7
6.1.2. Accessing the Domed Sensor Assembly (SA)
The loading mechanism and vent seat for the LF-690 can be accessed from the top of the
regulator. Ensure the spring is de-compressed by rotating the hand wheel fully anti-
clockwise and follow the instructions below:
i.
Remove the securing grub screw (20) from the regulator body (1).
ii.
Unscrew the pan screw (36) and remove the name plate (33) from the hand
wheel (35).
iii.
Using a 24mm socket, unscrew the locknut (34) and remove the hand wheel (35)
from the adjusting screw (18).
iv.
With the regulator secured up-right in a vice, remove the bonnet (31) by using a
torque wrench or equivalent with 47mm open end.
v.
Un-screw and lift the top works from the assembly, inclusive of the bonnet (31),
load spring (15), adjusting mechanism (16, 17, 18 & 19) and lower spring rest (12)
from the body.
vi.
The sensor assembly (10, 11, 13 & 14) can be removed from the body by using an
M5 bolt and pliers.
vii.
If necessary, the baffle plate (3) and connector (8) can be withdrawn. Inspect the
connector for damage and replace if required.
viii.
The vent seat (14) can be accessed by removing the sensor (10) from the sensor
holder (11) and gripping the sensor firmly in a vice with the vent seat nut (13)
facing upwards.
ix.
The vent seat nut (13) can be removed using a 10mm open ended spanner and
the vent seat (14) can then be removed from the sensor (10) along with the 9mm
x 1mm ‘O’ ring (22).
x.
Inspect the vent seat (14) for damage and replace if necessary.
xi.
Replace all ‘O’ rings (21
, 22, 23, 24, 29, 30 & 32) located on the sensor (10) and
sensor holder (11) prior to reassembly, ensuring adequate lubrication is used.
xii.
Place the connector (8) into the baffle plate (3) and locate into the regulator
body, taking care not to damage the sealing edge of the connector.
xiii.
After reassembling the sensor (10) and holder (11), place the assembly into the
regulator body (1) ensuring that it is firmly in place.
xiv.
Remove the M5 screw from the sensor holder if used.
xv.
Screw the top works onto the regulator body and using a torque wrench, tighten
to 120Nm.
xvi.
Tighten the securing grub screw (20) against the bonnet (31).
xvii.
The hand wheel (35) can now be secured on to the adjusting screw (18) using the
locknut (34).
xviii.
The name plate (33) can then be secured using the pan screw (36).
It is recommended that all parts in the repair kits are used. Any defect parts removed during
the service should be disposed of.
Replacement
‘O’ rings
should be lubricated with suitable non-hydrocarbon grease such as
Krytox GPL 205.
