Hi there. I was wondering if if can get any help in this situation. I hire a pool guy last February to install my pool equipment. Just to make the story short none of the is wire properly. He just used a 30 amp circuit breaker put a wire nut and connect intelliflo VS and heater together. I was able to separate this and dedicate a 20 amp GFCI Siemens recommended for this. Another 20 amp GFCI for intellibrite pool and spa LED lights. Another 20 amp not GFCI tendem single pole breaker. My sub panel is square D. So I got a master temp 400 natural gas heater that is factory wire for 240 vac. Since I want a dedicated circuit brakes as well; can I use regular 20 amp circuit breaker doble pole 240 v with a 12 awg even though the manual says 15 amp 14 awg ? And does it have to be GFCI which are more expensive $130 around or ever higher with Siemens brand. Thanks in advance for any help.