, 

Thank you.
As I’m in France (I’m French), I’m going to try to find a French contact for Mitsubishi.

I decided to ask my question here on OVO because I couldn’t find anywhere else someone with a similar problem (same error code).

I will contact my installer again and Mitsubishi if I can.

I’ll let you know.