Jordan Valve Mark 5108 User Manual

I & M Mark 5108 Series

3170 Wasson Road • Cincinnati, OH 45209
Phone [phone] • Fax [phone] (f)
[e-mail] • www.jordanvalve.com

Warning: Jordan Valve Control Valves must only be used, installed and repaired in accordance with these Installa­tion & Maintenance Instructions. Observe all applicable public and company codes and regulations. In the event
of leakage or other malfunction, call a qualified service person; continued operation may cause system failure or
a general hazard. Before servicing any valve, disconnect, shut off, or bypass all pressurized fluid. Before disassem­bling a valve, be sure to release all spring tension.

IntroductIon

The Mark 5108 may be generically described as
a back pressure control valve, i.e., it controls the
pressure at its inlet. With this type of control, the
Mark 5108 may be employed in two different ways:

1. As a Pressure Relief Valve. Here the 5108
is installed on a bypass from a main line. It
opens to relieve any pressure above its set
point.

2. As a Pressure Sustaining Valve. Here the
Mark 5108 is installed in the main line itself. It
functions to control the incoming pressure at
the set point, or more commonly, to prevent
the pressure from falling below a
predetermined minimum. For example, it may
be installed on the discharge of a pump to
ensure that the pump remains "on its curve."

Installation & Maintenance Instructions for the

Mark 5108 Back Pressure Regulating Valve

4. Flow Control Valve, a needle-type valve
which provides adjustable, restricted flow in
one direction, and free flow in the opposite
direction. On the Mark 5108, the flow control
valve is connected as a closing speed
control.

5. The Y-Strainer (standard on water
service valves) or Mark 5123 Inline Strainer
(standard on fuel service valves). The strainer
protects the pilot system from solid
contami nants in the line fluid.

6. Two Ball Valves (standard on water service
valves, optional on fuel service valves), useful
for isolating the pilot system for maintenance
or trouble shooting.

At user option, the 5108 may also be equipped with
the following:

The Mark 5108 consists of the following components,
arranged as shown on the schematic diagram:

1. Basic Control Valve, a hydraulically
operated, diaphragm-actuated, globe or
angle valve which closes with an elastomer-on-
metal seal.

2. Pressure Relief Pilot, a two-way, normally
closed pilot valve which senses up-stream
presure under its diaphragm and balances it
against an adjustable spring load. An increase
in upstream pressure tends to make the pilot
open.

3. Ejector, a simple "tee" fitting with a fixed orifice
in its inlet port. It provides the proper pressure to
the diaphragm chamber of the main valve
depending on the position of the pressure relief
pilot.

1. Visual Indicator.

2. Limit Switch Assembly (includes visual
indicator).

3. Opening Speed Control.

Mark 5108 SerieS Back PreSSure regulating ValVe

theory of operatIon

To understand how the Mark 5108 operates, it is best
to start with the Ejector (3). Due to the orifice in its
upstream port, the ejector creates a pressure drop
proportional to the flow through it. The flow through the
ejector is in turn controlled by the degree of opening of
the Pressure Relief Pilot (2). The wider the pilot opens,
the greater the flow through the ejector and the lower the
pressure downstream of the orifice. Conversely, the more
the pilot closes, the lower the flow through the ejector
and the greater the pressure downstream of the orifice.

Now note that the diaphragm chamber of the Main Valve
(1) is connected to the branch port of the ejector and is
thus downstream of the orifice. Therefore, the pressure in
the diaphragm chamber of the main valve is effectively
controlled by the pressure relief pilot in the manner
described above. As the pilot opens, the diaphragm
pressure decreases and the main valve opens; as the
pilot closes, the diaphragm pressure increases and the
main valve closes.

If the Mark 5108 is installed as a pressure relief valve,
the pressure upstream of the main valve is normally
below the set point of the relief pilot. Therefore, the pilot
is fully closed, and so is the main valve. However, if, for
any reason, the pressure rises above the set point, the
pilot will open, and the main valve will follow in turn. The
net effect is that the main valve will open and control
the pressure at the set point, not allowing it to rise any
further. Once pressure returns to normal, the pilot and
main valve will return to the closed position.

If the Mark 5108 is installed as a pressure sustaining
valve, the pressure upstream of the main valve is
normally above the set point of the relief pilot. Therefore,
the pilot is wide open as is the main valve. However, if
system demand increases to the point that the upstream
pressure tries to fall below the set point, the pilot will
start to close and the main valve will follow, throttling as
required to keep the pressure from falling any further.

InstallatIon

Figure 1 shows a typical installation of an angle pattern
Mark 5108 in pressure service. Here it will relieve the
startup surges of the centrifugal pump, but this time in
pressure sustaining service. Here it will keep a
minimum back pressure on the pump to keep it from
running off the right of its curve in periods of high system
demand. These illustrations are intended only as rough
guides for valve installation, as indeed there are many
other places in a system where the Mark 5108 can be
effectively employed. However, note the use of isolation
valves. While these do not affect the operation of the
5108, they can be extremely useful if the valve needs to
be isolated from the line for maintenance or repair.

For full installation details, the user is referred to the Main
Valve section of this manual.

start- up and adjustments

The following procedures should be followed in the order
presented in order to affect an initial startup of the Mark

5108. Note that the procedure differs somewhat between
a pressure relief valve and a pressure sustaining valve.

Procedure A. Pressure Relief Valve

1. Install a pressure gauge of the proper range
upstream of the Mark 5108. The unused inlet
side port in the main valve body may be
used for this purpose if there is no
convenient location in the upstream piping.

2. Remove the plastic cap from the pressure relief
pilot (2) and loosen the adjusting screw jam nut.
Turn the adjusting screw clockwise to a full stop.

3. Loosen the adjusting screw jam nut on the flow
control valve (4) (closing speed control). Turn
the adjusting screw clockwise to a full stop, then
counterclockwise three full turns.

4. Make sure both pilot system isolation ball valves
(6A and 6B) are open.

5. Start the pump or otherwise start the system
flowing. The main valve at this time should
be fully closed.

6. Carefully loosen a pipe plug in the main valve
bonnet until fluid begins to discharge around
the threads. When only clear fluid (no air)
is discharging, retighten the plug.

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