§1065.280. Paramagnetic and magnetopneumatic O 2 detection analyzers. — Inbound Citations

(d) You may use any gas analyzer for this test. If you use a FID for this test, correct for any HC contamination in the sampling system according to § 1065.660. If you use an O2 analyzer described in § 1065.280 for this test, you may use purified N2 to detect a leak. To avoid misleading results from this test, we recommend using only analyzers that have a repeatability of 0.5% or better at the reference gas concentration used for this test. Perform a vacuum-side leak test as follows:

(3) Route overflow reference gas to the inlet of the sample probe or at a tee fitting in the transfer line near the exit of the probe. You may use a valve upstream of the overflow fitting to prevent overflow of reference gas out of the inlet of the probe, but you must then provide an overflow vent in the overflow supply line.

(4) Verify that the measured overflow reference gas concentration is within ±0.5% of the concentration measured in paragraph (d)(2) of this section. A measured value lower than expected indicates a leak, but a value higher than expected may indicate a problem with the reference gas or the analyzer itself. A measured value higher than expected does not indicate a leak.