Sentry Sample II Low Pressure Installation, Operation & Maintenance Manual page 28

VREL/Needle Valve
Applying excessive torque on the PRV Shaft or PRV coupling will result in damage to the unit .
Follow the appropriate procedure when dislodging PRV .
In the event of a blockage, it can normally be cleared by fully opening the valve. Care must
be taken to ensure that temperature and pressure limits are not exceeded during this
process. Do not apply excessive torque to PRV shaft or PRV coupling. If the PRV cannot
be fully open by hand or by using the motor, then it may be necessary to remove the PRV
and manually clean the debris from the PRV. To manually clean the VREL valve follow the
procedure below:
1. Close the sample inlet isolation valve on the Sample Sentry II.
2. Remove power from the Sample Sentry II.
3. Remove and clean debris from VREL valve.
4. Verify VREL valve shaft opens and closes freely with little resistance.
5. Replace VREL valve (replacing VREL valve near the fully open position reduces startup
time).
a. When the coupling is installed it is necessary to ensure proper spacing. See
procedure in maintenance section.
6. Apply power to the Sample Sentry II.
7. Wait for Sample Sentry II unit to finish its startup routine (date screen will no longer be
shown).
8. Open sample inlet isolation valve on the Sample Sentry II.
If the VREL seal develops a leak, the seal requires replacement. A VREL seal kit is available.
Refer to the "Spare Parts List" on page 37 of this manual for further information.
Inlet Isolation Valve
Occasionally during initial start up or restart of the sample panel, the inlet isolation valve
packing will leak. If this occurs, remove the handle, tighten the packing nut and replace
the handle. If the packing continues to leak, the packing may need to be replaced. Refer to
the "Spare Parts List" on page 37 of this manual for further information.
Backpressure Regulating/Relief Valve
The only serviceable part of the BPR/RV is the diaphragm. Detailed instructions are
included with the replacement diaphragm. Refer to the "Spare Parts List" on page 37 of
this manual for ordering information. No pressure adjustment is available.
28 Sentry Equipment Corp