(c) Amber Warn Light. The amber warn light comes on
when a combustible gas condition exceeding the low alarm settng
exists at the remote detector, or when the alarm test switch ((e)
below) has been actuated.
(d) Red Alarm Light. The red alarm light comes on
when a combustible gas condition exceeding the high alarm setting
exists at the remote detector, or when the alarm test switch has been
(e) Alarm Test Switch. The alarm test switch is a
momentary contact pushbutton switch incorporated with the warn light.
When it is depressed electrically, there is a simulation of an alarm
level of gas concentration at the remote detector. This switch
provides a functional check of the analyzer and remote alarm circuit.
(f) Alarm Reset Switch. The alarm reset switch is a
momentary contact pushbutton switch located on the cabinet door.
Depressing the switch deactivates the holding circuits of the alarm
and warning relays if a safe gas condition has been restored at the
remote detector. If a safe condition does not exist, the unit cannot
(g) Indicator Meter. The indicator meter shows the
concentration of combustible gas at the detection point.
(h) Terminals. Terminals are accessible when the
front panel is open and the printed circuit card is removed. Term-
inals are provided for incoming power, remote detector leads, alarm
and failure devices, and for external warning devices and recorder,
(3) Alarm System Detector. The detector consists of the
body, detector element and shield assembly. The body houses the
detector element and holds the shield in place. The element is a
replaceable gas sensing unit that plugs directly into the body when
the shield is removed. The shield assembly consists of a shield and
a flashback screen, which prevents ignition of combustible gases.
The detector, which is explosion proof, is located in an area where
flammable gas or vapor may be released. It is mounted on a 3/4 inch
conduit that leads to the cabinet assembly; the detector lead enters
the cabinet through 3/4 inch conduit fittings.
(4) Placing the Alarm System in Operation.
(a) Initial Startup Procedures.
1. Turn on the power (the pilot light should
come on). A 45-second delay disables the alarm circuits to permit
instrument warmup. Allow the system to stabilize for 5 minutes.
2. Make sure that the remote detector is in a
combustible gas-free area. The area surrounding the detector can be
checked by using a portable combustible gas indicator.