Given the (presumed) frost giant, the rainbow, spirits everywhere, and your hint of melodic death metal, I'm guessing it's something by Amon Amarth, but idk what song specifically.
If the concept of a reversing valve is wholly alien to you, I cannot recommend you DIY your issue. Just hire someone, it goes beyond convenience or annoying risks, it's your safety that I'm questioning. Frostbite, electrical shock, poisoning, risk of explosion, severe burns, suffocation, there are so many ways that trained techs get hurt or killed when they don't respect the safety element. No way in hell am I going to tell a stranger on the internet to take that risk for themself or someone around them.
Please just hire someone.
Edit: just realized you're not the OP. Still gonna leave this up. This kind of work is simply not suited to being done by non-professionals.