Instruction Manual

Types 1808 and 1808A
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
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1. When installing the relief valve or backpressure
regulator, make sure that the system installation
complies with applicable local, state, and federal
codes and regulations.
2. Use qualied personnel when installing, operating,
and maintaining the relief valve or backpressure
regulator. Before installing the unit, inspect the
main valve body, pilot, and pipelines for any
damage or foreign material that may have
collected. Apply pipe compound to the external
pipeline threads only. Do not use pipe compound
on any internal threads.
3. The relief valve or backpressure regulator may
be installed in any position as long as pipeline ow
complies with the ow arrow on the main valve
body (Type 1808) or runs in through the bottom
connection and out the side connection
(Type 1808A). Superior performance may be
obtained by disconnecting the pilot supply tubing
from the elbow (key 36, Figures 3 and 4),
removing the elbow, installing 1/4 NPT pipe plug
into the lower casing (key 2), and connecting the
pilot supply tubing to an upstream location.
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4. The pilot exhaust may be piped directly into the
main valve outlet (if the exhaust is to be retained,
as in liquid service) or vented to the atmosphere.
In either case, the diameter of the exhaust line or
stack should be as large as practical with a
minimum number of bends or other restrictions.
When installing this unit in relief service, be sure
to consider the jet thrust effect that will occur when
it relieves.

Relief ranges are from 3 to 125 psig (0,21 to 8,6 bar).
The individual spring range of your relief valve is
stamped on the nameplate.
Maximum inlet pressures depend upon body material
and temperature. See the Specications section
for the maximum inlet pressure of the valve. The
valve should be inspected for damage after any
overpressure condition.

1. With installation completed, slowly open the
upstream shut-off valve while using a gauge to
monitor inlet pressure. On backpressure
applications using an isolating bypass, open the
downstream shut-off valve, and close the
bypass valve.
2. If set pressure adjustment is necessary, adjust a
Type 6358 or 6358B pilot by following the
procedures in the adjustment section.