PCM-2 Manual.pdf - Voss Associates

6. Allow the pressure to build up to 0.25 in. of water as indicated by the gas
manager's display. When this pressure has been reached, press and hold
down the gas manager's control knob until the "COUNTERS CLEARED"
message appears and then release the knob. The gas manager wi II then begin
its detector pressurization duty cycle.
7. Wait a minimum of 5 minutes and read the gas counters. Passing duty cycle
test valves for the detectors are as follows:
Large
Medium
Small
1.5% or less
1.0% or less
0.8% or less
A higher value indicates an unacceptable leak rate for the detector.
NOTE:
Detectors which have failed this leak test criteria can often be
remedied by first "sniffing" out the leak(s), while still connected
up to the gas manager, with a P-l 0 gas detector and then correcting
the cause of the leak(s) when identified. Areas of the probe likely to
be subject to leakage are the threaded joints at the quick-connect gas
fittings, the high voltage fitting(s) and the four corners of the probe.
Identify any leaks detected by labeling as such at their location(s).
8. Disconnect the probe from the gas manager test setup by removing the gas
supply hose first and then the gas return hose, Again equalize the probe's
internal pressure by installing an exhausting quick-connect coupling into one
of the probe's gas fittings,
NOTE:
This exhausting quick-connect fitting should remain in the probe
if the probe is to be shipped via land or air as an individual item
(i.e. not installed into a PCM-2 unit) to avoid probe face bursting
due to potential pressure differentials encountered in shipment.
9. Record the detector's leakage test duty cycle on a labeling sticker 011 the back
surface of the detector chamber and route the probe for further assembly into
the PCM-2 or for necessary leakage rework.
10. Repeat the entire leak test procedure for all previously faded probes wh ich have
been reworked for leakage.
10429-A525/PCM-2 Det. Voltage & Leak Test Procedure/Revision/March 1994 6