Ecodan ASHP heating not working

jonso100 Posts: 2
First Post
edited 23 January at 2:33PM in Heat pumps
As per the title, we have hot water but no heating. With reference to this thread (I've added spaces as I can't post links) https:// /discussion/6402486 /mitsubishi-ecodan-ashp-no-heating/p4 I have checked:

- desired temperature is set to 22 but it doesn't get above 16
- paused water so it was just trying to do heating with no joy
- as per the other thread, I went into the loft and checked out the 3 port valve - all 3 pipes are hot, including the B pipe
- but I followed the B pipe and there is a part where the pipe becomes colder 
- video of my findings is on you tube. I can't post links but search 'ASHB blocked?' or remove spaces from this link: https:// /watch?v= HEunlBcq-9g

So I guess the question I'm asking - is it blocked? Is there anything I can do apart from calling in a professional?
Any help appreciated!


  • tacpot12
    tacpot12 Posts: 7,830
    First Anniversary Name Dropper First Post
    The fact that the B  pipe is cooler suggests that there is insufficient flow past that point. I think you could try tapping with the handle of a screwdriver or similar, at that point in the pipework, to see if you can break up or free the obstruction. Tap gently though. Remember copper is a soft metal! ( I assume this is a copper pipe where you can feel there are warmer and cooler sections.) 

    If that doesn't work, I think it would be time to call in some professional support to diagnose the problem. Try to get someone who knows the Ecodans well.  
    The comments I post are my personal opinion. While I try to check everything is correct before posting, I can and do make mistakes, so always try to check official information sources before relying on my posts.
  • espresso
    espresso Posts: 16,447
    First Post First Anniversary Combo Breaker

    I don't believe that this is an ASHP specific problem and the heat pump is clearly producing heat.
    The thing that you point to is an auto air vent located at the highest point in the central heating pipework and this should vent excess air.
    These valves have a float inside them which can jam or it could simply have some crud inside preventing the air vent from venting correctly.
    Focus on getting air out of your system before calling anyone out.

    :doh: Blue text on this forum usually signifies hyperlinks, so click on them!..:wall:
  • Rodders53
    Rodders53 Posts: 2,080
    First Anniversary Name Dropper Photogenic First Post

    Certainly check if air is trapped in pipework beneath that brass 'bottle' automatic air vent.  The plastic vent is sometimes screwed down tight (closed) rather than slightly loose (auto) to avoid water leaks?
  • Thanks for the replies.
    tacpot12 - had a tap around all the pipes but sadly no magical resumption of heating!

    Rodders53 - The plastic vent wasn't tight but there was water in it; is that to be expected or should it have been dry if it's functioning correctly?

    espresso - any suggestions to try and clean the vent out apart from giving it a few taps? Would I be able to poke something down through the hole - would that help? Also "getting air out of your system" - do you think that's the cause? If so, how do I go about doing that? Any good sites / checklists that I could reference?

    thanks agian
  • markin
    markin Posts: 3,716
    First Anniversary Name Dropper First Post Photogenic
    Bleeding all the rads would be a start
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