Doc. 12-4091 - r01 (9/12/12)
PG-61
SERVICE
GUIDE
SUPPORT: TOLL-FREE 888-383-DIVE │ FAX 510-729-5115 │ E-MAIL [email protected]
©
2002 DESIGN
(
2012)
TROUBLESHOOTING
Oxygen sensors are both critical to a rebreather and quite possibly the most sensitive component. With proper
care sensor issues can be greatly reduced or eliminated. Keep a few things in mind when servicing or counseling
your customer's Prism 2 rebreather use.
1. Sensors are expendable, the diver is not.
The sensors from Hollis have a "Do not use after" date printed on the body. They should last around 12 months
of use or 16 months from manufacture, whichever comes first. But regardless of the expected sensor life, they
must be taken out of service whenever they fail to operate .
2. Sensors must acclimate for at least 12 hours after opening their packaging, exposing them to air.
Once opened the sensor's chemical reaction must reach a stable reaction rate before use or Prism 2 calibration.
3. Sensors are sensitive to extreme temperatures.
Storage of Oxygen Sensors below 32° F (0°) or above 100° F (37.8° C) can damage or greatly shorten the life of
the sensor.
4. Sensors are sensitive to impact and shock.
At all times sensors must not be knocked around or mishandled. Sensors should be individually wrapped in bub-
ble wrap when travelling. Alternately, leave the
OXYGEN SENSORS (7)
installed in their
SENSOR HOLDERS (6)
to insulate against shock.
Then carry the
SCRUBBER HEAD (1)
inside the supplied "Blue Box" when travelling
by air, to further insulate the
SCRUBBER HEAD (1)
and
OXYGEN SENSORS (7)
from shock.
5. Touching and contaminating the Teflon membrane face of the sensor can cause reduction in the signal output
or destruction of the sensor. Oils from even freshly washed hands can clog the Sensor Membrane's pores. It is
best to handle the sensor by its plastic sides.
6. Sensors chemically react with a finite amount of oxygen before exhausting their chemical reactivity.
Leaving high PO
2
gas in the Breathing Loop while not diving reduces sensor life. A diver should shut off the
oxygen tank valve and electronics (to avoid constant solenoid activation) when in transport and after the dive day.
The diver should also flush the high oxygen PO
2
gas out of the breathing loop after a sensor calibration and at the
end of the diving day.
7. Electrical connectors can easily be damaged.
Never force or twist the Electrical connectors.
USE ONLY
DeoxIT® Gold GN5 to clean terminals.
8. Mixing brands and aged sensors with new may lead to a functional sensor being voted out.
USE ONLY
Hollis sensors.
DO NOT
mix sensors close to the end of their service life with fresh sensors.
9. Oxygen Sensors may become "millivolt limited".
Validate Oxygen Sensors are not millivolt limited before use.