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Community and Q&A

Minisplit ice and pan heaters

Matt_Michaud | Posted in Mechanicals on

We recently had a Mitsubishi FH12NA hooked up.  Its been running for 6 days with a few below zero nights (northern NH).  The ice formed below the pan is substantial (I will try to add a picture after as this post keeps erroring).  There does not appear to be any ice on the coils, just a 1/4-1/2″ coating the tray.  The unit does not have a tray heater, an energy hit I was hoping to avoid.  My local installer has the FH15NA at his house without the pan heater and said it wouldn’t be a problem.  Should I be worried?  How much ice buildup is normal?  This ice mound is going to get bigger (obviously a tray heater won’t change that).

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  1. Matt_Michaud | | #1

    The ice image:

  2. Expert Member
    Dana Dorsett | | #2

    As long as the drain isn't plugged by the ice an icicle off the bottom of the pan isn't a big deal, but I personally would be keeping a close eye on that!

    A few minutes with a heat gun (a hair dryer is fine) every few days during cold snaps is usually enough to manually de-ice the mini-split if the drain is being plugged, but installing the automatic pan heater might make it easier to sleep. You may need to use rock salt or other sidewalk de-icers to keep walkway ice under control.

  3. Deleted | | #3


  4. Expert Member
    Akos | | #5

    You'll definately get a lot more ice. I'm in warmer climate but by the great leakes so more humid, come mid February there is usually a pretty thick layer of ice under the unit if there are no warm spells.

    You never want the ice to build up on the tray to the point it covers the bottom of the coils. This can quickly cause them to snap and leak.

    So keep an eye on it, heat gun as needed or just install the pan heater and never worry about. I consider the operating cost of that cheap insurance.

  5. Matt_Michaud | | #6

    Dana & Akos, thank you for the responses. Insurance and sleep at night seem like good reasons to install the pan heater, I am ordering one. Last question though, have you ever insulated below the bottom of the tray? I am wondering if this might help retain the heat from the pan heater. A hole would be drilled for the drain obviously.

  6. Patrick_OSullivan | | #4

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