VIAIR 12V Automatic Pressure Switch with Relay — Black 110/145 PSI, 1/8" NPT Compact

This compact pressure controller replaces manual cycling by sensing tank pressure and switching your air compressor on and off at preset setpoints. Designed for automotive and light‑duty pneumatic systems, it integrates a relay to handle higher electrical loads while protecting the compressor’s electrical contacts. The unit connects to standard fittings and fits where space is limited.

How does the VIAIR 90111 prevent compressor overrun?

The switch continuously monitors the air line and actuates the compressor only when pressure drops to its lower threshold. Once pressure climbs to the upper threshold, it cuts power so the compressor stops automatically. This removes the need for manual monitoring and reduces the risk of exceeding the compressor’s rated pressure.

• Automatic on at 110 PSI, off at 145 PSI
• Maintains safe operating pressure range for most 12V compressors
• Prevents continuous running that can cause overheating

What electrical and mechanical features does it include?

The 90111 is made for 12‑volt systems and includes an internal relay so the switch contacts are not carrying the full compressor start current. The stronger relay extends service life and allows reliable operation with larger compressors. Mechanical connection uses a standard 1/8" NPT male port for straightforward plumbing to tanks or manifolds.

• Integrated relay for higher current capacity and durability
• Compatible with 12V electrical systems
• Pressure sensor fits 1/8" NPT male port for easy installation

How simple is installation and maintenance?

Installation is typically straightforward: mount the switch, connect the 1/8" NPT sensor to your tank or line, and wire the 12V supply and compressor through the relay terminals. Because the relay reduces wear on the primary switch contacts, routine maintenance intervals are extended compared with non‑relay switches. Basic checks of electrical connections and thread seals are all that’s normally required.

• Mount, plumb 1/8" NPT port, and wire to 12V and compressor
• Relay reduces contact wear for lower maintenance needs
• Compact footprint fits tight engine bays and equipment panels

What applications is the VIAIR 90111 suited for?

This pressure switch is ideal for mobile air systems, on‑board compressors in trucks and SUVs, small workshop compressors, and pneumatic accessories that need reliable automatic pressure control. It’s best for setups that require a robust on/off control around the 110–145 PSI range and for anyone who prefers a low‑maintenance switch with a built‑in relay.

• On‑vehicle air compressors for off‑road, work, or utility use
• Small shop or portable compressor systems
• Pneumatic accessory circuits needing preset automatic control

Who is this for: The VIAIR 90111 suits vehicle owners, fleet managers, and DIY mechanics who want a compact, dependable automatic pressure controller for 12V compressors. If you need reliable automatic cycling at 110/145 PSI, reduced electrical wear via an internal relay, and a standard 1/8" NPT plumbing connection, this switch is a practical upgrade for protecting and simplifying your air system.