10 INS/ANAINST/007-EN Rev. B | Endura AZ40 | Sensor assembly | Orifice and seals kit
8.3.2 Replacing CO sensor assembly gaskets
Referring to Fig. 8.4, page 11:
1. Remove insulation Asurrounding COe block Bby
loosening insulation retainers Cand sliding the insulation
up off the block over COe sensor wires Dor, optionally,
remove insulation retainers Cand unwrap the insulation
from around COe block assembly B.
2. Use a small crosshead screwdriver to remove 2 sensor
clamp plate retaining screws / washers Eand lift CO
block insulator Fand sensor clamp plate Gup with CO
sensor Hin place.
3. Take care not to disturb COe heater wires Iand use a
small flat-bladed screwdriver to remove thermocouple
retaining screw J(complete with attached washer K)
and carefully remove COe block thermocouple L. Retain
thermocouple for re-use.
4. Use a 3/16 in. allen key (wrench) to loosen and remove 2
COe block retaining screws / washers M.
5. Remove COe block N, preheater O, isolator P, block
gasket Qand isolator gaskets Rfrom flange manifold
S.
6. Remove dilution air restrictor Tfrom isolator P.
7. Carefully remove any gasket material from all surfaces –
a single-edged razor blade can be used.
8. Fit dilution air resrictor Tto isolator P.
9. Assemble items N, Q, O, Rand Pin the correct
order, ensuring the new gaskets Qand Rare aligned
correctly.
10. Apply a light coating of an anti-seize compound (suitable
for temperatures up to 200 °C [392 °F]) to the threaded
portions of COe block retaining screws M.
11. Position the COe block assembly on manifold Sand use
a 3/16 in. allen key (wrench) to fit and tighten 2 COe block
retaining screws / washers M. Tighten the screws
alternately, checking gasket / block alignment during
tightening.
12. Apply a light coating of an anti-seize compound (suitable
for temperatures up to 200 °C [392 °F]) to the threaded
portion of thermocouple retaining screw J.
13. Locate COe block thermocouple Lensuring it passes all
the way into the thermocouple hole and use a small
flat-bladed screwdriver to fit thermocouple retaining screw
J(complete with attached washer K).
14. Re-fit COe block insulation Ain the reverse order of
removal.
15. Apply a light coating of an anti-seize compound (suitable
for temperatures up to 200 °C [392 °F]) to sensor clamp
plate retaining screws E.
16. Position CO block insulator Fwith sensor clamp plate
Gand CO sensor Hin place over COe block Nand
use a small crosshead screwdriver to secure 2 sensor
clamp plate retaining screws Eto COe block N.
17. Refit the O2sensor by reversing the removal procedure –
refer to Section 8.3.1, page 9.
18. Refit the sensor cover – refer to Section 8.2.2, page 8.
19. Refit the probe, exhaust filter, adaptor flange (if fitted) by
reversing the removal procedure – refer to Section 8.1,
page 8.
20. Prepare the sensor for operation by reversing the
shutdown / removal / isolation procedures –
refer to Sections 5 and 4 (pages 4, 4).
CAUTION – Damage to equipment
Appropriate PPE (gloves / goggles) must be worn
when performing this step. The heater block
insulation material is fragile and becomes brittle
after continuous operation. When sliding insulation
away from the CO block or removing it, handle
carefully.
CAUTION – Damage to equipment
The CO sensor is fragile. The sensor elements
should be protected to ensure no damage or
contamination occurs during this procedure.
CAUTION – Damage to equipment
The thermocouple is fragile and brittle. Handle with
care.
CAUTION – Damage to equipment
When removing gasket material do not scratch the
surfaces as damage to any internal / mating face
may affect sensor performance.
CAUTION – Damage to equipment
Alignment of the gaskets is critical to ensure a
leak-free assembly. Double-check gaskets / blocks
alignment before securing the COe block to the
manifold.
CAUTION – Damage to equipment
Do not allow anti-seize compound to contaminate
any part of the CO sensor or other local
component(s).
CAUTION – Damage to equipment
– The thermocouple is fragile and brittle. Do not
bend or break the thermocouple tip.
– When refitting the thermocouple, ensure the
thermocouple wiring is clear of screw J/
attached washer Kwhile tightening to
prevent fraying / nicking of wires.
CAUTION – Damage to equipment
When re-commissioning the sensor, check the
temperature of the CO block to ensure it is reading
correctly. Perform a manual calibration.
