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The air brake safety relief valve is usually set to open at what pressure?

150 psi.

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  1. 150 psi ✔
  2. 100 psi
  3. 125 psi

Why: The safety valve sits in the first tank the compressor fills. It protects the system from too much pressure and usually opens at 150 psi.

Huh, didn't know that: If the safety valve releases air, something is wrong: have a mechanic fix it.

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Why did the safety valve never get stressed? It always let things go.
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References

Answer: 150 psi. The safety valve sits in the first tank the compressor fills. It protects the system from too much pressure and usually opens at 150 psi.

  1. California Commercial Driver Handbook (DMV) www.dmv.ca.gov/portal/file/california-commercial-driver-handbook-pdf
    The valve is usually set to open at 150 psi.
    Checked 2026-10-10.

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