These solenoid valves are somewhat cheap, but they're only for water. One of them is Normally Open, and the other is Normally Closed. This way, I can connect them to the same circuit and one will be open while the other is closed. I will place them so that the default configuration is de-energized for safety reasons. They will only be energized when bypassing to the radiator shroud coil according to a timer. They're crappy pictures. The one with the larger nut on the coil is the N/O valve.