Looks like snipe might be wrong. I have two dead clip maxi's. I'm not sure if it is a waterproofing issue... I didn't waterproof them, as I too believed they were waterproof. Honestly, they really should be! I took a dremel to a dead one today. It is a electromagnet which is completely potted, ZERO water should be able to get through. I really don't know what's gone wrong with them. I don't think its a 'rated pressure' problem either. If I steal the electrics from a 'working' valve, the dead valve functions A-OK. Hooking up my ohmmeter, a 'good' valve is rated @ 30ohms (or kohms... I can't remember); but both of my dead ones are rated @ infinite. In other words I have a broken circuit. What could have possibly broke them? Perhaps the battery voltage pushed their upper limit? (wouldn't that suck) Perhaps the noise coming from the motor gave them some sort of transient problem? Not likely as these two weren't' hooked up while the motor was running Pure heat? 150psi requires more magnetic pull than 100psi... so perhaps the electrics tried to compensate when they shouldn't have? Really unlikely.
Solenoids should be and are waterproof; the windings have to be insulated to prevent a short between windings under dry operating conditions. If someone was running a higher voltage, they could have put too much current through the coil and overheated a section of wire. Or, if the higher than rated gas pressure was causing the slug to vibrate vice open completely, one could get a torque exerted in the vertical dimension of the coil causing a separation in that. Just getting wet won't kill a solenoid.
That's what I thought Was most likely too... But really didn't want to believe it... They are 12v, my batt is 12v... And these two haven't been activated while the motors were running... So it's just the battery.
