Air Compressor Pressure Switch, 105/135 PSI #05C331

The pressure switch controls the cut-in and cut-out pressure of the air compressor.

If your valve is leaking on the side of the switch, do not order this part. Order a check valve instead.

PSI rating: 105/135 

1. Search by Air Compressor Model Number (Most Accurate Method):

• "Search parts for: Select a model to find Exact Fit Parts": This is prominently featured on the homepage and various category pages (like the "Air Compressor Parts" section).
• How it works: Input your air compressor's make and model number (e.g., "Husky H150P," "Porter Cable C2002," "Campbell Hausfeld HL4300").
• Result: The website then filters its entire inventory to show only the parts confirmed compatible with that specific compressor, including the correct check valve. This is the most reliable method as it removes guesswork.

2. Visual Inspection and Matching Key Specifications:

If the model number isn't readily available or you want to confirm:

"How-To Choose The Correct Check Valve" Video/Guide: Master Tool Repair has a dedicated guide (and likely a YouTube video, as per search results) on the site explaining how to identify the correct check valve. This is crucial because check valves have specific characteristics.

• Key Specs to Look For and Measure:

  • Thread Size (MPT, FPT, Compression): This is paramount. Check valves have different connection types and sizes. You need to measure:

    • Male Pipe Thread (MPT): Measure the Outside Diameter (O.D.) of the male threads. We provide a guide (e.g., if O.D. is 1", you need a 3/4" MPT; if O.D. is 3/4", you need a 1/2" MPT – the MPT size is typically 1/4" under the O.D.).

    • Female Pipe Thread (FPT): Measure the Inside Diameter (I.D.) of the female threads. Similar to MPT, the FPT size is often 1/4" under the I.D. (e.g., if I.D. is 3/4", you need a 1/2" FPT).

    • Compression Fittings: Measure the I.D. of the compression fitting or the O.D. of the discharge transfer tube that goes into it.

    • Flare-style Check Valve: Measure the O.D. of the male flare threads.

  • Unloader Port:

    • Does the old check valve have a small side port for an unloader tube? Most do.

    • What is the size of that unloader port? (e.g., 1/8" FPT, 1/4" Quick Connect). This port connects to the pressure switch to "unload" the pressure in the head when the compressor cycles off, making it easier to restart.

  • Material: While less about compatibility and more about durability, noting if the original was brass, steel, etc., can help. Most are brass.

  • Orientation: Check valves are one-way. You need to ensure they match the flow direction or the type of valve (e.g., in-tank, inline).

• Serving Customers Since 1994: For more than 30 years, Master Tool Repair has been a trusted source for air compressor parts, repair kits, and expert guidance.
• Quality Parts: We stock a wide selection of high-quality OEM and aftermarket parts for all major air compressor brands.
• Customer Service: Our knowledgeable, friendly staff is dedicated to helping you find the right parts and solutions for your needs.
• Competitive Prices: We offer quality parts and services at fair prices to help you maintain your system as cost-effectively as possible.