Type MR108
7
Upstream Control Line Installation
!
WARNINg
Personal injury, equipment damage or
leakage due to escaping fluid may result
if the bonnet (key 61, Low-Pressure
Actuator) or lower diaphragm casing
(key 62, High-Pressure Actuator) is
backed off or loosened when installing
control line.
The Type MR108 backpressure regulator requires
an upstream control line to allow inlet pressure to
register on the actuator’s diaphragm to ensure proper
pressure control. A 1/2 NPT control line connection
is located on the bonnet (for low-pressure actuator,
see Figure 2) or on the lower diaphragm casing (for
high-pressure actuator, see Figure 2). The control line
should be installed four to eight pipe diameter before
the backpressure regulator and in an area of pipe that
is free of turbulence.
Connect the upstream control line tubing to the bonnet
or lower casing and run the tubing approximately
20 in. / 0.5 m upstream. For best results, the outer
diameter of the control line tubing should be 3/8 in. /
9.5 mm or larger.
Vent Line Installation
The Type MR108 backpressure regulator has a
1/2 NPT vent opening in the spring case. When
installed inside a building or if it is necessary to vent
escaping gas away from the regulator, install a remote
vent line in the spring case tapping. Vent piping should
be as short and direct as possible with a minimum
number of bends and elbows. The remote vent line
should be at least 1/2 in. / 13 mm outer diameter
tubing or 1/2 NPT pipe.
Remove the Type Y602-12 vent and the pipe bushing
(key 76, Figure 4) and attach the vent line at this
location. The other end of the vent line should be
located outside with a screened vent (Type Y602-12
vent connector). The Type Y602-12 vent connector
should be pointed down and protected as described in
the Installation Location section.
Installation Location
CAUTION
This regulator can be installed in a pit,
which is prone to flooding. The vents of
the spring case and lower diaphragm
casing (High-Pressure Actuator) or
bonnet (Low-Pressure Actuator) should
be above the expected flood level or vent
lines should be installed to terminate
above the water level so that they are
exposed to atmospheric pressure.
• The installed regulator should be adequately
protected from vehicular traffic and damage from
other external sources.
• Install the regulator with the vent pointed
vertically down, see Figures 2 and 3. If the vent
cannot be installed in a vertically down position,
the regulator must be installed under a separate
protective cover. Installing the regulator with the vent
down allows condensate to drain, minimizes the entry
of water or other debris from entering the vent and
minimizes vent blockage from freezing precipitation.
•
Do not install the Type MR108 in a location where
there can be excessive water accumulation or ice
formation, such as directly beneath a downspout,
gutter or roof line of building. Even a protective
hood may not provide adequate protection in
these instances.
• Install the regulator so that any gas discharge through
the vent or vent assembly is over 3 ft. / 0.9 m away
from any building opening. Periodically check all vent
openings to be sure that they are not plugged.
Regulators Subjected to Heavy
Snow Conditions
CAUTION
To protect against precipitation, make
certain that the vents are oriented
such that the opening does not allow
precipitation to enter vents.
Some installations, such as in areas with heavy
snowfall, may require a hood or enclosure to protect
the regulator from snow load and vent freeze over.
