Duo Therm Heat/AC function question

If it is a new unit, I would look at getting the dealer to replace it under warranty. The usual cause of a sticking solenoid is a small piece of trash or debris that was introduced into the system when it was built. The valve operates by teflon slides moving from one side to the other and it doesn't take much to hang it up. Not common, but it does happen, and it's likely it will stick on you again. Replacing the reversing valve is labor intensive and requires a moderate amount of skill and experience to do it without burning it up with the torch and most shops are not going to want to do it. I've been changing them for 15 years and my pucker factor still goes up when I have to do one on my marine units.

You can give the valve a light tap on the end with a wooden stick if it sticks again, but noting heavier.