What type of relay should I use to control a 24 VDC solenoid?

The Form C relays contained in many Sealevel digital I/O products are the best choice for switching highly inductive loads like solenoids. Other relays, including reed relays and solid-state relays, are not well suited for this application. Reed relays may work temporarily when switching inductive loads, but will be prone to pitting and welding that can eventually cause the relay to fail. Solid-state relays have a leakage current which results in a relatively significant power loss for these applications. In contrast, Form C electromechanical relays are efficient and have switching contacts suitable for handling heavier loads and some arcing without a decrease in switching function.