Part No. 4801-5307 Rev 2-15 Evolution 3000 and 3001 43 of 70
8. Fail-Safe Relay Operation
There are two types of Relay strips used in the Evolution. The Normally Open (NO) strip requires a signal
from the controller board in order to energize a stage of ventilation. Should power be removed from the
EV-3000 or 3001, the Normally Open Relay strips would not be able to energize a ventilator. On the other
hand, the Fail-Safe relay strip would close each of the relays in the strip resulting in energizing the
ventilators in case of a controller power failure. Each of the relay strips contains four relays for controlling
four stages. In the EV-3000 or 3001 there are a total of four relay strips; Three will be N.O. and one will
be a Fail-Safe. The operator must insure that the Fail-Safe relay strip is connected only to stages that should
be turned on in case of a controller failure. See the Section 9.9 for a physical description of the relay strips.
It is not recommended to place heating equipment on Fail-Safe stages.
WARNING: The Fail-Safe Relay Card Is Not Recommended For Use On Timer Stages.
Fail-Safe Relay Card Normally Open Relay Card
NOTE:
Older versions of the
Fail-Safe Relay Cards
will not have the
Yellow Warning
Label.
Look for the “FAIL-
SAFE RELAY
STRIP” text visible
on this end of the
Fail-Safe Relay Card
circuit board.
NOTE:
The Normally Open
Relay Card will have
the “N.O. RELAY
STRIP” text visible
on this end of the
Relay Card circuit
board.
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