Honeywell Midas, User Manual

Page: 76 / 160

Midas
®
Gas Detector
8-3
8.1 Sensor Cartridge Replacement
Honeywell Analytics recommends that the sensor
cartridge be replaced without power to the Midas
®
unit. If fitting a sensor cartridge to a unit that is
powered, please refer to Section 7.4.3 to inhibit the
detector’s outputs.
8.1.1 Sensor Cartridge Fitting/Replace-
ment
1. Unscrew the thumbscrew located on the
front panel and remove the cover by pulling
it forwards off the main chassis (see Diagram
27).
2. Ensure the power switch on the terminal
module is in the off position.
3. Remove the old sensor cartridge from the unit
(if fitted) by unclipping the two sensor cartridge
locking
tabs located either side of the sensor cartridge
and using them to firmly pull the sensor
cartridge out
(see diagram 23).
4. Fit the new sensor cartridge by aligning the
pins at the top of the sensor cartridge with the
socket in the sensor cartridge chamber.
5. Carefully push the sensor cartridge into the
sensor cartridge chamber until fully home and
lock in place using the tabs either side of the
sensor cartridge (see diagram 24).
6. Switch the power switch on the terminal
module to the ‘on’ position.
7. Refit the detector’s cover by aligning the
slots either side with the locating tabs on the
mounting bracket assembly and pushing the
cover horizontally until home. Tighten the
thumbscrew located on the front panel (see
diagram 25).
8. Confirm that the LCD messages “LOAd” and
“WArm” are replaced by a zero concentration
display. Confirm that the yellow fault LED is
off.
Note
If replacing a sensor cartridge with a different
gas type sensor cartridge the display will
scroll the message ‘ChAngE gAS?’ If you are
changing the sensor cartridge gas type press
‘
3
’ to accept. If not, fit the correct sensor
cartridge. The pass code (if set) must be
entered to change sensor cartridge gas type.
To set the correct gas for a multi gas type
sensor cartridge refer to Section 7.2.2 .
Diagram 8-1. Removing detector cover
REMOVING COVER
mounting
bracket
chassis
cover
loosen
midas
Gas Senso
r Cartridge
NITROGEN
TRIFLUORID
E NF3
PN : MIDAS-
S-HFX
SN : 0234456670
Use by : 0
7-09-2006
Diagram 8-2. Removing sensor cartridge
midas
Gas Sensor C
artridge
NITROGEN T
RIFLUORIDE
NF3
PN : MIDAS-S-H
FX
SN : 0234456
670
Use by : 07-09-
2006 zellwege
r analytics
sensor