Overpressure Protection - Fisher 627F Instruction Manual

To remotely vent the pilot, remove the vent and install
obstruction-free tubing or piping into the 1/4 NPT
vent tapping. Provide protection on a remote vent by
installing a screened vent cap into the remote end of
the vent pipe.
If the regulator requires repositioning, refer to the
Body Area Maintenance procedures and/or the
Diaphragm Case Area Maintenance procedures in
the Maintenance section to reposition the regulator
for the application.
The Type 627F regulator requires a downstream control
line. Install the control line before putting the regulator
into operation. Ensure that the downstream control
line piping is at least 3/8 inch / 9.5 mm or larger outside
diameter tubing and connected to a straight section of
outlet piping several pipe diameters downstream of the
regulator. Connect the other end of the control line to
the pilot side connection (marked "sense").
The Type 627F regulator also requires inlet pressure to
be piped to the pilot supply connection (see Figure 2).
If the optional factory pilot supply piping was not
selected, run a 3/8 inch / 9.5 mm outer diameter or
larger supply line from the upstream pipeline or from
the 1/4 NPT body tap (ductile iron body only) to the
pilot inlet connection marked "in".
Do not make the upstream pipeline connection in a
turbulent area, such as near a nipple, swage, or elbow.
To properly isolate the regulator, install a hand valve in
the pilot supply line, and provide vent valves to relieve
pressure from the regulator.

Overpressure Protection

!
Personal injury, property damage,
equipment damage, or leakage
due to escaping gas or bursting of
pressure-containing parts may result
if this regulator is overpressured or
is installed where service conditions
could exceed the limits given in
Specifications section or where
conditions exceed any ratings of the
adjacent piping or piping connections.
To avoid such injury or damage, provide
pressure-relieving or pressure-limiting
devices (as required by the appropriate
code, regulation, or standard) to
prevent service conditions from
exceeding limits.
WARNING
Additionally, physical damage to the
regulator could cause personal injury or
property damage due to escaping gas.
To avoid such injury or damage, install
the regulator in a safe location.
Startup and Adjustment
Startup
!
To avoid personal injury or property
damage due to explosion or damage to
regulator or downstream components
during startup, release downstream
pressure to prevent an overpressure
condition on the diaphragm of
the regulator.
In order to avoid an overpressure
condition and possible equipment
damage, pressure gauges should
always be used to monitor pressures
during startup.
1. Slowly open the upstream shutoff valves to the
pilot and the regulator inlet.
2. Slowly open the downstream shutoff valves to the
pilot sense connection and the regulator outlet.
3. Check all connections for leaks.
4. Make final pilot control spring adjustments
according to the Adjustment procedures. Standard
factory setpoint is approximately mid-range of the
pilot spring range.
Adjustment
The range of allowable pressure settings is marked
on the pilot. If a pressure setting beyond this range
is necessary, substitute the appropriate pilot control
spring. Change the pilot stamping to indicate the new
pressure range.
The only adjustment necessary on a Type 627F
regulator is the pressure setting of the pilot control
spring. Turning the pilot adjusting screw clockwise
into the spring case increases the spring compression
and pressure setting. Turning the pilot adjusting screw
counterclockwise decreases the spring compression
and pressure setting.
Type 627F
WARNING
5