CSA XLC 400 Series User manual

XLC 470
1
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CSA waterworks line
Altitude automatic control valve
Mod. XLC 470

XLC 470
2
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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 400 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 400 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 are listed on the assembly drawing depicted on the pictures of the
manual (ref assembly drawing) These parts should be stocked to minimize delays in case of
malfunction. When ordering spare parts please make reference to the assembly drawing and
indentification plate present on the valve.

XLC 470
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Contents
Description - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 4
Handling and storage - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 5
Installation - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 6
Set up - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - - - - - - - -7
Maintenance of MPZ Pilot- - - - - - - - - - - - -- - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - 10
Maintenance of GRIFO- - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 12
Visual position indicator- - - - - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -14
Maintenance of general XLC 400 valve body- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 15
Troubleshooting- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -- - --- - - - - - - - - -16

XLC 470
4
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Description (ref. picture 1 on page 4)
The pilot operated control valve XLC 400 series Mod. 470 is designed to automatically maintain a
constant level of a tank, regardless of upstream pressure variations, through a high sensitivity pilot
connected to the static pressure (5) of the tank itself. The response of the valve is proportional to
the level variation within 40 cm accuracy.
Picture 1
XLC 470
N. Component Material
1
2
3
4
5
6
7
8
9
Main valve XLC
Isolation valve
Isolation valve
Isolation valve
Grifo 3/8"
MPZ altitude pilot
Position indicator
Pipes
Fittings
GJS 450-10 or 500-7
AISI 316
AISI 316
AISI 316
AISI 303
Bronze/AISI 303
AISI 303
AISI 303/316
AISI 316
Isolation valve AISI 316
10
8a Position indicator for DN300-400 Brass/AISI 303
5
9
10
2
1
4
6
7
3
8
8a

XLC 470
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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 470
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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.
Installation
The automatic control valve XLC 400 must be always installed in a horizontal position with the
bonnet upwards. Smaller valves, (150 mm and smaller) can be installed in a vertical pipe shouldn’t
be unavoidable. Prior to that consult us 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 upstream . This to avoid the accumulation of air pockets during
working conditions and allow air discharge during pipe filling and commissioning.
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 or pilot
operated modulating devices.
If not included in the order install pressure gauges upstream and downstream, 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.
Make sure to have at least 0,35 bar of static pressure (rif. Nr 5 of picture 1 on page 4)
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.
During handling be sure not to damage the glass of the position indicator, if present.
Note to the engineer:

XLC 470
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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.
The connection to the pilot’s pressure port should always sense the static pressure of the tank, do
not use the inlet out outlet pipe from the tank

XLC 470
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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.
Set up
For the proper set up of XLC 400 Mod. 470 reader is advised to use the following points (rif. picture
1 on page 4).
Make sure the isolation ball valves of the circuitry (2-3-4-5) are fully open
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 in the order remove the hood from the pilot (7)
and turn anticlock wise the screw to decrease the spring force in the cover almost
completely. The static level of the tank depends on the pilot setting and it is proportional to
the charge of the spring. Regulation charts are available on request.
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 to the closing position still
ensuring some flow towards the tank.
Should the total closure be needed user is invited to close the ball sectioning valve (3)
Remove the air entrapped in the bonnet, during the operation, by means of the air release
device located on top of the position indicator (8) leaving it flowing for at least 20 seconds.
Open completely the upstream gate valve
Open the ball valve (3) if it has been closed
Slowly open the downstream gate valve, to a maximum of 40% of the stroke, to generate
some flow through the valve and give the valve enough time to react, this depends on how
big is the system downstream and on the variations in demands.
Having decompressed, the spring as per indications mentioned above unless a specific
setting was required in the order, the XLC 470 control valve will tend to maintain the level of
a tank to a very low level therefore interrupting the supply (if lower than the current value
sensed on the pressure port 5)
Slowly act on the regulation screw on the pilot (7) turning it clockwise, thus increasing the
required level of the tank
The valve will open accordingly generating some flow
Open completely the downstream gate valve

XLC 470
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Valves epoxy painted using FBT requires washers flat washers to be installed on the
flanges connections to prevent the paint from cracking or chipping.
Once the valve has reached the desired value set the locking nut and place the hood on top
of the pilot. Check manually acting on the pilot for the proper response of the valve within +-
30 cm
Make sure the pilot’s sensing port 5 is always in communication with the static pressure of
the tank and no air pockets or excessive bends and /or headloss (on the piping between
the static value and the pilot) are affecting such value
The unit flow control device GR.I.F.O. is exclusive from us 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 our technical support.
Valves epoxy painted FBT
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.

XLC 470
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MPZ –Altitude control pilot
The altitude control pilot is a diaphragm
operated valve, spring loaded and direct
acting, that can be installed basically in any
position. The function is to reduce and
stabilize the downstream pressure value
taken on the sensing port, regardless of flow
rate and upstream pressure fluctuations,
usually being the static pressure of the tank
to the maintained (installation details on
page 7).
Operation
The valve is normally opened thanks to the
force exerted by the spring over the
diaphragm, that is opposed to the static
pressure applied directly below it through the
sensing port (30) Should the latter exceed
the force of the spring the obturator (19) is
pushed up closing the passage through the
pilot (19), therefore leading the pressure
towards the main valve chamber to throttle
the flow, until the level inside the tank
(producing the static value sensed on the
pilot) had dropped due to the consumptions.
We obtain the regulation by acting on the
screw (04), after having removed the hood
(3) i.e. clockwise to increase the tank level
and counter-clockwise to decrease it
(regulation charts available on request
depending on the spring used for the
application).
Disassembly
It is not necessary to remove the pilot from
the circuit for the disassembly. Instead use
picture on the left, with the corresponding
components and materials, which indicates
the numbers specified here below to perform
the operations.
1- Remove the hood of the pilot (3) loosen
the tightening nut (5) and turn the lead
screw (4) anticlockwise, until the spring (7) is
completely unloaded
2- Remove the screws (14) separating the
upper part (15) from the lower part (16) (
6
11
26
924
3
7
5
14
30
20
22
19
17
10
25
2
4
16
23
21
1
29
15
13
12
8
18
28
27
N. Component Material
1
2
3
4
5
6
7
8
9
Body
Cover
Hood
Driving screw
Nut
Spring guide
Spring
Self-locking nut
Upper flat
Ni-plated bronze/st. steel
10 Diaphragm
Obturator holder
Sealing seat
Gasket holder
Plane gasket
18
19
20
21 Tap
O-ring
Screws
O-rings
Stainless steel
Neoprene
NBR
Stainless steel
NBR
Ni-plated bronze/st. steel
Stainless steel
Stainless steel
Stainless steel
Painted steel/st. steel
Stainless steel
Stainless steel
Stainless steel
Stainless steel
Stainless steel
NBR
Stainless steel
Stainless steel
Stainless steel
22
11 Diaphragm lower disk
12 O-ring
13 Shaft
14 O-ring
15
16
17
Upper flange
Lower flange
O-ring Ni-plated brass/st. steel
Stainless steel
NBR
Stainless steel
NBR
Ni-plated brass/st. steel
NBR
23
24
25
26
27
Screws
Screws
Spare parts: 12-14-17-21-23-27
Pressure port
28
29
30
Inlet
Outlet

MRV
11
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3- Take out the upper part with the cover (2), the spring (7) , the spring guide (6). Do not separate
the cover (2) from the upper part (15) unless strictly required, to do so loose and unscrew the
screws (24)
4- With a monkey wrench remove the self clocking nut (8) and pull out the upper flat (9)
5- Remove the diaphragm (10) inspect the surface, clean it and replace if necessary or in case of
scratches, damages
6- Loosen and remove the screws (26) holding the body (1) to the lower part (16)
7- Remove the diaphragm lower disk (11) from the shaft (13), paying attention not to damage the
o-ring (12)
8- Pull up the lower part (16) and unscrew the shaft (143) from the obturator holder (18) paying
attention not to scratch its surface (use aluminum clamps or materials suitable for it on the grip),
failing in doing so would generate too much friction for the pilot to operate properly
9- Remove the tap (22) paying attention not to damage the o-ring (23)
10- Remove the obturator (20) from the obturator holder (18)
11- Inspect the plane gasket (21)
12- Inspect the seat (19) making sure no sign of damages, scratches or corrosion are present, if
necessary remove it using a 13 tube key
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 our 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 disassembly phase, while paying attention to:
- use Loctite 50 ( thread lock suitable for disassembly so not too strong) for all the threaded parts
without o-ring
- Inspect clean and repair if necessary every component , in particular those exposed to the
contact with water and responsible of the water tightness

XLC 410
12
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GR.I.F.O. 3 –3/8″ PN 25
The “GR.I.F.O.” (Integrated Group Filter Orifices) is a 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).
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

XLC 470
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- 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 us fine adjustment needle valves.
-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.
Reaction
speed
Opening
speed
Closing
speed
XLC 410
3
1
5
XLC 410 ND
3
2
5
XLC 410 T
3
1
5
XLC 412
3,5
3
4
XLC 415
3
1
5
XLC 420
3
2
4
XLC 424
3
2
4
XLC 425
3
2
4
XLC 430
3
3
3
XLC 431
3
3
5
XLC 434
3
3
3
XLC 435
3
3
3
XLC 470
3
3
3
The regulators are needle valves designed by us 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.

XLC 470
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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
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

XLC 470
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Interventions on the main XLC 400 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 the diaphragm 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

XLC 470
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Problems solving
Problem
Cause
Solution
The main valve doesn’t
close
The sealing seat is ruined
Replace the sealing seat
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 is
ruined
Replace the plane gasket
The static pressure sensed by the pilot
is below the valve’s set point
Adjust the pilot’s set point level by
reducing the force on the
spring(turning anti clock wise)
The main valve
doesn’t open
There is no pressure on the main
supply line
Check the upstream pressure
The ball valves of the circuit are
closed
Open the ball valves
The static pressure sensed by the pilot
is above the pilot’s set point
Adjust the pilot’s set point level by
reducing the force on the
spring(turning clock wise)
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

XLC 470
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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 us
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 470
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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 our technical support for
immediate assistance.

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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 our 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.

XLC 470
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Reassembly
To reassemble do the reverse of the disassembly procedure positioning the main shaft back into
the grip along with all the pieces. It is very important not to forget the O-Ring (21) and to set the
nut tight (10) to assure a proper torque between the diaphragm and the plane gasket. Please be
extremely careful with this step because a nut not properly tight may engender movements making
the mobile block unstable, therefore affecting the valve’s performance.
Put the mobile group back into the valve’s body placing the shaft into the sealing seat guide, make
the holes of the diaphragm match the studs and position the spring (9) under the cover.
Set the nuts tight using a cross over pattern, then put the circuitry back to its original position.
Final inspection
Make sure that the internal mobile block can move without any friction, this can be verified simply
by gradually putting the main chamber under pressure and checking the movement of the
indication rod, as explained before.
Examine the status of the plane gasket simply by checking the perfect water tightness of the
sealing seat. At this point proceed by opening the upstream gate valve full throttle to have the
normal working conditions, check for any leakage through the cover or the nuts, should that
happen set them tighter.