I got some frost on my Sanyo ASHP last winter. Snow gets sucked into the coil.
It has a
defrost mode. It flips into cooling mode, but does not turn on the indoor fan.
It just pumps a little of indoor heat out to the coil to melt any ice.
In order to keep rain from being pulled in, I sealed our little snow roof
to the side of my house. It keeps most of the dripping water from getting on the coil.
I'm hoping the lattice will act as a snow drift barrier and keep snow from building up behind the unit.
As your Mom to check the manual (or you can check it on-line) and find
out about the defrost mode of her ASHP. Maybe she just needs to wait
a half hour for it to warm up and melt..
It might be a good idea to turn off and ASHP when it's raining on cold days,
and turn it back on when the rain stops.
When it's snowing real hard and it's blowing around, sometimes, I'll turn ours off for a while.
No sense asking for icing..
