Det-Tronics PIR9400 PointWatch Infrared Hydrocarbon Gas Detector User Manual

Page 21

95-8440

9.3

4. Connect the calibration gas canister, valve and

tubing to the direct input nozzle as shown in either
Figure

(aluminum model) or Figure

(stainless

steel model) depending on the method used.

5. Apply

50%

LFL calibration gas to the detector.

This is accomplished by opening the valve on the
calibration gas canister (see Figure

or Figure

2.5

liter per minute flow rate is recommended.

– The LED will continue flashing

– The current output will increase proportionally as

the gas concentration increases.

6. The detector will automatically accept the span

calibration when the detected gas level is stable
(typically

minutes).

After successful span calibration:

– The LED will turn off steady

– The current will lock in steadily at

12.0

mA,

indicating a successful span calibration.

Proceed to step

If for any reason a successful calibration is not

accomplished within

minutes, a calibration fault

will occur:

– The LED will turn off

– The current output will drop to 1.6 mA.

Turn off the gas, then reset the detector by cycling

power to the detector or by holding the Cal Magnet

near the Cal Switch. Begin the calibration sequence

again at step

7. After successful calibration, close the valve on

the calibration gas canister, remove the flexible

tube from the calibration nozzle and replace the

nozzle cap. If the calibration wind shield was used,

remove it from the detector. After the detector

output falls below

45%

LFL, the current loop

will unlock and will track the declining gas

concentration back to

mA.

iMPoRtant

The calibration ports must be capped to prevent
dirt and water from entering the direct path into the
optics. Failure to protect the optics can result in
a fouled optics fault. If a permanent gas delivery
system is used, the delivery tube must be plugged
when not in use.

MAINTENANCE

The PointWatch Detector requires less routine

maintenance than other combustible gas detectors.

This is accomplished through its design that allows no

undisclosed internal failures, and an optics protection

system that is extremely resistant to fouling by external

contamination. The most significant benefit of this design

is reduced calibration requirements. When installed

and used per the manufacturer’s recommendations,
the Model PIR

9400

Detector does not require routine

calibration, although an annual calibration inspection

is recommended as a good practice. More frequent

calibrations may be performed at the discretion of the

user without adverse impact.

Other recommended maintenance practices include

periodic visual inspections of the sensor and/or weather

protection system. External contaminants and/or debris,

if allowed to accumulate, can reduce sensitivity by

physically blocking vapor access to the sensor. Common

examples include plastic bags, litter, heavy oil and tar,

paint, mud, and snow. This simple visual inspection of

all gas sensors is a good idea, especially for outdoor

installations.

In the unlikely event that the PIR

9400

indicates a

fouled optics condition, it is possible to disassemble

and clean the optics. However, it is recommended that

a spare device be kept on hand to enable complete

exchange of the electronics/optics module in the field,

enabling the disassembly and cleaning operation to

be performed in a clean lab environment.

iMPoRtant MaintEnanCE notES

• use only low vapor pressure silicone grease when

lubricating threads on the PointWatch Detector
and associated termination box. Do not get this
grease on the optics of the detector. A suitable grease
is listed in the “Spare Parts” section at the end of this
manual. Do not use Hydrocarbon-based grease.

Doing so will emit hydrocarbon vapors that will be
measured by the detector, resulting in inaccurate gas
level readings.

• In applications where both PIR

9400

and catalytic

type sensors are used, ensure that the silicone
grease used to lubricate the detector threads does
not come into contact with the catalytic sensors or
poisoning of the catalytic sensors will result. It is
strongly recommended that maintenance personnel
wash their hands between handling the two types of
sensors.