Swagelok LPRS4 Series, User Manual, Page: 21 / 24

21
Troubleshooting
Symptom Cause Remedy
The outlet pressure creeps up,
without adjusting the spring. A damaged poppet and/or
seat.
Replace the poppet and/or seat.
Leakage around the body plug. A damaged O-ring. Replace the O-ring.
Leakage between the body and
the spring housing or through the
spring housing weep hole.
A damaged diaphragm or O-
ring.
Replace the diaphragm or O-ring.
Insufficient torque on the cap
screws.
Tighten the cap screws per Table 2.
Controlled pressure drops off
sharply even when the flow is
within regulator capabilities.
The system filter element is
clogged.
Replace the system filter.
The required outlet pressure
cannot be reached. The inlet pressure to the
regulator is not high enough.
Ensure that the inlet pressure to the
regulator is equal to or greater than the
desired set pressure.
The outlet pressure rises too
much when going from a dynamic
to a static situation.
There is too much flow in the
dynamic situation.
A larger regulator or parallel regulator is
required.
Review application flow capacity and
contact your local authorized sales and
service center.
The outlet pressure does not drop
when the knob is adjusted
counterclockwise.
The regulator is non-venting.
A shutoff valve in the outlet line must be
opened to reduce the outlet pressure.
The outlet pressure has changed
without adjusting the handle.
Changes to the inlet pressure
may result in changes to the
outlet pressure. Maintain a constant inlet pressure to the
regulator. See “
Points of Attention
Before Operation
” about
dependency .
Changes to the flow may result
in changes to the outlet
pressure. Maintain a constant flow through the
regulator. See “
Points of Attention
Before Operation
” about
droop .
Table 3