T208VR Series
6
Warning
!
To avoid personal injury, property
damage or equipment damage caused by
sudden release of pressure or explosion
of accumulated gas, do not attempt any
maintenance or disassembly without
first isolating the regulator from system
pressure and relieving all internal
pressure from the equipment.
Vacuum regulators that have been
disassembled for repair must be
tested for proper operation before
being returned to service. Only
parts manufactured by regulator
Technologies should be used for
repairing Fisher
®
vacuum regulator.
restart gas utilization equipment
according to normal startup procedures.
general Maintenance
1. Visually inspect the vacuum regulators and its
parts for any damage.
2. Ensure tight connections, tight seals and safe
operation. If there is an evidence of leakage
or unstable internal motion, a rebuild with seal
replacement and relubrication may be necessary.
3. Observe the controlled upstream vacuum pressure
and downstream vacuum source pressure.
Body area
To gain access to the disk assembly and body gasket,
follow this procedure. Before the following steps can be
performed, release all pressure from the diaphragm case.
Key numbers are referenced in Figures 3 and 4.
1. To inspect and replace the disk holder assembly
(key 13), remove the body cap assembly (key 43).
2. If it is necessary to replace the disk holder
assembly (key 13), remove it from the disk spacer
(key 44).
3.
To inspect the orifice (key 5) on Types T208VR
and T208VRM or throat seal O-ring (key 31) and
machine screw (key 34) on the Type T208VRM,
remove the cap screws (key 2) and separate the
lower casing (key 4) from the body (key 1).
4.
Remove and inspect the body seal O-ring (key 11).
For Type T208VRM, also inspect the throat seal
O-ring (key 31) by removing the machine screw
(key 34). Replace if necessary. To install a throat
seal, place the O-ring on the machine screw and
thread into guide insert (key 18) to seal.
5.
Inspect the orifice (key 5) by carefully running your
finger along the edges to check for nicks or dents;
replace if necessary. Lightly lubricate the threads
of the replacement orifice with a good grade of light
grease and tighten using 340 to 470 inch-pounds /
38.5 to 53.1 N•m.
6. If necessary, install the replacement backup ring
(key 49) and body seal O-ring (key 11) into the
body (key 1).
7.
Replace the body (key 1) on the diaphragm casing
(key 4) and secure with the cap screws (key 2) using
90 to 126 inch-pounds / 10.2 to 14.2 N•m of torque.
note
The disk holder assembly (key 13) is
comprised of the disk and disk holder.
8.
Install the disk holder assembly (key 13) and
secure it to the disk spacer (key 44).
9.
Place the back disk spring (key 41) and a new
back body seal O-ring (key 11) on the back body
cap (key 43).
10. Lightly lubricate the threads when replacing the
body cap assembly. Use 340 to 470 inch-pounds /
38.5 to 53.1 N•m of torque.
Diaphragm and Spring Case area
To gain access to the control spring, diaphragm
assembly, valve stem and stem O-ring, follow this
procedure. All pressure must be released from the
diaphragm case before performing the following steps.
