Odd smell from heat pump when switched back to cooling mode

[mattf82]

Had a warm day and wanted to cool the house off a couple of degrees, turned on cooling mode for the first time this year on my heat pump. Got a sweet smell which I haven't had in heating mode. Can this be common when switching modes for the first time? Functioning great temperature wise.

[SerafinsAC]

If it's humid where you're at it could be a bit of condensation mixing with the dust in your condensation pan and drain but it shouldn't cause a sweet smell.