Technical Specifications

15
Troubleshooting
First Steps
1. Verify the regulator specifications fit the application
conditions.
Min/max inlet pressure, control pressure range &
min/max operating differentials should be checked
to make sure the regulator and pilot are designed to
operate in the present conditions.
2. Verify the regulator is piped correctly.
Even though the regulator may have operated in the
past, check that current piping connections match
recommendations on pages 7-10.
3. Verify the regulator is sized correctly.
Regulators operating below 10% or above 80% of
their maximum capacity given current application
conditions tend to have more problems. Consider
reduced capacity trim or a larger regulator in these
cases.
Potential Issues
Regulator does not shut off.
1. Refer to the failure mode chart to diagnose
potential causes.
2. Clean or replace regulator and pilot components as
necessary.
Erratic Control.
1. Check for damage, debris in the restrictor and
control pilot. Replace, clean and lubricate compo-
nents as necessary. Consider pilot supply filtration
(Type 30 Filter).
2. Check for the potential of hydrate formation or
freezing liquids in the pilot system. If liquids are pres-
ent consider gas conditioning before the pilot and/or
regulator, heating the supply gas to the regulator, or
heating the pilot supply gas (pilot gas heater).
3. Check the sense line location and assure it is away
from turbulent locations. Moving the sense line to a
new location often solves control problems.
4. Check to make sure needle regulators are not used
on any pilot system connections. Full opening type
such as ball regulators are recommended.
5. Check for pilot vent port blockage.
Instability & Speed of response issues.
1. Change restrictor setting. Refer to page 11.
2. Check the sense line location and assure it is away
from turbulent locations. Moving the sense line to a
new location often solves control problems. Factory
recommendation is 8-10 pipe diameters away from
sources of turbulence such as tee’s, elbows, reducers,
regulators, etc.
3. Check to make sure needle regulators are not used
on any pilot system connections. Full opening type
regulators are recommended.
4. Check for pilot vent port blockage.
The regulator will not regulate to set point or
“droops-off”.
1. Check for proper sizing. The regulator may be running
out of capacity during peak demand periods.
2. Adjust the restrictor to a higher gain (smaller) setting.
Refer to page 11.
The regulator fails open or fails closed.
1. Refer to the table below to diagnose failure modes.
Problem
Failure Mode
Fail
Open
Fail
Closed
Damage to the flexible element X X
Damage to the flexible element on the
upstream side (less likely)
X
Damage to the flexible element on the
downstream side (more likely)
X
Debris between the flexible element and
the seat
X
Blockage of pilot supply pressure X
Blockage
1
of the restrictor X
Blockage
1
of the pilot supply line X
Loss of the sense line (PRV pilot) X
Loss of the sense line (Relief Pilot) X
Blockage
1
of pilot discharge X
Pilot diaphragm rupture if (PRV pilot) X
Pilot diaphragm rupture if (BPV relief pilot) X
Blockage
1
of pilot orifice X
1
Blockage can be caused by debris, hydrates, freezing or damage to the
component involved.
Table 7