We have the Wilger duo-rate nozzle bodies on our 4420 so it has:

1. Boom pipe

2. Saddle mounted to pipe

3. A "through" nozzle body mounted to the saddle

4. A 5-way turret nozzle body mounted to the "through" nozzle body.

We fertilized with this sprayer for the first time this year. We do it by switching back to PWM (as opposed to using AIM Command) which shuts the AIM Command solenoids off. Then we manually turn the turret style nozzle body on by twisting the on/off thumb-wheel and we fertilize with it while not using AIM Command.

Every time after fertilizing when we switch back to herbicide we find that several of the AIM Command solenoids are not working and we have to replace them. Is the sprayer just getting old enough (2,500 hour or so) that we're going to have to replace a bunch of AIM Command solenoids or is it that the fertilizer is causing us issues?

I thought since the AIM Command was off that would prevent that little plunger from pulsing up and down and I assumed that all of the fertilizer would go through the through nozzle body and no fertilizer would get on the AIM Command solenoids but maybe I'm missing something?