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  1. #1
    Join Date
    Mar 2013
    Location
    UK
    Age
    33
    Posts
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    Mitsi VRF not cooling



    Hi all.

    Sorry for the long post.

    Got a VRF that system playing up, every couple of days all indoor units stop producing cold air. Carried out a valve reset twice now and it keeps reoccuring. It works in heating fine. The smaller units produce next to nothing in cooilng and the larger units are cold next to the lev. All controllers show 5c off coil temperature in test mode.

    I replaced an lev on an indoor unit a year ago and its the only unit out of 13 that is producing below 10 off coil. Im guessing i may have got it too hot when braizing it in and now its stuck open.

    I carried out the valve reset 3 times today before it all came back on with all units producing around 11 off coil.

    The total demand of indoor units is slightly higher than the condenser is capable of but were talking like 1kw, but not all units are ever on at once.

    There are no issues at the condenser other than the condenser off coil temp is only around 35c and ambient was 30c.

    Mitsi technical pointed me towards lev3 on the distribution box and said to release it quarter of a turn but it doesnt seem to help it in any way at all.

    Any help appreciated



  2. #2
    Join Date
    Feb 2011
    Location
    England
    Posts
    36
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    0

    Re: Mitsi VRF not cooling

    If you suspect you have damaged the valve when you replaced it this could be the issue. If the valve is stuck open the best way to check would be to turn that indoor unit off while you run A couple of units on the system and feel the suction line... if it’s cold after 5-10mins Id suspect it is passing and requires replacing. You may also be able to hear refrigerant hissing throughly the coil or even use the dip switches to check the suction pipe temp but it will be pretty obvious if it’s passing I’d have thought.
    dont be to concerned about the demand of the indoors on the condenser aswel, Mitsi allow 150% diversity if required.

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