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ACE95 Series
Shutdown
Installation arrangements vary, but in any installation it
is important to open and close valves slowly and to
close the upstream shut-off valve first when shutting
down the system.
Diagnostics
If a diagnostics pressure gauge was not
ordered with the unit, a pressure gauge
must be installed in the diagnostic port to
perform diagnostic analysis.
Diagnostics are an optional feature of the ACE95
Series Tank Blanketing valves that aid in evaluating
valve operation. The diagnostic analysis relies on the
relationship of pilot pressure and pressure in the main
valve chambers (see figure 3). The basic relationships
are as follows:
Table 2. Diagnostic Analysis Pressure Ranges
D
A I
G
N
O
S
T
C I
P (
R
E
S
S
U
R
E
C
H
A
M
B
E
) R
E
q
u
l a
o t
n i
t e l
u s
p
p
y l
r p
s e
u s
e r
S
g i l
h
y l t
b
e
o l
w
n i
t e l
u s
p
p
y l
r p
s e
u s
e r
W
l l e
b
e
o l
w
n i
t e l
u s
p
p
y l
r p
s e
u s
e r
In order to evaluate a valve, examine the valve name-
plate to determine the Cv and inlet pressure range main
valve spring. The inlet pressure gauge indicates actual
pressure supplied to the valve.
Follow these steps and refer to the diagnostics tables
on the following pages to evaluate a valve under actual
operating conditions:
1. Select the table (tables 3 through 8) that corre-
sponds to the Cv and inlet pressure range of your
valve.
2. Determine the actual valve operating inlet pressure
in the first column of the diagnostics table.
3. In the second column of the table, determine the
pressure of the pilot as it opens.
6
Note
S
T
A
T
U
S
i P
t o l
a
n
d
m
a
n i
a v
v l
s e
a
e r
c
o l
a T
k n
t a
r o
a
b
o
e v
s
t e
p
e r
s s
i P
t o l
v
l a
e v
u s
p
i l p
s e
g
s a
o t
a t
a T
k n
r p
s e
u s
e r
s i
u j
t s
b
e
o l
w
p
e r
s s
r u
. e
i P
t o l
a
n
d
m
a
n i
a v
v l
s e
a
e r
b
u s
p
p
y l
n i
g
g
s a
o t
h t
e
a t
n
. k
a T
r p
s e
u s
e r
s i
b
e
o l
w
s
t e
p
o
n i
4. Determine the diagnostic pressure for the start to
open pressure of the main valve in the third column.
5. The fourth column displays the diagnostic pressure
for the full open pressure of the main valve.
There are four pressures involved in evaluating a valve:
actual inlet pressure, pressure to start opening pilot
valve, pressure to start opening main valve, and
pressure to fully open main valve.
Actual Inlet Pressure: The gas pressure supplied to
the inlet of the valve. This is the maximum diagnostic
pressure.
Pressure to Start Opening Pilot Valve: The diagnostic
pressure drops to this value as the valve senses
decreasing tank pressure. The main valve remains
closed at this pressure.
Pressure to Start Opening Main Valve: The diagnostic
pressure drops to this level as the tank pressure
decreases and reaches the valve set point. The pilot is
fully open at this pressure.
Pressure to Fully Open Main Valve: At this point, both
the main valve and pilot valve are fully open and
supplying gas to the tank.
Maintenance
e s
. d
r u
. e
Valve parts are subject to normal wear and must be
n
. k
inspected and replaced as necessary. The frequency of
s
t e
inspection and replacement of parts depends on the
severity of service conditions and the requirements of
o
h t
local, state, and federal regulations. Due to the care
k n
Fisher Controls takes in meeting all manufacturing
. t
requirements, use only replacement parts manufactured
or furnished by Fisher Controls.
All O-rings, gaskets, and seals should be lubricated
with a good grade of general purpose lubricant and
installed gently rather than forced into position. Ap-
proved lubricant, sealant, and adhesive are as follows:
Lubricant: Dow Corning
Sealant: Loctite
Adhesive: Loctite
Be certain that nameplates are updated to accurately
indicate any field changes in equipment, materials,
service conditions, or pressure settings.
111
PST #592, Teflon
Tape
#222
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