Groth 1402 - Manual (Page 4)

1402revb.doc 3
Trouble Shooting
Any vapor emitted from the pilot should
be vented through the fitting [7] on the
spring bonnet.
There should be no emission when the
sensed tank pressure is less than 80% of
set pressure or greater than 110% of set
pressure.
The valve actuator upper dome should
receive tank pressure or vacuum or
independent supply pressure when the
sensed tank pressure is less than set
pressure. The lower dome should be
exposed to tank pressure when sensed
pressure is greater than 110% of set
pressure.
These conditions may be observed while
the valve is in service or during shop
testing. See test procedure on page 3. If
any of these conditions are not met, the
pilot must be disassembled, cleaned and
inspected. Replace all soft goods,
assemble and test according to the
following procedures.
Disassembly
Disconnect pilot at sense, upper dome and
lower dome ports. Remove tank pressure
supply tube. Invert the pilot and remove
hex bolts [22], lower actuator housing
[27], gasket [25], diaphragm [26] and
support plate sub-assembly. If the
diaphragm is damaged, it may be
replaced and the pilot may be tested
without further disassembly.
If further disassembly is required, remove
hex bolts [20] and upper actuator housing
[21].
Then invert pilot and remove the
adjustment screw cap [1], loosen the jam
nut [3], and back out the adjusting screw
[2] to release spring tension. Remove hex
bolts [8], the spring bonnet sub-assembly,
spring buttons [5 & 9], spring [6] and
retainer plate [10]. Remove the spool/seat
sub-assembly. This will require some
force to slide the O-Rings from the body.
Remove the upper and lower seat inserts
[13] from the spool [12]. Remove one
spool O-Ring [15], the seat [16] and the
other O-Ring [15]. Thoroughly clean and
inspect all parts. All seating surfaces
should be sharp but free of burrs or nicks.
Replace all O-Rings.
Note: Consult factory for soft goods kit
replacement for any valves sold prior
to March 2000.
Assembly
Lightly lubricate all O-Rings, removing
any excess lubricant. Slide the seat [16]
onto the spool [12] before installing the
final O-Ring [15]. Then position the seat
inserts and all O-Rings and slide the
spool/seat sub-assembly into the body.
Verify that the spool moves freely inside
the seats.
Position the retainer plate [10], the spring
[6] and spring buttons [5 & 9] and the
spring bonnet sub-assembly. Insert the
hex bolts and tighten uniformly. The thin
plate will be deformed as the bolts are
tightened, firmly clamping the seat inserts
in place. If necessary, remove the vent
fitting [7] to verify that the adjusting screw
is engaged with the upper spring button.
Final screw adjustment will be made after
assembly is complete.
Invert the pilot and position the support
plate sub-assembly, diaphragm [26],
gasket [25] and lower actuator housing
[27]. Insert the hex bolts [22], lock
washers [24] and nuts [23] and tighten
uniformly. Install tank pressure supply
tube. Test and adjust for set pressure
according to the following procedure.
Then tighten the jam nut [3] and replace
the cap [1].
Test Procedure
Connect the pilot as shown in figure 2.
Increase the tank pressure very slowly.
Adjust the set pressure adjustment screw
as required to maintain the following
conditions.