6
K129e
JAN 2014
SERVICE AND MAINTENANCE
These tamper-resistant car tridge pressure-relief
valves are accurately factory set and do not require
any field adjustments whatsoever. They are intended
for one time over-pressure operation and should be
replaced immediately after discharging because
setting or seat tightness may be altered. Annually,
EZ-SRV™ cartridge pressure-relief valves shall be
visually inspected for corrosion or accumulation of
scale and for leaks. Removal of the cartridge is not
normally required for inspection. Pressure-relief valves
should be removed and replaced with new valves at
least every five years. Even when simply replacing an
existing valve, a review of requirements per current
local and national code is advisable. Valves must
not be removed unless system has been evacuated
to zero pressure.
CARTRIDGE REPLACEMENT
Hansen EZ-SRV™ cartridge pressure-relief valves can
be replaced safely and easily. First close the three-way
manifold valve to the pressure-relief valve. Slowly bleed
the pressure between the three-way manifold valve
and the pressure-relief valve to zero pressure. Turn
the EZ-SRV™ cartridge two turns to relieve pressure
to the discharge piping. Be sure there is no residual
pressure and slowly remove the EZ-SRV™ cartridge
valve. Clean the interior of the EZ-Fitting especially
where the two o-ring surfaces are located. Make sure
the EZ-SRV™ cartridge valve setting and capacity
(see Nameplate section) match the one being replaced
and the requirements of the system design. Lightly oil
or grease the o-rings on the replacement EZ-SRV™
cartridge valve and screw into the EZ-Fitting. Tighten
to approximately 75 foot-lbs (102 Nm). Wire lugs are
provided for optional tamper evident sealing using
customer provided locking wire and seal. Next, with a
pressure gauge installed on the gauge valve, open the
three-way manifold slightly to reach normal pressure.
Check for leaks at the EZ-Fitting and EZ-SRV™ cartridge
valve joint. Open the three-way valve completely to put
the pressure-relief valve back in service.
Punch out the year and month on the installation date
tag. The five year replacement date will show on the back.
LIQUID RELIEF VALVES
Hansen Technologies offers EZLQ pressure-relief valves
for liquid relief applications. Typical applications include
ASME vessels, oil coolers and other components that can
be isolated by control valves or manual shut-off valves.
Hansen EZLQ liquid relief valves operate on pressure
differential. Set points are low differentials of 50, 75, and
100 psid. The equipment the liquid relief valve is protecting
must be designed for a pressure greater than the sum of
the design operating pressure of the outlet piping plus
the differential pressure of the liquid relief valve.
Sizing the capacity of the liquid relief valve depends on
the liquid properties and the rate (U.S. GPM) of heating of
the liquid. Details on calculating the flow rate are given in
the ANSI/IIAR 2-2008 Appendix G and API Standard 520.
Installation and servicing of liquid relief valves may require
special precautions. Liquid relief valves should be piped
back into the system, not to atmosphere. Appendix M of
Section VIII, Boiler & Pressure Vessel Code has general
information on installation and service of liquid relief valves.
GAUGE VALVES AND PRESSURE GAUGES
Hansen EZ-Fittings have a 1/4˝ inlet pressure port and
come with a factory installed hex head plug. It is strongly
suggested that the port be fitted with an MPTxFPT gauge
valve, such as the Hansen H7771, to facilitate safer and
controlled servicing. The hex head plug should be installed
in the gauge valve outlet to prevent accidental refrigerant
loss. Alternately, the gauge valve can be fitted with a Hansen
HG27 pressure gauge. This compact pressure gauge
features a 2˝ (50 mm) diameter face with an easy-to-read
dial. The black needle indicates current sensed pressure,
and is useful when replacing a valve, determining which
relief valve is active, monitoring vessel pressure, or for
general system troubleshooting. The red tell-tale needle
indicates the highest pressure as seen by the gauge. This
can be useful in identifying which relief valve has discharged
or has experienced an abnormally high pressure. The
tell-tale needle can be easily reset for monitoring purposes.
Catalog Number: HG27 Pressure Gauge
Connection: 1/4˝ MPT
Safe Working Pressure: 600 psig (41 bar)
Scale Range: 0 psig to 600 psig and 0 to 4000 kPa
A m b i e n t Te m p e r a tu r e R a n g e: + 32 º F to +125° F
(0°C to +52°C). Contact Hansen for application below
+32°F (0°C) ambient temperature.
Suitable for ammonia and other Hansen approved
refrigerants.
2.00" (50 MM)
RED TELL-TALE
BLACK
ADJUSTMENT
SCREW
1/4" NPT
3.00"
(75 MM)
NEEDLE
NEEDLE
DIA FACE
60
0
50
0
300
20
0
10
0
0
400
0
psi
k a
20 0
1000
3000
4000
kPa
inch
:
No.
:
Serial
Air
Capacity
:
Pressure
:
Size
Set
I n l e t
Cat. No.
:
O u t l e t
HANSEN TECHNOLOGIES
U.S.A.
CORPORATION
1/4" INLET
PRESSURE PORT
WIRE LUGS
O-RINGS
EZ-FITTING
GAUGE
VALVE
H771
OPTIONAL
PRESSURE
GAUGE
HG27
OPTIONAL
INSTALLATION
DATE TAG
RELIEF
VALVE
PRESSURE-
CARTRIDGE
EZ-SRV
60
0
50
0
300
20
0
10
0
0
400
0
psi
k a
20 0
1000
3000
4000