Overpressure Protection - Fisher R622 Instruction Manual

Type R622
gas. To avoid such injury and damage,
install the regulator in a safe location.
a regulator may vent some gas to the
atmosphere in hazardous or flammable
gas service, vented gas might accumulate
and cause personal injury, death or
property damage due to fire or explosion.
Vent a regulator in hazardous gas service
to a remote, safe location away from
air intakes or any hazardous location.
The vent line must be protected against
condensation or clogging.
Before installing the regulator, check for damage
which might have occurred in shipment. Also check
for dirt or foreign matter which may have accumulated
in the regulator body or in the pipeline. Apply pipe
compound to the external threads of the pipeline and
install the regulator so that the flow is in the direction
of the arrow cast on the side of the body. The
diaphragm actuator assembly can be rotated to any
position relative to the body, in 90° increments.
Do not install the regulator in a location where there
can be excessive water accumulation, such as directly
beneath a downspout or in an undrained pit.
To obtain the maximum flow capacities or other
performance characteristics, the length of pipe from the
regulator outlet to the meter—or for the first 18-inches
(457 mm), whichever is closer—should have no bends
and should be the same size as the regulator outlet.
Replace the regulator if water gets into the spring case
or the lower casing of the regulator.
Type R622 regulators have a spring case vent
(3/4 NPT) which is screened to prevent insects or
foreign material from entering.
You are advised to use new vent piping
because defective threads on the relief
vent piping may interfere with the venting
assembly if the piping obstructs the
movement of the vent flapper.
On indoor installations, the vent should be piped
outside the building, see Figure 3. Remove the screen
from the regulator vent connection and connect vent
piping from that connection to the outdoors. Vent
piping should be as large in diameter as practical, be
as short as possible, and have a minimum number
of bends and elbows. Install a weather and insect
resistant vent assembly on the outside end of the
pipe, such as a Type Y602. The same installation
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Figure 3. Typical Vent Line Installation
precautions apply to vent assemblies as the integral
regulator vents described previously.
A program of regular inspection of the vent opening
should be established to see that it has not become
plugged by foreign material. On some installations,
such as in areas of heavy snowfall, it may be
necessary to install the regulator beneath a protective
hood. If other protection is provided from the elements,
the vent should be pointing or sloping down sufficiently
to allow any condensate to drain. Also check the
regulator periodically for external or internal corrosion.

Overpressure Protection

WaRning
!
Some type of overpressure protection
is needed if actual inlet pressure can
exceed the outlet pressure rating.
Overpressuring any portion of this
equipment above the limits given in the
Specification section and table 1 may
cause damage to regulator parts, leaks
in the regulator, or personal injury due to
bursting of pressure-containing parts or
explosion of accumulated gas.
Type R622 regulators provide internal relief that limits
the total outlet pressure build-up over setpoint. This
internal relief may be adequate for most application,
if not, provide additional pressure relief or a pressure-
limiting device downstream. Regulators should be
inspected for damage after any overpressure condition.
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