For inductive loads (i.e. solenoid valves), adding a diode in parallel with the load will greatly increase switch life.  See the link to the right for an in depth explanation.  Diodes can also be used to operate a diverter or dump valve type function, where an additional valve activates along with any of the other functions.

Diodes, how and why

When and why you should install diode protection, choosing the correct size and how to install them.

Diode Boards

Our new DP-10 and DP-04 diode boards can now be installed internally on our L and S grips. This means no external diode case to deal with. Additionally, all diode packs now have the diverter output feature built in, giving both diode protection and the ability to operate a diverter or dump valve in one small package.