5
To ensure the best possible results from servicing, when re-assembling the regulator and
any assemblies within it, ensure that all areas of the components and the regulator body are
cleaned and free from contaminants which may result in failure of the regulator.
6.1. Servicing the LF-301
*Note: fig 1 should be used as a reference for the following set of instructions
6.1.1. Accessing the Main Valve Assembly
To access the Main Valve Assembly (MVA):
i.
With the flats of the Regulator Body (1) secured in a vice, loosen and remove the
Bonnet (15) using a 47mm wrench ensuring that the Hand Wheel (17) is fully
wound anti clock wise
(*Ref. 6.1.2)
ii.
Remove the 10mm Ball Bearing (9), Upper Spring Rest (8) and Load Spring (24)
iii.
Using needle nosed pliers, remove the Lower Spring Rest (5), then remove the
Sensor Assembly (6, 7)
iv.
The Seat Nut (4) can then be removed using a 12mm socket
v.
Remove the Main Valve (2, 21) and Main Valve Spring (3) from the assembly
vi.
Visually inspect the seat nut and soft seat (7) for damage under a microscope
vii.
Replace the Main Valve Spring (3) and Main Valve (2, 21) and place into the
Regulator Body (1)
viii.
Replace Seat Nut (4) fitted with new 5x1 mm O-ring (18) taking care not to
damage its sealing face against the tip of the valve
ix.
Replace the O-rings (13, 14, 15, 17) around the Sensor (7) and Sensor Holder (6)
x.
Position the Sensor (7) into the Sensor Holder (6) and then place the assembly
into the Regulator Body (1)
xi.
Replace the O-ring (16) around the Lower Spring Rest (5) and then place into the
Sensor Holder (6)
xii.
Position the Load Spring (24) around the Lower Spring Rest (5) and place the
Upper Spring Rest (8) and 10mm Ball Bearing (9) to the assembly
xiii.
Screw the Bonnet (10) onto the assembly and using a torque wrench with a
47mm open ended attachment, tighten to 90Nm
It is recommended that all parts in the repair kits are used. Any defect parts removed during
the service should be disposed of. Parts should be kept clean in line with media
requirements. Following re-assembly of the regulator, pressure tests should be made to
both the inlet and outlet side of the regulator, to ensure there is no internal or external
leakage across the regulator.
To ensure that the main valve assembly has been correctly and effectively installed it may
be required to perform the appropriate seat leak test as per ANSI/FCI 70-2.
