A. When three sensors are out of agreement on the Shearwater Petrel controller, the solenoid will not fire. You will see a message “Voting Logic Failed.” You should bail to open circuit. A diluent flush may confirm which (if any) of the sensors is working properly in the event that you have a long transit out of an overhead environment and are concerned about the volume of open circuit gas available to you. In that case you could theoretically run the unit manually on one working sensor. However, if two of the rogue sensors get close to each other you should be aware that the voting logic may reactivate the solenoid based on two similar bad sensors. Lowering the set point is a good idea, but the best solution is to use open circuit bailout or SCR as a gas extender. Your sensors can’t be trusted.
Jill Heinerth has created a free new video resource for users of the Hollis PRISM2 Rebreather Shearwater Heads Up Display (HUD). View here on YouTube.