yb900

I have the magnetic filter indoors. I watched the mitsubishi videos on YouTube re L9 and they show how to release the bottom and check for debris. If there is some debris though, is the idea you just keep releasing the water until it runs clear and then re-pressurise. In the video they just run it for a couple of seconds and don't really say what to do beyond this.

We do have an immersion tank but it's all connected as far as I know. You might be right about the changeover valve. I can feel the hot water pipes warm but not the heating and wonder if that valve has gone. Would this be inside or the outside unit? I can't see any inside!

Our ecodan started with an L9 error a few days ago and I cannot seem to find the problem. The pressure was at about 1.2 so increased to 1.7. This didn't solve the problem. The hot water is working fine and the tank is heating up no problem on schedule but the heating upstairs (rads) and downstairs (underfloor) will not work. I followed the advice of the mitsi youtube videos and had a look at the filter. When letting out some of the water there is a little black debris. Flow rate is at 0!! It just happened all of a sudden in Thursday morning. Pump speed was/is set to 5. Any ideas what else to try? At this point I'm stumped and calling out the engineer, but I hate not being able to fix it myself!

I have also tried to turn off the freeze stat but like the poster above when I go to the settings and select the relevant one to get to the freeze stat is asks says "system shut down - yes, no". I'm also not sure whether to go ahead and do this. Can anyone confirm that when you save and exit the settings the system just comes back on or is there a process for this? Any help much appreciated cos the noise at night while it whirrs away for no reason is driving me batty!