Jordan Valve Mark 695 Series - Piloted Tank Blanketing Regulator - Manual (Page 2)

•
NEVER reduce the pipe size on the valve outlet to the
tank. This line must always be as large as the valve
size, or one pipe size larger to assure it does not act
as a restriction.
•
Any downstream isolation valve after the regulator
must be a full port type. The isolation valve cannot
act as a restriction.
•
The sensing line must be a minimum of 3/8” tube.
•
A sensing line isolation valve is recommended Again,
must be full ported.
•
Slope the sensing line to the sensing port on the
tank.
•
Keep the sensing line as short and straight as
possible.
•
For each 10 feet of sensing line, increase the tube by
1/8”. (Especially important on the blanket pressures
of less than 5 inches of water column).
•
Keep the sensing port on the tank as far removed as
possible from the downstream pipe outlet going into
the tank.
Start-Up
With the inlet, and bypass shutoff valves closed,
and no pressure in the downstream line:
1. Slowly open the inlet valve just enough to start
flow through the valve. Observe the tank pressure
gauge. Increase the downstream pressure slowly by
gradually opening the inlet valve.
2. Do not fully open the inlet valve until you are sure that
the regulator has control of the system. Usually, the
handwheel on the inlet valve will turn freely when this
is achieved.
3. To change the controlled pressure, adjust the set
screw (25), and secure with the jam nut (26), and the
closing cap (12).
Trouble Shooting
The first step in troubleshooting a piloted pressure
regulator is to classify the action of the controlled
pressure into one of the following categories:
A. Under Pressure: Controlled pressure too low; not
enough flow or no flow through valve.
B. Over Pressure: Valve will not close or controlled
pressure increases after valve closes.
C. Pressure Fluctuates: Controlled pressure rises and
falls, will not settle out under low loads.
The next step is to determine what could cause the
trouble. The third step is to locate and remedy the cause
by the process of elimination. Make no assumptions and
check the easy ones first. The guide below lists the
controlled pressure action, common causes and
procedure for checking each cause.
Controlled pressure action UNDER PRESSURE:
•
Valve undersized for application. Check capacity
required and valve capacity. As described in API-
2000.
•
Line strainer screen clogged. Blow down strainers or
visually check that they are clear.
•
Incorrect setting on range spring. Vary the setting
and check response.
•
Main valve diaphragm or balance diaphragm
ruptured. See section on valve maintenance.
•
Malfunction of other piping components. Check
for leaking safety valves, inadvertently opened or
closed valves.
Controlled pressure action OVER PRESSURE:
•
Incorrect setting on range spring. Vary the setting
and check response.
•
Main valve seats leaking. Close inlet shut-off valve,
allow downstream pressure to bleed off, close outlet
valve and remove loading pressure tubing. Back out
adjusting screw on valve until free. Crack open inlet
shut-off valve - if the fluid issues from the main valve
port, the main valve seats are leaking.
•
By-pass shut-off leaking. During period of leakage
close outlet shut-off valve, observe downstream
pressure gauge
•
Under certain circumstances, the vent valve may be
open when the tank is not being filled. This may not
be caused by an inability to control or seat leakage.
The tank may be “outbreathing” due to increases
in the temperature of the gas or contents inside the
tank.
Controlled Pressure Fluctuates:
•
Valve oversized. Check capacity required and valve
capacity per API 2000.
Main Valve
Note: All work to the main valve can be accomplished
in-line. The only reason to remove the valve is if
the location makes it too difficult to work on the
regulator.
Mark 695 Series Tank Blanketing Valve
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