Oldham SV 4B - Adjusting the Gas Alarm Thresholds

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4.4.1. Adjusting the "gas alarm" thresholds
Using a "reference gas kit" (gas cylinder + pressure regulator, etc.), inject the reference gas with a
content level higher than the first threshold desired. (For example, threshold 1 will be 20% LEL, so
a minimum of 25% LEL should be injected).
Adjust the alarm potentiometer (item 1, Fig. 7) to trigger the first threshold (AL1): the red LED
(AL1) flashes (for 7 seconds) and then remains on in steady mode, trip the corresponding alarm
relay.
If you stop at this point, alarm 2 will be set to twice the level of alarm 1.
If you continue until alarm 2 is triggered: alarm 1 will be set to half the level of alarm 2.
FIGURE 7
item 3
item 1
item 2
item 4
MV
item 5