4
K129e
JAN 2014
INSTALLATION
Protect pressure-relief valves from dirt and moisture.
Match capacity on valve nameplate to system document
as specified by system designer and based upon
protected vessel size. Mount valve directly at the vapor
space of pressure vessel or on connecting non-valved
vapor piping as close to the vessel as possible. (Model
EZLQ liquid relief valves can be connected where
liquid is to be expected and relieved to a similar or
lower pressure, not to exceed the set pressure of the
relief valve. Generally, the relief valve is piped around
the isolation valve of the protected section or vessel).
EZ-SRV™ Cartridge pressure-relief valves should be
installed upright.
Never expose your face or body to a connected relief
valve exit or piping.
Check that the valve setting and capacity (see Nameplate
Information Section) meets the requirements per
system design in accordance with local and national
regulations. Isolate the valve and related piping from
the refrigeration system and pump out pressure to zero
before attempting to install or replace any pressure-
relief valve. Use appropriate safety equipment. Avoid
residual refrigerant when doing so. A gauge valve and
gauge can be installed in the inlet pressure port for
future use to verify and control any refrigerant which
might remain. See also Gauge Valves and Pressure
Gauges section on page 6.
Remove shipping caps from the EZ-Fitting. Thread or
weld EZ-Fitting into the pressure vessel or three-way
dual shut-off valve at a location in the vapor space
above the liquid refrigerant level. Install the EZ-SRV™
cartridge pressure-relief valve into the EZ-Fitting and
tighten to approximately 75 foot–lbs (102Nm). These
valves are for gas relief only. (For liquid relief, Hansen
offers the EZLQ relief valve specifically designed for
liquid, refer to page 6). Do not install shut-off valves in
line with pressure-relief valves. Install valves in locations
where they will not be damaged by moving equipment
such as lift trucks, etc. Install valves in a manner that
enables them to be replaced.
When a dual pressure-relief system is being put into
service, the three-way valve stem should be positioned
so that only one valve is exposed to pressure. While
the three-way valve can be either frontseated (front
port is closed) or backseated (back port is closed), the
backseated position is recommended because it takes
pressure off the packing and reduces the possibility of
packing leaks.
Vent the relief valve exit to a safe outdoor location in
an approved manner away from people and building
openings. Do not install valves or vent piping in a
refrigerated space unless precautions are taken to
prevent moisture migration into the valve body or the
relief vent line. Avoid trapped ice build-up between
valves and other equipment.
Only apply thread sealing compound to external pipe
threads and use a modest amount to avoid getting
compound inside the valve. Use brackets or hangers
to support the pipe and prevent the valve from being
overly stressed. Do not put undue stress on the valve
by using it to stretch or align pipe.
Pressure test all valves and related piping for leaks.
When testing a dual pressure-relief system, the three-
way valve stem should be in the mid position (only during
testing), ensuring that all valves are properly leak tested.
Do not discharge valves prior to installation or when
pressure testing. Never attempt to reset or change the
valve setting. Always replace cartridge pressure-relief
valves once they have discharged.
Hansen EZ-SRV™ valves come with an installation date
tag to identify the number of years the valve has been
in service. When installing the EZ-SRV™ valve, remove
the knockouts corresponding to the current year and
month. Use a pen to push the knockout partially through
the tag and tear away from other side.
Pressure-relief valves for ammonia refrigeration are
subject to preventative inspection and maintenance or
periodic replacement. Normal replacement is five years
from installation. However, once a valve discharges it
must be replaced as soon as possible. Self-reseating is
not dependable because of the possibility of dirt lodging
on the seat surface allowing the valve to leak or “weep”.
REPLACING EXISTING RELIEF VALVES
EZ-SRV™ cartridge pressure-relief valves have the
same capacity as the Hansen H5600 “R” series relief
valves. The Hansen EZ-Adapter is available to make
the inlet and outlet connection dimensions the same
as the Hansen H5600 series. This minimizes piping
changes to the discharge line connections. The EZ-
Adapter provides the same centerline dimensions as an
H5600 series relief valve installed with a 2˝ long nipple.
½˝ EZ-Adapter, p/n 40-0331. ¾˝ EZ-Adapter, p/n 40-0332.
OUTLET
INLET
OUTLET
OUTLET
INLET
OUTLET