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Minisplit Condenser and Freezing Temperatures

user-5296010 | Posted in General Questions on

I have a Mitsubishi outdoor unit mounted outside that will be used for basement cooling/heating. The project is running longer than expected (surprise, surprise!) and the mini-split probably won’t be connected and provisioned until late November, so we’ll most certainly have some nights dropping below freezing before then. Is it an issue for the unit to drop below freezing when it’s still in a factory charged, not hooked up/running state? Assuming the unit has R-410A refrigerant, poking around the WWW, it seems the freezing point is ‘not determined’, but if the boiling point is -54 F, the freezing point must be much lower, so hopefully I’m worrying about a non-issue. Also, are there any special considerations when provisioning a mini-split in cold weather?

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  1. walta100 | | #1

    Freezing will not be a problem. Do be sure to keep the fitting where the copper line will connect clean and dry.


  2. Expert Member
    BILL WICHERS | | #2

    A good way to protect those fittings is to use the telecom cable taping trick. Get some of the GOOD electrical tape, such as Scotch 88. Wrap a layer over whatever you are trying to protect with the sticky side out (away from the thing you're wrapping around). Stretch the tape while you're applying it. After you put on the sticky-side-out layer, put another layer over the that one, but this time in the "regular" way with the sticky side facing inwards. Overlap the first layer just a bit at the end so that the second layer makes a seal to the object being protected.

    This gives you a good seal, and the inner layer with the sticky side out makes sure the tape adhesive doesn't contaminate the thing you're trying to protect. Remember that part of the key to getting a good application is to stretch the tape while you're applying it. I stretch it about maybe 20-30% or so as I'm applying it, keeping constant tension. I've sealed some electrical connections this way that have been fine for 15-20 years (and counting). If you need the tape to last longer, add a few more layers.


  3. user-5296010 | | #3

    Thanks to you both for your responses!

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