Well, I will tell ya I think you are doing the right thing!
Personally I LOVE my job. I mean there are days I don't want to go to work because I know its not going to be a good day right out of the gate, but almost all the time I put on my party hat and head on down. I work with a great bunch of people, where every one is like second family to me. We all get along.
What I like about the job though is I do get to put my mind to work. Yes there is a lot of grunt / dirty and downright disgusting work, but I do get into some troubleshooting as well and really get to use my brain to figure out why something isn't doing what it should. To top it off I really like the fact that I can walk onto a trouble call and have what seems to be total chaos, restored to "normal" within a short time, (depending on the origin of the problem and the severity of course) and get thanked what seems a million times over, and on a few occasions a " Thank you " card mailed to the office of all things! I get a real charge out of that! This is a trade that commands respect, and you get it thats for sure.

You have the advantage of your HVAC background which in my mind is a BIGTIME BONUS. You will be able to show up at a job or a trouble call involving some piece of HVAC equipment and know the inside of it like the back of your hand as in what values should be measured or observed, what the function of each control or device within the unit is supposed to do, even what sounds the thing should or should NOT be making correct ( All I know is scroll compressors sound funny, are loud and apparently self destruct if the phase rotation is backwards.. So I have been told anyway.)
Trust me I think its a step in the right direction and you will do good!

A.D