Seawater Service Pressure Relief Valve
INTRODUCTION
The Cla-Val 50-20/650-20 is an automatic control valve designed
to maintain constant upstream pressure to close limits. It is a
hydraulically operated, pilot controlled, modulating type valve.
The valve is actuated by inlet line pressure, opening to maintain
a steady line pressure and closing gradually to prevent surges.
When inlet pressure is below the pressure setting CRL pilot control,
the main valve and pilot are closed drip tight. Pressure setting
adjustment is made with single adjusting screw that has a protective
cap to discourage tampering.
INSTALLATION
1. Allow sufficient room around the valve assembly to make
adjustments and for servicing.
2. lt is recommended that gate or block valves be installed to
facilitate isolating valve for preventative maintenance. When used
as a surge control or pressure relief valve where valve outlet dis-
charge is to atmosphere, then a gate or block valve is needed at
valve inlet.
NOTE: BEFORE THE VALVE IS INSTALLED, PIPE LINES
SHOULD BE FLUSHED OF ALL FOREIGN MATTER.
3. Place valve in line with flow through valve in direction indicated
on inlet plate or flow arrows. Check all fittings and hardware for
proper makeup and verify that no apparent damage is evident.
4. Cla-Val Valves operate with maximum efficiency when mounted
in horizontal piping with the cover UP; however, other positions
are acceptable. Due to size and weight of cover and internal com-
ponents on six inch and larger valves, installation with the cover
up is advisable. This makes periodic inspection of internal parts
readily accessible.
5.
Caution must be taken in the installation of this valve to insure that
galvanic and/or electrolytic action does not take place. The proper
use of dielectric fittings and gaskets are required in all systems using
dissimilar metals.
OPERATION AND START-UP
1. Prior to pressurizing the valve assembly make sure the nec-
essary gauges to measure pressure in the system, are installed
as required by the system engineer. CAUTION: During start-up
and test a large volume of water may be discharged down-
stream. Check that the downstream venting is adequate to pre-
vent damage to personnel and equipment. All pilot adjustments
should be made slowly in small increments. If the main valve
closes too rapidly it may cause surging in upstream piping.
2. If isolation valves (B) are installed in pilot system open these
valves (see schematic).
3. Remove cap on the CRL Pressure Relief Control, loosen jam
nut and turn adjusting screw clockwise until spring is fully com-
pressed. This puts the control in full closed mode and will cause
the main valve to close when system is pressurized.
4. If a downstream block valve is installed, slowly open this valve.
5. Partially open upstream block valve. The main valve should
close.
6. Carefully loosen the plug at top of indicator assembly.
Bleed air from cover and tighten plug or bleed valve.Carefully
loosen tubing fittings at highest points and bleed air from system.
Retighten fittings.
7. Open fully the upstream block valve and turn the CRL adjust-
ing screw slowly counterclockwise until you begin to hear a flow
through the control. The main valve should start to open. If the
pressure is below the required relief setting, refer to the spring
chart and turn the adjusting screw clockwise the number of turns
required for the proper setting. Lock the jam nut and replace
cover. An observation of the pressure relief setting should be made
during usage. The controls can be readjusted as required.
MAINTENANCE
1. Cla-Val Valves and Controls require no lubrication or packing
and a minimum of maintenance. However, a periodic inspection
schedule should be established to determine how the fluid is
affecting the efficiency of the valve assembly. Minimum of once
per year.
2. Repair and maintenance procedures of the Hytrol Main Valve
and control components are included in a more detailed IOM
manual. It can be downloaded from our web site (www.cla-val.com)
or obtained by contacting a Cla-Val Regional Sales Office.
3. When ordering parts always refer to the catalog number
and stock number on the valve nameplate.
INSTALLATION / OPERATION / MAINTENANCE
50-20/650-20
MODEL
SYMPTOM PROBABLE CAUSE
REMEDY
Main valve Inlet pressure below setting of
Reset pilot valve. If change
won’t open pilot valve
in setting is from tampering,
seal cap with wire and
lead seal
Pilot valve stuck closed Mineral
Disassemble control and clean
deposit or foreign material between
disc retainer and power unit body
Pilot valve diaphragm ruptured or Disassemble and replace
diaphragm nut loose. Water coming diaphragm Tighten nut
out of the vent hole in cover
Main valve stuck closed
Disassemble main valve,
clean
Mineral buildup on stem
parts and/or replace damaged
Stem damaged
part. Check downstream
and
cover CK2 isolation
valves are open
Main valve Inlet pressure above setting of
Reset pilot valve
won’t close pilot valve
Clogged needle valve or strainer
Disassemble and clean
Pilot valve stuck open. Mineral
Disassemble and clean
deposit or foreign material under
disc retainer or under diaphragm
assembly
Main valve stuck open. Mineral
Disassemble and clean
buildup on stem. Foreign material
between seat and disc assembly
Main valve diaphragm worn
Disassemble and replace
Valve leaks Pilot valve disc worn out
Disassemble and replace
Continuously Main valve disc worn or small
Disassemble and replace
pin hole in main valve diaphragm
Set point too close to inlet pressure Reset CRL Pilot
