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4. Pneumatics Failure
5. Failure to Detect a
Leak or Suspected Low
Sensitivity
If there is no DC voltage, turn off the
monitor and remove one device at a time from the
DC power circuit. The 24 vdc relays can be
removed from the relay socket. The control board
can be disconnected at the input terminal on the
board. The solenoid valves can be disconnected
at TB1-6. Note: the power supply must have a
load to operate, so each item must be
disconnected, then tested and replaced.
b) If there is DC voltage on R53, check the 24 vdc
terminals on the alarm relays. Using the wire-list
from the previous section, isolate the fault to a
wiring problem.
a) Check that the diaphragm pump is operating
and replace if it has failed.
b) Check that the tubing inside the monitor has not
come loose from any fitting, or become kinked at
any point.
c) Check that the orifice or tube end filter have not
become clogged or restricted.
d) Check that the tubes connected to the sample
air inlet and fresh air inlet have not become
clogged or restricted.
e) Check that the solenoid valves are switching.
Verify that the lights labeled “RLY5” and “RLY6”
are switching on and off. Temporarily block the air
inlet and listen for the diaphragm pump to draw a
vacuum. If the pump does not change tone, and is
known to work, the valve is not switching.
a) Alarm lights are on, but external alarm devices
are not actuated. Repeat the “Integration with
External Devices” from the Final test portion of this
manual.
b) Alarm light is not on, but a leak is suspected.
Verify that the alarm settings are not set too high.
Summary of Contents for IR-SNIF-1
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