Siemens 125-5033 - Manual (Page 24)

Fume Hood Controller Owner's Manual
16 Siemens Building Technologies, Inc.
In addition to setting up the purge sequence to effectively handle the exhaust needs,
decisions must be made on how to use the information available at the central reporting
station. Consult your local Siemens Building Technologies, Inc. representative for more
information on central reporting and trending of emergency purge information.
Fail-safe Operation
If the Fume Hood Controller or one of its accessories fails, then a failure mode sequence will
be initiated.
Fume Hood Controller
If the Fume Hood Controller power fails, the exhaust flow control device will go to the full
open position. Since there would be no power to the controller, no LEDs or display will be
available on the ODP.
NOTE: If the power fails to both the exhaust fan and the controller, there will be no
indication except for the absence of the noise that the air makes during
normal operation.
ODP
If the ODP fails, the controller will continue to control the fume hood face velocity. However,
no display or audible alarming will be available.
Differential Pressure Transmitter
If the differential pressure transmitter fails, the controller will control the exhaust flow control
device to the fully open position. The ODP will display FFF and GENERAL FAILURE.
Electronic Actuator Assembly
If the electronic actuator or interface board fails then alarms are displayed on the ODP
indicating unsafe operating conditions.
Pneumatic Actuator
If the actuator fails due to a leak, then the exhaust flow control device will go to the full open
position. Alarms will be displayed on the ODP indicating unsafe operating conditions.
AO-P Module
If the AO-P module fails, alarms will be displayed on the ODP indicating unsafe operating
conditions.