Trumpy's advice has certainly stood the test of time....and, I might add, reflects upon the stormy history of the GHI- which is why I am also leery of the new AFCI mandates! But that's another thread....
For the past two years, GFI's have been manufactured to a different standard, one that supposedly reduces nuisance tripping with motor or compressor loads. Or, so they say...
It is interesting to note that there do exist GFI's, intended for use with older pool lights, that are set to trip at a higher level (20ma, I think). And AFCI's are essentially 30ma GFI's.
Now, if this is a 220v. piece of equipment, the GFI would be in the form of an expensive breaker. So would anything over 20 amps.
Best suggestion I can make is- call the heat pump maker and ask!
