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the blowback or blowdown of the safety valve is at least 2 psi and for pressures over 100 psig is 2% of the popping pressure. The blowback is adjusted with the adjusting ring on the safety valve. The blowback is the pressure less than the popping pressure at which the safety valve will reset.

Examples: a safety valve set to pop at 15 psig will reseat at 13 psig, the blowback is 2 psi. A safety valve set to pop at 250 psig will reseat at 245 psig the blowback is 5 psi or 2%.

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Q: What is blow down pressure of safety valve?
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