CAIRE 1000B Provider Technical Maunal page 46

Personal Ambulatory Oxygen System Provider Technical Manual
2. Unscrew the wing nut that hold the HEPA filter.
Figure 23: Wing Nut.
3. Unscrew the Clear HEPA filter and discard Filter & small O-Ring.
Figure 24: Unscrewing the HEPA Filter.
4. Install the new small O-ring and HEPA filter.
Figure 25 Installing the new HEPA Filter.
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