Why is my mini split freezing up

[tallgrass1951]

Just recently my outside unit has started freezing up. Is this normal in very cold weather or do I have a refrigerant issue? It was installed new in June of 2018. I bought the arctic unit that works in colder weather. It still heats, though not as well as before it started freezing up.

 

[Kaizen]

What unit and btu is that?


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[yeldogt]

What's the specification ? It looks as if it is not going into defrost ... units w/o a pan heater will often ice up on the bottom as the water from the defrost cycle refreezes. Yours has a look of no defrost and the unit slowly fills up with ice.

with the coils so cold any humidity in the air will freeze as the water vapor crosses the coils .. any exhaust vent near by is a no no with a heat pump near by

 

[tallgrass1951]

It is a pioneer 18,000 BTU and has a defrost cycle. Does not have a pan heater. No other vents nearby. We have has some sleet and mist with high humidity while below freezing. It does go into a defrost cycle on it own.

 

[kelpaso1]

Mine has done that on occasion although not that bad. I find the defrost cycles are not long enough. When mine freezes up I shut it off and and throw a blanket over it and put a small 1500 watt heater under the blanket for an hour to thaw it all out.

 

[Kaizen]

Maybe tent it with clear poly on a sunny day with it off to let it completely melt. See if the problem continues or hopefully just weather ice


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[yeldogt]

None of mine have ever looked like that -- they get a slight coating of frost .. but, not enough to block anything.

If it's working to design -- The design does not allow for proper defrost length or temp.

 

[pattenp]

Either the defrost cycle is not working correctly or the refrigerant is low. Check the inside air filter to make sure it's not super dirty. I suspect most likely low refrigerant.

 

[Milton Shaw]

With the unit freezing from the bottom to the top, the defrost is not working right or maybe not at all. Put unit in a/c mode and it will melt the frost off immediately, faster than trying to put a heater on it. If low on refrigerant it would just be freezing probably only at the bottom or top not all the way up. Defrost timer or control board is probably what is not working. Get into the manual and wiring diagram and look to see what is not working.

 

[pattenp]

Low refrigerant can cause the condensing unit to completely freeze up over time. The defrost cycle doesn't keep up and eventually the unit will become fully frozen.

Edit: You need to call A/C company to check it.

 

[NZGarage]

What can cause an icing issue with my Fujitsu unit is turning the unit on in the morning and having the inside fan on high, with no other heating going in the house.

What I do is leave it turned overnight in frosty/snow conditions and have the inside fan on auto and make sure there is some other background heat also on.