yb900 Posted November 10 Share Posted November 10 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! Link to comment Share on other sites More sharing options...
MikeSharp01 Posted November 10 Share Posted November 10 The ecodan must be working if the water is heating unless the water heating is done by something else? E.g. immersion heater. If it is heating the water I would look at the changeover valve(s) - maybe it is stuck in water heating mode and the HP is getting a good go signal for that and the error only occurs when heating is requested but it does not get the positional feedback from the valve to say it iss ready to direct the water round the heating. Link to comment Share on other sites More sharing options...
LA3222 Posted November 10 Share Posted November 10 Do you have any y line strainers installed? Xouple of years back I noticed flow was really low, eventually thought to check tge strainer to find it was gunked up - flow improved a lot once I'd cleaned it. Link to comment Share on other sites More sharing options...
trialuser Posted November 10 Share Posted November 10 The ME Engineer app gives this for L9 Link to comment Share on other sites More sharing options...
yb900 Posted November 18 Author Share Posted November 18 On 10/11/2024 at 06:46, MikeSharp01 said: The ecodan must be working if the water is heating unless the water heating is done by something else? E.g. immersion heater. If it is heating the water I would look at the changeover valve(s) - maybe it is stuck in water heating mode and the HP is getting a good go signal for that and the error only occurs when heating is requested but it does not get the positional feedback from the valve to say it iss ready to direct the water round the heating. 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. On 10/11/2024 at 07:01, LA3222 said: Do you have any y line strainers installed? Xouple of years back I noticed flow was really low, eventually thought to check tge strainer to find it was gunked up - flow improved a lot once I'd cleaned it. Would this be inside or the outside unit? I can't see any inside! Link to comment Share on other sites More sharing options...
sharpener Posted November 18 Share Posted November 18 3 hours ago, yb900 said: 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! Could be either inside or outside. They have put a Adey magnetic filter indoors on mine, easier all round as it incorporates iso valves. If behind the outside unit and covered with lagging not easy to identify. Link to comment Share on other sites More sharing options...
yb900 Posted November 18 Author Share Posted November 18 27 minutes ago, sharpener said: Could be either inside or outside. They have put a Adey magnetic filter indoors on mine, easier all round as it incorporates iso valves. If behind the outside unit and covered with lagging not easy to identify. 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. Link to comment Share on other sites More sharing options...
sharpener Posted November 18 Share Posted November 18 No, unless it is completely choked just clean it out, reassemble and re-open the service valves. Do the same all over again after a day, a week, a month depending on the rate it collects grot until it eventually slows down. On 10/11/2024 at 00:04, yb900 said: When letting out some of the water there is a little black debris. This doesn't sound like a blocked filter though. You may have an entirely different problem, like the HW diverter valve which seem very prone to fail. 1 Link to comment Share on other sites More sharing options...
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