WatchGas NEO Service Manual page 8

D e t e c t i o n D e t e c t i o n
the rise in pump current value, shown in the upper right. The unblocked pump current is typically
about 100-200 when set to high flow and 200-350 when set to low flow and the blocked pump cur-
rent typically rises to 500 or above. Set the stall threshold about 50-100 units above the unblocked
pump reading, but lower than the blocked pump reading.
NOTE: For NEO Benz MP186, set the stall threshold with an open (used) tube in the holder to avoid
a stall alarm when a tube is inserted for benzene measurements.
4. If the pump still gives low flow (or little strain when flow is blocked), clean the pump gasket as des-
cribed below:
Remove the sensor cap and boot
bracket (2-mm Allen wrench)
Unplug the PID sensor connector
to the circuit board
NEO Photoionization Detector
Peel off the rubber boot. Re-
move 6 housing screws (2-mm
Allen wrench)
Unplug the pump connector to
the circuit board
Remove the 2 screws holding
down the circuit board (Philips
head)
Unscrew the single screw hol-
ding down the pump
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Service Manual