Sentry Sample II Low Pressure Installation, Operation & Maintenance Manual page 14

Clean: When the self-clean feature is enabled, the controller periodically actuates the
Sentry VREL® valve in an attempt to free potential blockages. The cleaning cycle closes
the sample valve SV-2, opens the VREL valve 5 turns, closes the VREL valve 10 turns, opens
the VREL valve 10 turns, then closes the VREL valve 10 turns, SV-2 opens and the system
returns to automatic operation. This process takes approximately 50 seconds during which
your analysis will be off line. Either the MODBUS or alarm relays can be used to monitor
when the system is in a cleaning cycle.
Alarm Screen
Figure 6. Alarm Screen
Figure 6 shows a typical alarm screen. Anytime an alarm condition occurs, the alarm
screen takes priority over the existing screen. The alarm screen flashs twice per second,
alerting the operator of the problem. After the alarm condition has cleared, pressing the
MENU button resets the alarm.
Resetting Alarms
High Temperature Alarm
A high temperature alarm occurs when the outlet temperature is greater then the high
temperature alarm setpoint. When this alarm occurs, valves SV1, SV2 and the VREL valve
close. The alarm condition cannot be reset until the outlet temperature falls below the
high temperature alarm setpoint. Pressing the Menu (Reset) button resets the alarm and
allows normal operation.
On newer models (11/16/11 and later) a couple of options have been added.
1. When in a high temperature alarm, the user can cool the Sample Sentry II down by
opening SV1 and opening the PRV. Press and hold the ESC button to open SV1. Release
the ESC button to close SV1.
2. To open the PRV while in high temperature alarm, hold the ESC button down and
press the Up and Down arrows to adjust the PRV. This allows flow to cool the Sample
Sentry II.
3. In the event that the high temperature setpoint was inadvertently set below your
desired high temperature setpoint and you are unable to clear the alarm, holding
the ESC button and pressing Enter adjusts the high temperature alarm setpoint to 5
degrees above the current outlet temperature. This allows you to reset the alarm and
use the menu screens to set the correct high temperature alarm setpoint.
Options 1 and 2 above should only be used once you have corrected the event that casued the
high temperature condition on the sample outlet . Failure to ensure proper cooling can result in
a situation where steam is being sent through the Sample Sentry II .
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A l a r m
H i g h T e m p e r a t u r e
T o u t = 1 2 5 F
Sentry Equipment Corp