should also be replaced if any part of it is cracked. Air can leak in through the crack and cause
errors in the readings.
SAMPLE PROBE ASSEMBLY
The probe assembly is a one piece assembly and cannot be taken apart. The tubing used is a
very narrow bore inert polymer which extends from the flanged end to the tip of the probe
assembly. The inert composition prevents O2 adsorption on the internal surface. The internal
tubing volume is small to minimize the volume of sample required to flush out the sensor to
provide an adequate response time. The tip is a male luer fitting which will accept any luer-
hubbed needle or filter. When screwed into the bulkhead fitting, the captive black screw
presses the flanged end tightly against a mating piece, also flanged, which connects to the
inlet port of the O2 sensor.
The probe assembly should be replaced if any part of it is cracked, or if liquid or other
contaminate is visible inside the tubing. Minor kinks in the tubing are generally not a
problem, but severe kinks can impede the sample flow or can develop a crack causing leaks.
To replace, unscrew the black plastic screw from the fitting on the analyzer case. Inspect the
interior of the fitting for any dirt or particles, which might cause a bad seal. Screw in the
plastic screw for the new probe. The threads are easily stripped, so make sure that the screw
is properly aligned before tightening. Turn until finger tight only. Do not use a tool to tighten,
because this can strip the threads.
BATTERY OPERATION AND RE-CHARGING
The Ni-Cd batteries in the 901 require several charge-discharge cycles before reaching full
capacity. During the first 40-50 hours of use, the battery charge will not be optimum but will
improve as the unit is used. To properly condition the batteries, it is important during this
initial period of use to run the unit in the battery mode until the batteries need to be recharged,
as indicated by the LO BATT light.
If left idle for 30 minutes, the unit will shut itself off to conserve power. When the battery is
low, the LOW BATT indicator will be lit, indicating that the batteries need to be re-charged.
The battery cover can be removed if needed by sliding it toward the bottom of the instrument.
The unit will run 8-10 hours before needing recharging. To re-charge the batteries, plug the
external charger module into a standard 115 Vac outlet and connect the plug from the charger
to the jack located on the side of the 901. A full charge requires 8-10 hours of charging time.
The unit will operate with four alkaline batteries, which are non-rechargeable. However,
these frequently leak and can corrode the terminals with long-term use. The unit is designed
to operate with the batteries supplied.
Excessive charging can reduce the useful lifetime of Ni-Cad batteries. Unplug the unit from
the charger when charging is complete. Do not operate the unit with the charger plugged in all
the time. At least every 2-3 days, run the unit on battery power only.
Coffee Laboratory 589 Rappahannock Drive White Stone Va 22578 TEL (804) 435-5522
www.coffeelabequipment.com
