I am going to use this: http://misolie.com/showshop.asp?id=358
valve for a HERMS bypass loop and plan on controlling it with an Auber SYL-1512A PID in on-off mode. The idea is that by incorporating a bypass loop I can contol the HLT temperature separate from the mash temperature. Anyhow, I have a 24V transformer for my gas valve, so would I be better off stepping down to 12VDC from that or just get a separate 120VAC to 12VDC transformer? I am leaning toward the later, but what I am confused about is if I will need some kind of relay? My wiring knowledge is basic, so any diagrams would be great! I also plan on using an RTD sensor at the outlet of the HERMS coil. Any help would be appreciated.