7404-10 Operations Manual
Rev A 7/25/2014
Page 18 of 82
SECTION 4 – ACCESSORY INSTALLATION
Connecting Alarm Contacts (ALRM302)
With the purchase of ALRM302, a set of terminals on the rear of the unit is provided to
monitor temperature and humidity alarms.
With the alarm contacts, the terminals provided allow for a NO (normally open) output, a
NC (normally closed) and COM (common) connection. In the event of an alarm
condition or power failure, the NO contact will close, and the NC contact will open. Once
the alarm is cleared, the contacts return to their normal conditions. Insert the
appropriate wire into the terminal and tighten down the screw terminal on top of the
connector.
Terminal Connection
Unit off
Normal
Alarm
N/O to C
Closed
Open
Closed
N/C to C
Open
Close
Open