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Mitshibishi Mini-Split No longer cooling

I installed a Mitsu Mini-split Mr. Slim in 2014 and it worked well until last August when I first turned it on and it would not cool. ( I have a low cooling load due to a passive/superinsulated home)
I had a tech come out and he thought I had lost coolant. He did ot find anything obvious to cause this but tightened a few fittings and pressurized the system and left it for a few days with not loss. He then recharged it and it ran fine last summer. We used the heat a few times this winter and this spring tried the A/C and it is no longer cooling.
It is currently blowing warm air out when on heat but just room temp air when on cool. Does this mean the coolant has leaked again or some valve is failing? I there a light that comes on on the unit itself to signify that the coolant has left the system or is low to signify a slow leak?

thanks
Supe

Comments

  • NY_Rob
    NY_Rob Member Posts: 1,370
    My Mini-Split (Panasonic) has a series of LED's on it's controller board. On an error- you note the position number of illuminated LED's (maybe #2 + #5 +#7 illuminated) and look up that pattern in the unit service manual- that will indicate the fault condition.

    Without looking at the diagnostic LED's (or whatever your unit uses) you're just guessing at the problem. My unit had a $5 thermistor go bad after four summers of flawless operation.

    You need to get a competent tech to open it up and look for fault codes. Mini-Splits are usually 240v... don't mess around with them.



  • GW
    GW Member Posts: 3,991
    If it blows heat but not cool you don't have a low ref issue
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    www.wilsonph.com
    [email protected]
    newagedawn
  • newagedawn
    newagedawn Member Posts: 587
    low refrigerant, need to find the leak with some nitrogen, the flare fittings are infamous for leaking, if you find the leak use leak lock to seal it
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 8,525
    If it heats but wont cool it's probably not a refrigerant issue but a control or reversing valve problem
  • GBart
    GBart Member Posts: 753
    it's broken :D
  • NY_Rob
    NY_Rob Member Posts: 1,370
    How/why did this one post wonder thread get resurrected from the dead?
    GBart
  • ratio
    ratio Member Posts: 2,727
    There's a few new accounts that necro old threads & add little, or non sequiturs. They all seem to smell alike. I could be mistaken, but I keep expecting a flurry of ... purchasing opportunities... to come along.

    And if you're one of the new accounts reading this post, let me know & I'll quit expecting to be spammed by you. :wink:

    1Matthias
  • 1Matthias
    1Matthias Member Posts: 148
    ratio said:

    There's a few new accounts that necro old threads & add little, or non sequiturs. They all seem to smell alike. I could be mistaken, but I keep expecting a flurry of ... purchasing opportunities... to come along.

    And if you're one of the new accounts reading this post, let me know & I'll quit expecting to be spammed by you. :wink:

    Hey, I've got a bridge I could sell you if you want... ;P
    ratio
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