CSA XLC 325 User manual

XLC 325/425
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1
CSA waterworks line
Upstream pressure sustaining/relief
automatic control valve
with solenoid control
Mod. XLC 325/425

XLC 325/425
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2
Personnel involved in the installation or maintenance of valves should always be alert
to potential emission of water and pipeline material, and take the necessary safety
precautions. Always wear the suitable protection like helmets, gloves, googles, when
dealing and handling hazardous pipelines and valves.
Introduction
This manual will provide you with the information to properly install and maintain CSA automatic
control valves XLC series. The contents and the procedure are intended for technicians in charge
of CSA valves only, prior to a theoretical and practical training by CSA qualified personnel only.
Safety
All safety messages in the instruction manual are flagged with the following symbol meaning
danger, caution and warning. This means and makes reference to procedures that may lead to
equipment and system damage and to severe injury or death for the personnel involved.
Inspection
Your valve XLC series has been packaged to provide protection during shipment, however it can
be damaged during transport. Please carefully inspect the unit for damages or discrepancies with
the order upon arrival and report a claim immediately before unloading the goods.
Parts
Recommended spare parts for each components are listed on the respective assembly drawings
depicted on the following pages. These parts should be stocked to minimize delays in case of
malfunction. All CSA products and spare parts can be supplied by CSA official distributors or
directly from CSA. When ordering spare parts please make reference to the assembly drawing
and identification plate present on the valve.
CSAService
CSA service personnel are highly qualified to maintain and repair all CSA products, CSA also
offers customized training program and consultation services.
For more information please contact CSA or visit the web site www.csasrl.it constantly updated.

XLC 325/425
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Contents
Description - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4
Handling and Storage - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5
Installation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6
Set up - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 7
MSM – Upstream pressure sustaining/relief pilot - - - - - - - - - - - - - - - - - - - - - - - - - - - 9
GR.I.F.O. 3 – 3/8″ PN 25 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 11
Needle valve 3/8" – VS - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 13
A2 Two ways flow accelerator - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 14
Visual position indicator - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
Interventions on the main XLC valve - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 16
Troubleshooting - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 17
Guarantee - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 22

XLC 325/425
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Description
The pilot operated control valve XLC series Mod. 325/425 is designed to automatically sustain and
relief a upstream pressure value, regardless of variation in demand and upstream pressure
fluctuations. Thanks to the solenoid control the valve will be able to close or open, in response to a
signal sent from remote or by an external controller.
PR A
6014-C(N.C.)
6014-D(N.A.)
BPR
2
1
4
56
3
7
10
11
9
8
1
2
3
4
5
6
7
8
9
GJS 450-10 or GJS 500-7
AISI 316
AISI 303
AISI 303
Bronze/AISI 303
AISI 303
AISI 303/316
AISI 316
10
N.
AISI 316
11
Two ways auxiliary valve AISI 303
Three ways solenoid valve Brass
Component Material
Main valve XLC
Isolation valve
Isolation valve
Needle valve
Grifo 3/8"
"MSM" pilot
Position indicator
Pipes
Fittings

XLC 325/425
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Lifting the valve in the wrong way may cause malfunctioning, emission of water
spurts, injuries to the personnel and permanent damages of the valve.
Handling and storage
Lifting the valve improperly may damage it and the equipments around. It is mandatory not to
fasten the valve around the circuit, fittings, pipes, solenoids or position indicators. Valves must be
lifted only by cables, chains, located around the body, through the flanges holes or eyebolts.
During hoisting always consider that the center of mass depends on the circuitry and pilots
installed.
If installation will be delayed place the valve indoors in a secure watertight storage. Should that be
unavailable use a vermin proof rain cover around the valve to keep off rain , mud , humidity. Place
the valve on a solid and well drained surface base to prevent moisture, flood from reaching the
body.

XLC 325/425
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Using the valve with extreme low flow rate and/or excessive differential pressure
conditions may cause pulsations and instability.
Please make reference to the
recommended flow and pressure charts or contact CSA for assistance with the proper
sizing.
Installation
The automatic control valve XLC must be always installed in a horizontal position with the bonnet
upwards. Smaller valves, (up to 150 mm) can be installed in a vertical pipe shouldn’t be
unavoidable. Prior to that consult CSA and specify the orientation in the order. A stable and non
pulsating source of pressure is necessary for the proper performance of CSA control valves,
whose minimum pressure is displayed on the technical brochure and always 0,5 bar on the pilot in
addition to the headloss produced during working conditions.
•Gate valves or other sectioning devices must be installed upstream and downstream of
CSA control valves to allow for maintenance.
•The operating fluid must be free of air, air valves (CSA Mod. FOX 3F AS combination anti-
slam) should be installed downstream and upstream. This to avoid the accumulation of air
pockets during working conditions, allow air discharge during pipe filling and entrance in
case of pipe burst and draining.
•A suitable by-pass should be provided for servicing of the valve without interrupting the
flow. For the by-pass sectioning do not use standard gate valve, likely to get damaged
during modulation, but rely on globe pattern gate valves and/or CSA direct acting pressure
sustaining / relief valves Mod. VSM.
•If not included in the order install pressure gauges upstream and downstream if necessary,
a flow measurement device is always recommended to make sure hydraulic conditions
remain within the values used for sizing.
•A strainer with suitable basket and mesh should be installed ahead of the valve to protect
internal components from debris, particles and foreign material.
•Sufficient space should be provided around the valve for disassembly.
•Check direction of flow and make sure it is according to the marking on the valve’s casting.
•Make sure the flanges and pipes connection are according to the valve’s standard. The
nuts and bolts setting has to be conducted in the proper way, gradual and symmetrical, in
order not to produced additional stress and deformation.
•Make sure the power supply is in accordance with the solenoid valve’s specification and
requirements
•During handling be sure not to damage the glass of the position indicator, if present.

XLC 325/425
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The set up and valve regulation has to be carried out by qualified personnel only, or
directly from CSA service. Improper actions can lead to permanent damages to the
valve, its internal components and system equipments along with possible injuries of
the people involved.
The difference in pressure
generated by the valve during the pressure
sustaining/relief function will produce a thrust proportional to the pressure itself.
Anchorage blocks and way of preventing valve’s movement or shifting need to be
taken into account.
Set up
For the proper set up of XLC 400 Mod. 425 reader is advised to use the following points (rif. picture
1 on page 4).
•Make sure the isolation ball valves of the circuitry (2-3) are fully open with the needle valve
(4) partially open. The latter regulates the intervention time and response of the entire
valve. Keeping it closed will prevent the valve from operating properly , we recommend
user at first to leave it open by ¼ of a turn starting from the fully closed position.
•The valve is at first isolated from the main line as both sectioning devices, upstream and
downstream, are closed.
•Unless a specific setting has been required remove the hood from the pilot (6) and turn the
screw clockwise to increase the spring force in the cover almost completely. The upstream
set pressure depends on the pilot setting and it is proportional to the charge of the spring.
Regulation chart are available on request. Doing so the valve will divert upstream pressure
to the main chamber, closing it completely, as the upstream set point would become higher
than the incoming pressure.
•Slowly operate on the upstream gate valve to open it by 30 %, leaving the downstream
sectioning device completely closed.
•Pressure will enter the valve’s body, circuitry and bonnet pushing down the diaphragm and
mobile block against the obturator and inducing the valve’s closure
•Remove the air entrapped in the bonnet, during the operation, by means of the air release
device located on top of the position indicator (7) leaving it flowing for at least 20 seconds.
•Open completely the upstream gate valve
•Slowly open the downstream gate valve, to a maximum of 40% of the stroke, act on the
spring on the pilot decompressing it (turning it anticlock wise) to generate some flow
through the valve and allow for some time to react, this depends on how big is the system

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Regulations of pilots has to be carried out slowly to avoid unwanted pulsations and
pressure surges. Always leave enough time for the system to balance, in case of
doubts and problems allow for some flow through the by-pass to stabilize the line and
call CSA technical support.
downstream and on the variations in demands.
•Having generated the flow it means that the upstream pressure set point has reached the
incoming pressure value.
•Slowly act on the regulation screw on the pilot (6) turning it clockwise to limit the flow
increasing the upstream pressure to be sustained or anticlockwise to increase the flow
reducing the upstream pressure to be sustained , the variation in pressure depends on the
spring range used, and can vary from 0,47 bar to 0,95 bar per revolution with the most
common springs used. Please consult CSA for more details and for the regulation chart
expressing the setpoint versus the spring compression.
•Once the valve has reached the desired value set the locking nut and place the hood on top
of the pilot. Open the downstream gate valve completely then and check once again the
pressure gauge and the flow meters.
•The unit flow control device GR.I.F.O. (5) is exclusive from CSA and contains needle
valves, filter and check valves used for the proper valve’s stability and regulation. If present
do never change the settings before consulting with CSA technical support.
•The solenoid (9) is placed on top of a 2 ways flow accelerator (8) to allow for opening and
closing by means of the incoming pressure, obtain through signals. Valve can be supplied
normally open or closed depending on the flow and valve’s position in absence of power
supply.
•Needle valve (4) is used to adjust the main valve response time, the mode ir is throttle the
more restriction we will create on the flow going in and out of the chamber.
•Keeping it completely closed will prevent the valve from operating properly while leaving it
completely open will not dampen possible sudden rise in pressure during closure.
Maintenance
CSA automatic control valves XLC 400 series have been designed with a sturdy and reliable
construction to minimize servicing and possible malfunctioning. However we recommend to inspect
them at least twice per year releasing the air accumulated inside the bonnet and checking the
strainer inside the GR.I.F.O, if present, or placed as a separate entity in the circuitry. We
recommend a thorough inspection and maintenance with complete disassembly every 4 years,
according to the following instructions. The solenoid valves ate not a CSA products, they are tested
before supply, user is invited to read and understand the operating principle and make sure to
clean it and maintain the operating parts according to their specific indications (this could change
according to the brands chosen for the job).

XLC 325/425
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MSM – Upstream pressure sustaining/relief pilot
The upstream pressure sustaining/relief pilot
is a diaphragm operated valve, spring
loaded and direct acting, that can be
installed basically in any position.
The function is nothing but to sustain or
relief the upstream pressure regardless of
flow rate and pressure variations.
Operation
The valve is normally opened thanks to the
force exerted by the spring over the
diaphragm, that is opposed to the upstream
pressure applied directly below it.
When the upstream pressure exceeds the
force of the spring the obturator is pushed up
closing the passage through the pilot and
therefore leading the pressure towards the
main chamber and allowing for the valve to
throttle, which will result in a pressure
increase because of the head loss created
between the valves inlet and outlet.
We obtain the regulation by acting on the
screw (21), i.e. clockwise to increase the
pressure and counter-clockwise to decrease
it.
Disassembly
It is not necessary to remove the pilot from
the circuit for the disassembly. Instead use
the enclosed picture which indicates the
numbers specified here below to perform the
operations.
1- Remove the hood of the pilot (4) loosen
the tightening nut (36) and turn the lead
screw (21) anticlockwise, until the spring is
completely unloaded.
2- Remove the screws (33) holding the cover
(20).
3- Separate the cover, the spring (35) and
the spring guide (7).
22
28
39
27
11
40
33
36
10
26
25
29
04 21
12
35
20
07
16
31
30
41
17

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4- Separate the intermediate body (29) from the lower body (22) paying attention not to damage
the O-ring (30)
5- Check the surface of the seat (31) making sure it hasn’t been damaged or scratched
6- Holding the gasket container (39), using an aluminum vise or with buffers in order not to damage
or scratch the material, with a monkey wrench 13 unscrew the tightening nut (12) to remove the
upper flat (10) and the diaphragm (11).
7- With a monkey wrench 24 remove the lower tap (16) and clean it checking for possible dirt or
debris, pay attention not to damage the O-ring (17)
8- Check the plane gasket (28) and, if damaged, contact CSA for further assistance.
Inspection and repair
During these operations carefully check every detail to find damage, in particular the diaphragm
and the sealing seat gasket. The pilot is very sturdy and the materials are designed to
guarantee many years of working conditions for which, generally, it is sufficient to
remove the deposits and make sure to keep the metallic internal components properly
lubricated. If that is not enough we strongly recommend you to contact CSA technical support or
order the maintenance kit.
Reassembly
To reassembly the pilot you have to repeat, obviously in reverse sequence, the same steps
specified in the dismantling phase, while paying attention to:
- Not to exert excessive torque on the locking nuts and upper flats so as not to wear the internal
components, please contact CSA for any doubt related to the torque required to perform the
operation.
- Insert the O-rings back to their position properly lubricated
- Set the screws tight using a criss-cross pattern

XLC 425
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GR.I.F.O. 3 – 3/8″ PN 25
The “GR.I.F.O.” (Integrated Group Filter Orifices) is a CSA unit flow control device that
includes all the necessary functions, needed for the proper regulation and stability of the main
valve. Its compact design makes the entire circuitry easy to be maintained, simple and intuitive yet
allowing a tremendous range of regulations compared to other solutions on the market.
It is completely manufactured in stainless steel AISI 303 and contains:
- a fine mesh filter in AISI 304 (8) to protect the pilot circuit from possible dirt, maintained simply by
unscrewing the tap (9).
- the intervention also called reaction speed regulator* (4) of the main valve, and the opening (3)
and closing (2) speed regulators* of the valve’s main chamber, independent one from the other,
obtained by CSA fine adjustment needle valves.
TEL.[phone]
SALSOMAGGIORE TERME(PR)
GR.I.F.O.-3 G3/8 PN25
VELOCITA' CHIUSURA VELOCITA' APERTURA
CLOSING SPEED OPENING SPEED
ORIFIZIO CALIBRATO
ADJUSTABLE ORIFICE
www.csasrl.it
14 2
4
3
7
13
6
8
9
10
19
1
11 12
5
16
18
17
15

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-replaceable check valves placed upstream of every regulator to limit the flow and control
the acceleration during the valve opening and closing.
- an upstream outlet not filtered protected by a cap 1/8 G
- an upstream pressure outlet filtered, 1/8 G, protected by an air valve.
- The adjustment is normally done in the factory although it is possible to modify it on the spot, in
order to find the optimal regulation according to the function required.
Herewith enclosed are the optimal values for the most common XLC applications expressed in
terms of revolutions, starting from the fully closed position and turning anticlockwise.
The regulators are needle valves designed by and exclusive property of CSA Srl and the
rotation permits to obtain a specific passage. For example the regulation 3 means that, starting
from the complete closed needle (turned clockwise), unscrewing 3 turns in opening you will get
the indicated regulation.
Maintenance
The “GRIFO” is particularly sturdy, extremely simple and reliable so it does not require
maintenance but we strongly advise to proceed regularly, at least twice per year, with a clearing of
the filter from dirt and deposits, simply by unscrewing the tap (9) and washing the mesh. This
procedure can be carried out without interrupting the flow through the main valve, and simply by
isolating the main circuit by means of the isolation ball valve and removing the pressure right
upstream of the GRIFO.
Type
Reaction
speed
Opening
speed
Closing
speed
XLC 410
3
1
5
XLC 412
3,5
4
4
XLC 420
3
3
4
XLC 430
3
1
5
Others
Please contact CSA for informations.

XLC 425
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Needle valve 3/8" - VS
VS needle valve is exclusive property of CSA srl and its mainly used whenever GRIFO is not
necessary, like XLC 440, XLC 450, XLC 460, and more in general where we need to decrease the
flow control of the main chamber to very limited values.
VS is completely made in S.S. therefore extremely sturdy and impervious to era and cavitation
phenomena, nevertheless we recommend carrying out maintenance to remove scale deposits.
Servicing is very easy and straightforward and if you have any problems doing that please contact
CSA tech support immediately or refer to the above picture to order spare parts.
1
2
4
5
3
3 Needle
5 O-Ring
Spare parts kit
4 M6 nut
2 Sleeve
1 Body Stainless steel
Stainless steel
Stainless steel
NBR
Stainless steel
N. COMPONENT MATERIAL
1
1
1
N.
1
1
3-5

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A2 Two ways flow accelerator
The two ways flow accelerator A2 is a
diaphragm operated valve, with the purpose
of opening and closing in response to
pressure variations applied to the upper
chamber. It is used to enhance the flow
capacity in combination with other
components of the valve’s circuitry to reach
the required response time and functions.
Operation
The valve is composed of an upper chamber,
diaphragm inside linked to the mobile block
composed of obturator, upper flat, opening
and closing the passage through the seat to
generate or interrupt flow through the circuit.
This is due to the difference in surface
between the upper disk (5) receiving the
pressure of the main chamber and the
sealing seat onto which the obturator (7) is
acting. Should the pressure applied on the
inlet and on the chamber be the same the
valve will close, thanks to the difference in
force. Should the chamber be put in
communication with the atmosphere the valve
will be pushed to the open position thanks to
the pressure exterted below the obturator.
Disassembly and maintenance
The flow accelerator A2 has been designed
to tolerate many cycles without any
maintenance. We recommend to carry out the
following steps every 4 years.
-Drain out all the pressure before proceeding
-Remove the screws (10)
-Take out the cover (2)
-Pull out the spring (3)
-Take out the mobile block including obturator
block and diaphragm (6)
-Unscrew the nut (4)
-Pull out the disk (5) and the diaphragm
-Inspect the diaphragm looking for damages,
scratches and replace if needed
-Inspect the plane gasket (9), replace if
necessary
-Inspect the seat obtained on the body (1) by
machining looking for possible sign of
corrosion and damages.
N. Component Material
1
2
3
4
5
6
7
8
9
Body
Cover
Spring
Nut
Disk
Obturator
Diaphragm
Plane gasket
Stainless steel
Stainless steel
Stainless steel
Stainless steel
Stainless steel
Stainless steel
Neoprene
NBR
10 Screw Stainless steel
11 Tap 1/8G
Screws Stainless steel
Stainless steel
7
1
2
5
3
8
9
4
6
10
11

XLC 425
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Visual position indicator
The visual position indicator, normally present on CSA
valves unless otherwise stated, is extremely useful to
detect the movement of the shaft therefore of the internal
mobile block during working conditions. This is to assess
the absence of vibrations, chattering and to confirm the
proper behavior of the valve. Entirely made in stainless
steel a transparent glass pipe will show the movement of
the position indicator sliding inside while an air release on
top, operated by a pin (4), will enable customer purge out
air pockets accumulated during working conditions inside
the control chamber of the main valve.
Disassembly
The CSA position indicator is a sturdy and solid item not
subject to maintenance, in case of frost and unexpected and
accidental impact it may break. For the disassembly simply
hold the lower part (2) and unscrew the upper part (1). Make
sure the plane gaskets (5-6) are not damaged or lost during
this phase, clean and replace if necessary. The glass pipe
(3) can be cleaned in case of dirt accumulated inside and
turbidity. The upper pin (4) is inserted and equipped with an
O-ring, do not remove it unless strictly required.
N. Component Material
1
2
3
4
Upper part
Lower part
Glass pipe
Pin
stainless steel
stainless steel
Pyrex glass
stainless steel
3
4Gasket Gasket Vulkolan Vulkolan
4
5
3
1
6
2

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Interventions on the main XLC valve
In case of malfunctioning or defects,that can be found on the main valve, is possible to intervene
without removing the product from the pipeline. The defects can be either internal and external.
The external defects mainly concerns the pilot circuit and are not related to the main body of the
XLC 400 control valve.
The internal defects concern the mobile block, or the deterioration of the internal components.
Problems can be summed up in three categories:
a) the valve is blocked, the mobile block does not move;
b) the mobile block moves but the valve does not react because thediaphragm is damaged.
c) the diaphragm is OK but the valve does not close or leakages is reported.
The possible causes lead
to:
•defects on the
diaphragm;
•defects on the movements of the mobile
block;
•friction caused by
deposits and corrosion;
•problems on the
gaskets;
•defects on the sealing
seat.
15
13
21
14
17 16 118 4
10 5
9
3
7
2
8
11
12
20
19
6
N. Component Material
1
2
3
4
5
6
7
8
9
Body
Cap
Position indicator
Pressure outlet tap
Upper flat o-ring
Obturator o-ring
Indicator stem
Main shaft
Guide ring
GJS 450-10 or GJS 500-7
10 Spring
11 Locking nut
12 Upper flat
13 Diaphragm
14 Obturator
15
16
17
18
19
20
21
Plane gasket
Gasket holder
Seat
Seat o-ring
Studs
Nuts
Washers
St. steel/Ni-plated brass
AISI 302
AISI 303/AISI 304/AISI 316
AISI 304/AISI 316
AISI 304/AISI 316
GJS 450-10 or GJS 500-7
AISI 316
NBR/EPDM/Viton
NBR/EPDM/Viton
AISI 303
AISI 303/AISI 316
Bronze/AISI 303/AISI 316
AISI 303/AISI 316
Painted st./AISI 304/316
Neoprene-nylon
St. st./paint. st./GJS 450-10/500-7
NBR
AISI 303/AISI 316
NBR/EPDM/Viton
AISI 304/AISI 316

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Problems solving
Problem
Cause
Solution
The main valve doesn’t
close
The gate valves are closed
Open the gate valves
The ball valves of the circuit are
closed
Open the ball valves
There is no pressure inside
the main chamber
Check the pressure coming
into the circuit
The diaphragm is damaged ( see
the following section “checking the
diaphragm”)
Replace the diaphragm
The mobile block is stuck due to
corrosion, deposits, cavitation
Clean the main shaft
and replace all the
components affected by
deposit or corrosion
The mobile block is stuck due to
stones, pebbles, trapped inside the
main body
Remove the material from
the valve
The plane gasket of the obturator of
the main valve and/or of the pilot is
ruined
Replace the plane gaskets
The sealing seat is ruined
Replace the sealing seat
The main valve
doesn’t open
The gate valves are closed
Open the gate valves
The ball valves of the circuit are
closed
Open the ball valves
There is no pressure on the main
supply line
Check the upstream
pressure
The pilot set point is higher than the
incoming pressure value
Reduce the upstream
pressure set point by turning
the screw anticlockwise to
generate the opening
The mobile block is stuck due to
stones, pebbles, debris that remain
trapped inside the valve
Clean the main shaft
and replace all the
components affected by
deposit or
corrosion

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1) Checking the diaphragm
In order to verify if the diaphragm has suffered any damage simply proceed as follows:
a) slowly close the upstream and downstream gate valves;
b) close all the ball valves of the circuit;
c) completely open the air vent valve from the position indicator, if the latter is not present
the fitting of the isolation valve on the chamber;
d) open the upstream gate valve slowly but not completely little by little so that the pressure enters
the main valve body.
The water that flows will raise the mobile block and the membrane therefore, the air vent will
discharge the remaining water trapped inside the main valve bonnet.
When all the water of the main chamber has been expelled (this operation could take a few
minutes and is related to the DN of the valve as well as the opening percentage of the upstream
gate valve) if the membrane is not damaged, the flow will come to an end and you can be sure the
cause of the problem has to be found somewhere else.
On the contrary if the flow keeps going the diaphragm is surely damaged or the nut fixing the
membrane to the shaft is not tightened enough, therefore intervene accordingly, simply by
replacing the diaphragm or setting the nut tight.
Warning: remember to close the upstream gate and decrease all the remaining pressure inside
the valve before removing the bonnet.
Movement of the mobile block
In order to verify the proper movement of the mobile block to proceed as follows: isolate the main
chamber closing the two isolation ball valves on the upstream and downstream side of the valve’s
body, and open the drain port located on top of the position indicator. In this way you will relief the
pressure out of the valve’s bonnet.
Attention: with this operation we will basically open the valve completely, therefore no regulation
will be performed. Make sure to avoid dangerous consequences of the pressure system onto which
the valve is acting.
When the main valve is completely opened mark the glass of the indicator to the
corresponding position.
Now close leave the isolation ball valve downstream and open the correspondent upstream, also
close the air release valve on the position indicator. The main valve will close.
Verify that the valve closes following the movement downwards of the indication rod (a slowing
down in the final phase is normal and caused by the bending and adjustment of the diaphragm).
When the valve is closed, mark the glass of the indicator to the corresponding position and verify
that the movement of the rod is like the one indicated below, if different, then means that there is
something preventing the proper movement of the mobile group and please contact CSA
immediately.
DN in mm
50
65
80
100
125
150
200
250
300/400
Stroke in mm
15
18
21
27
27
43
56
70
84

XLC 425
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19
The clogging can be located between the seat and obturator if the indication rod is in closed
position and the flow continues, or between the sealing seat and cap if the valve does not reach
the complete opening. Before proceeding to dismantling the cover, it is suggested to do some
manual opening and closing operations putting the main chamber under pressure and discharging
it. This operation proved to be enough in some situations to flush the dirt downstream. If not take
the cover apart.
3) Friction of the shaft
One of the more frequent causes of the mobile group movement obstruction are the
corrosion and deposits on the main shaft causing friction. They can be due to particles (conveyed
from the water) or to limestone deposits (for extremely hard water) that in the long run cause the
jamming of the main shaft on the guiding devices, because of the high friction value.
Should that be the case simply proceed to a proper cleaning leaving it in a muriatic acid solution
5% as long as necessary, shouldn’t that be sufficient then proceed with a fine abrasive cloth until
the deposit is completely removed.
4) Plane gasket
The valve must close watertight once the pressure has entered the main chamber and if we have
enough pressure to do it which is at least 0,5 bar acting on the pilot in addition to headloss during
outflow, if that doesn’t happen proceed with the inspection of the plane gasket performance
assuring the closure between the obturator and the sealing seat.
5) Sealing seat
One more reason that could be responsible for the improper closure of the valve may be the
sealing seat, occurring in case of dirt and deposits or damaged due to cavitation. In these cases
we must proceed with an accurate inspection to clean the component by means of sandpaper
then polish it, if the problem can’t be solved on the spot please contact CSA technical support for
immediate assistance.

XLC 425
For further information please consult us at: www.comeval.es
20
Disassembly
As mentioned before make sure that the gate valves upstream and downstream of the valves have
been properly closed and set tight.
Relieve the pressure of the main chamber simply by closing the isolation valves of the circuit and
opening one of its fittings. Proceed with the removal of the circuitry, in order to facilitate the
intervention on the cover, only after having noted down the layout
Remove the nuts (4) and the washers (5). If the valve has been working for a long time you may
notice that all the parts in contact with the diaphragm will tend to get stuck, in this case simply hit
the lower part of the cover to loosen it by means of a plastic hammer and a chisel driving it
upwards. After that, hoisting the valve vertically using eyebolts. Remove the internal mobile block
and put it into a grip with clamps in soft material such as brass or aluminum, be extremely
careful doing that because the upper and lower main shaft surface responsible of the valve-s
guiding mechanism , if worn or etched, may cause the blocking of the valve due to its bind in the
bearings.
Remove the nut and the washer (10) take off the upper flat (11) the O-rings (21) check the
diaphragm looking for damage and, after having pulled out the plane gasket (13)by means of a
screw driver ( please make sure not to wear the gasket itself or its housing) examine it carefully.
Check the driving bush on the cover (7).
Examine the sealing seat (15) looking for scratches that may affect the proper water tightness and
for possible sign of cavitation.
The sealing seat is made in stainless steel and it usually doesn’t require particular
maintenance, a very important thing though is to guarantee proper cleaning by means of sand
paper.
Up to DN 150 the sealing seat is screwed into the body while for the remaining DN it is set tight by
several screws. To carry out a further inspection and removal of the sealing seat, and in case of
cavitation, please contact CSA technical support for immediate assistance.
Inspection
After all the components have been dismantled we need to look for any damage caused by wear of
the surface, deposits, corrosion or something else.
It is strongly advised to replace every 4 years all the components made in rubber, responsible for
the water tightness of the valve, such as O-Rings, the diaphragm, the plane gasket.