Reference Manual - IARC Screening Group

Troubleshooting with the Cryotherapy SystemTable E-1. Following-Up on Commonly Encountered Problems (continued)PROBLEM4. Gas leaks from theregulator.5. When the gas isturned on, thepressure gaugeneedle moves intothe red-shaded area.6. When the gas isturned on, thepressure gaugeneedle is in theyellow-shaded area(or at or below thegas pressureindication line in thegreen-shaded area).7. When turning on thegas from a newcylinder for the firsttime, there is a loudnoise and gasescapes loudly fromthe safety valve onthe regulator. Afterthis, the cryotherapyunit will not workand gas continues toescape.(table continued on next page)POSSIBLEEXPLANATIONValves in the regulatorare jammed or worn.The gas pressure in thecylinder is too high.The gas pressure in thecylinder is too low.The gas pressure in thecylinder is too high; therupture disk in the safetyvalve broke to releasepressure and preventdamage to thecryotherapy system.APPROPRIATE ACTIONReturn the system to the manufacturer.Vent the cylinder as follows:• Close the main cylinder valve.• Slowly disconnect the regulator from the cylinder torelease the gas in the hose.• Ensure that the main cylinder valve is not pointingtoward anyone.• Slowly open the main cylinder valve just until youcan hear gas escaping. Let a small stream of gasescape for 8 to 10 seconds.• Close the cylinder valve.• Reattach the regulator to the cylinder connector(Figure D-3, page D-3).• Open the main cylinder valve again. If the pressure is still too high, repeat theprocedure.Replace the cylinder with a full one before proceeding.Close the main cylinder valve. Remove the regulator andvent the cylinder, as recommended for Problem 5(above). Then replace the broken rupture disk-nut with anew one as follows:• Using a crescent wrench, remove only the end part ofthe brass safety valve—the hexagonal nut with thetwo holes in the sides (i.e., the rupture disk-nut,which includes a small rubber O-ring).• Do not remove the entire brass fitting from the bodyof the regulator.Note: Two crescent wrenches may be required toremove the brass nut, one to prevent the part that isnearest to the regulator from turning and another toremove the end part.• Dispose of the old rupture disk-nut.• Install the new rupture disk-nut (Wallach Item#400285). Make sure the small rubber O-ring is onthe replacement rupture disk-nut.• Tighten the rupture disk onto the safety valve.E-2 Cervical Cancer Prevention Guidelines for Low-Resource Settings