Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Fujitsu Mini Split charging question

I have a 36000 Fujitsu 2 head system still under warranty . Company has been chasing leaks since install in 2019 . I read here there where batches of bad line sets from manufacturers that year . The kept telling me it was it was Flares leaking . So it was down 2 lbs of R 410 A this season again . Leaked tested with Nitrogen today . Finally they said bad line sets and found 1 bad 18000 BTU head leak . They ordered everything and are telling me 2 to 3 weeks . They pulled the disconnect and said im dead in the water till parts come . So my question is :
Can they evacuate the nitrogen contaminated R 410 A and recharge it so at least i can use the system for however long it takes for the parts to arrive ? Or is there some sort of EPA regulation that your not allowed to recharge a leaking system or are they wrong . For reference, it took 2 heating and cooling seasons to loose 2lbs of R 410 A . Full charge is a little over 7 lbs . TIA


  • pecmsg
    pecmsg Member Posts: 4,949
    1st red flag: Using the factory flairs.
    2nd red flag: Putting N2 in with the R-410A still in it.
    3rd Red Flag: No way of knowing how much refrigerant is in there without pulling and weighing.

    Can the N2 be separated Yes.

    2 - 3 weeks? Depending on the model there available.

    With the system leaking pulling a vacuum is out of the question.

    You just might have to wait.

    I'm not impressed with this tech and or contractor.
  • misterheat
    misterheat Member Posts: 158
    Thanks for the reply . After raising a little hell with the company they got the parts in today and im on the schedule for next Thursday . Couple more questions :
    1st question - they added the nitrogen to help look for the leak . They told me it helps push the R 410 A and makes it easier to detect with a sniffer instead of a pressure test ? Was that the right move to find the leak ? next week Will they do all the swapping first and then check for leaks with existing nitrogen contaminated r410 a /with out firing up the system ?
    or should they evacuate the contaminated r 410 and then pressure test ? Im new to mini splits and im
    Just trying to wrap my head around the proper procedure and order of operation . With only 1 year left on the outdoor unit , i want to make sure they dont F anything up again. Thanks again
  • pecmsg
    pecmsg Member Posts: 4,949
    edited June 2023

    They add N2 to the charge to raise the pressure. Not needed to leak check. Now they’ll just dump the charge rather than recover as EPA requires, claiming it’s a leak check trace amount of refrigerant.

  • EdSheridan
    EdSheridan Member Posts: 16
    edited June 2023
    Well I know this doesn't help you at this point - but the correct thing to have done is to recover the refrigerant into a clean recovery cylinder down to 10mmhg then stop, so as to not pull contaminants from the leak(s) into the refrigerant.

    Then pressurize the trace refrigerant left in the system with nitrogen and check all the flare connections. This would also be the only way to approximate the amount of refrigerant loss.

    Like pecmsg said, the factory flares are usually poor quality and leak

    Something to know is that Mini-Splits, can't be re-charged based on calculating the low-side and high-side refrigerant saturation pressures. It not recommended to just "add refrigerant" to a mini-split because you can damage them by overcharging. If you hire someone to diagnose your Mini-split and their solution is to add refrigerant, they are just guessing on quantity, unless they recover it all then weight in the total by the manufacture's specs. i.e. the factory charge (on the unit name plate) plus any additional based on the lengths of line sets.


  • mattmia2
    mattmia2 Member Posts: 9,938
    BTW, the EPA rules do not forbid you from charging a leaking system, at least not a small system that contains a couple pounds of refrigerant.